Caterpillar DP70NH DP80NH DP100NH Chassis & Mast Lift Trucks Service Manual - PDF DOWNLOAD

FOREWORD Cat Lift Trucks' 7-ton, 8-ton, and 10-ton series lift trucks, which feature low operating noise and reduced vibration and come equipped with new high-performance engine.

They are provided with a full-power shift type transmission so that the gearshifting from 1st to 2nd speed or vice versa is automatically performed by the transmission controller.

In addition, the brake system is a full-hydraulic type which produces the strong braking force by pressing the pedal lightly.

The flow divider of the hydraulic circuit is incorporated in the main control valve to simplify the hydraulic line. In addition, the instrument panel accommodates optional OK monitors which allow the operator to check the water level, air cleaner plugging, and battery condition of charge with just a glance, to improve serviceability substantially.

This Service Manual describes all of major components and their service procedures for the lift trucks listed above. We encourage you to make practical use of it while servicing the trucks.

The specifications and equipment covered in this manual will subject to change without notice according to modification of the product.

September 2017

SPECIFICATIONS Truck model

7 ton

8 ton

10 ton

kg [lbs]

7000 [15435]

8000 [17640]

10000 [22050]

Basic load center

mm [in.]

600 [23.6]

←

←

Lift height

mm [in.]

3000 [118.1]

←

←

6 - 12

←

←

215 [8.5]

205 [8.1]

←

(unloaded)

550 [108.2]

470 [92.5]

410 [80.7]

(loaded)

460 [90.6]

450 [88.6]

390 [76.8]

Item Performance Max. load

Tilt angle

(fwd-bwd) ˚ mm [in.] A

Free lift Lift speed

mm/s [fpm]

Travelling speed

km/h [mph]

fwd

1st

10 [6.2]

←

←

2nd

30 [18.6]

←

←

rev

1st

10 [6.2]

←

←

2nd

30 [18.6]

←

←

21.6 (2200 [4851])

27.4 (2800 [6174])

31.4 (3200 [7056])

52.9 (5400 [11907])

57.3 (5850 [12899])

←

(unloaded)

1/5.8

1/5.2

1/5.0

(loaded)

1/3.5

1/3.7

1/4.5

Max. drawbar pull (unloaded)

kN (kgf [lbs])

(loaded) Gradeability

Min. turning radius

mm [in.] B

3360 [132.3]

3650 [143.7]

3900 [153.5]

Min. intersecting aisle

mm [in.]

3020 [118.9]

3290 [129.5]

3540 [139.4]

Dimensions

mm [in.]

Overall length

C

4835 [190.4]

5180 [203.9]

5470 [215.4]

Overall width

D

1995 [78.5]

2165 [85.2]

2245 [88.4]

Overall height (at overhead guard)

E

2450 [96.5]

2560 [100.8]

←

Overall height (at mast)

F

2500 [98.4]

2700 [106.3]

2850 [112.2]

Overall height with extended mast

G

4420 [174.0]

←

4330 [170.5]

Wheel base

H

2250 [88.6]

2500 [98.4]

2800 [110.2]

Tread

J

(front)

1470 [57.9]

1600 [63.0]

←

(rear)

1700 [66.9]

←

←

Fork overhang

K

625 [24.6]

720 [28.4]

710 [28.0]

Rear overhang

L

740 [29.1]

←

←

1220 x 150 x 70 [48.0 x 5.9 x 2.8]

1220 x 170 x 75 [48.0 x 6.7 x 3.0]

1220 x 175 x 75 [48.0 x 6.9 x 3.0]

Fork size (Length(M) x Width(N) x Thick(P))

Q 300 - 1835 [11.8 - 72.2] 340 - 2000 [13.4 - 78.8] 405 - 2145 [15.9 - 84.4]

Fork spacing Under clearance

190 [7.5] (at front axle)

245 [9.6] (at mast)

←

9360 [20640]

10980 [24210]

12300 [27122]

Weight Operating weight

kg [lbs]

A: Free lift

Unit: mm (in)

Fig. 1 External View

TABLE OF CONTENTS 1. ENGINE ................................................................................................................................... 1 1.1 GENERAL DESCRIPTION ..................................................................................................... 1 1.1.1 FUEL SYSTEM .................................................................................................................. 5 1.1.2 COOLING SYSTEM .......................................................................................................... 9 1.1.3 ACCELERATOR PEDAL .................................................................................................. 10 1.2 INSPECTION AND ADJUSTMENT ....................................................................................... 11 1.2.1 AIR CLEANER .................................................................................................................. 11 1.2.2 FUEL FILTER .................................................................................................................... 12 1.2.3 OIL FILTER ........................................................................................................................ 12 1.2.4 COOLING SYSTEM........................................................................................................... 13 1.2.5 TIGHTENING CYLINDER HEAD BOLTS ...................................................................... 15 1.2.6 ADJUSTING VALVE CLEARANCE ................................................................................ 15 1.2.7 CHECKING INJECTION TIMING ................................................................................... 16 1.2.8 ADJUSTING INJECTION TIMING................................................................................... 17 1.2.9 MEASURING COMPRESSION PRESSURE ................................................................... 17 1.2.10 AIR BLEEDING ................................................................................................................ 17

2. DRIVE UNIT .......................................................................................................................... 19 2.1 GENERAL DESCRIPTION ..................................................................................................... 19 2.1.1 TORQUE CONVERTER .................................................................................................... 21 2.1.2 CHARGING PUMP............................................................................................................. 22 2.1.3 TRANSMISSION ............................................................................................................... 23 2.1.4 ATM CONTROLLER ......................................................................................................... 28 2.1.5 TROUBLESHOOTING GUIDE ........................................................................................ 30 2.1.6 TROUBLESHOOTING GUIDE (ATM CONTROLLER).................................................. 32

3. DRIVE AXLE ......................................................................................................................... 39 3.1 GENERAL DESCRIPTION ..................................................................................................... 39 3.1.1 DIFFERENTIAL ................................................................................................................ 42 3.1.2 FINAL REDUCTION GEAR ............................................................................................. 43

4. BRAKE SYSTEM................................................................................................................ 45 4.1 GENERAL DESCRIPTION...................................................................................................... 46

4.1.1 BRAKE PEDAL ................................................................................................................. 48 4.1.2 BRAKE VALVE ................................................................................................................. 48 4.1.3 ACCUMULATOR............................................................................................................... 50 4.1.4 WHEEL BRAKE ................................................................................................................ 51 4.1.5 PARKING BRAKE ............................................................................................................. 55 4.2 MAINTENANCE...................................................................................................................... 56 4.2.1 CHECKING WHEEL BRAKE............................................................................................ 56 4.2.2 REASSEMBLING WHEEL BRAKE (7 ton trucks)........................................................... 58 4.2.3 TESTING AUTOMATIC ADJUSTER FOR OPERATION (7 ton trucks)......................... 60 4.2.4 ADJUSTING BRAKE PEDAL........................................................................................... 61 4.2.5 ADJUSTING INCHING AND BRAKES PEDALS........................................................... 62 4.2.6 ADJUSTING CLEARANCE BETWEEN LINING AND DRUM (8 ton, 10 ton trucks)... 62 4.2.7 TROUBLESHOOTING....................................................................................................... 63

5. STEERING SYSTEM......................................................................................................... 65 5.1 GENERAL DESCRIPTION...................................................................................................... 65 5.1.1 STEERING WHEEL UNIT................................................................................................. 66 5.1.2 STEERING GEAR BOX..................................................................................................... 66 5.1.3 POWER CYLINDER ......................................................................................................... 69 5.1.4 STEERING LINKAGE....................................................................................................... 70 5.1.5 STEERING AXLE............................................................................................................... 71 5.2 MAINTENANCE ..................................................................................................................... 73 5.2.1 DISASSEMBLING STEERING GEAR BOX ................................................................... 73 5.2.2 INSPECTION...................................................................................................................... 75 5.2.3 REASSEMBLING STEERING GEAR BOX..................................................................... 76 5.2.4 ADJUSTING PRE-LOAD OF WHEEL BEARING........................................................... 80 5.2.5 TROUBLESHOOTING GUIDE ........................................................................................ 81

6. HYDRAULIC SYSTEM..................................................................................................... 83 6.1 GENERAL DESCRIPTION ..................................................................................................... 83 6.1.1 FRONT PUMP .................................................................................................................... 84 6.1.2 REAR PUMP....................................................................................................................... 85 6.1.3 CONTROL VALVE ............................................................................................................ 86 6.1.4 VALVE CONTROLS........................................................................................................... 93 6.1.5 LIFT CYLINDER................................................................................................................ 94

6.1.6 FLOW REGULATOR VALVE ........................................................................................... 98 6.1.7 TILT CYLINDER................................................................................................................ 99 6.1.8 OIL TANK........................................................................................................................... 100 6.1.9 DISASSEMBLING AND REASSEMBLING CONTROL VALVE................................... 102

7. LOAD HANDLING SYSTEM ........................................................................................ 105 7.1 GENERAL DESCRIPTION ..................................................................................................... 106 7.1.1 OUTER & INNER CHANNEL........................................................................................... 106 7.1.2 CARRIAGE ........................................................................................................................ 109 7.1.3 LOCATIONS OF ROLLERS ............................................................................................. 112 7.2 MAINTENANCE ..................................................................................................................... 114 7.2.1 ADJUSTING LIFT CYLINDER ROD WITH SHIM ........................................................ 114 7.2.2 ADJUSTING HEIGHT OF CARRIAGE ............................................................................ 114 7.2.3 PROCEDURE FOR REPLACING ROLLERS AT CARRIAGE SIDE ............................. 116 7.2.4 PROCEDURE FOR REPLACING ROLLERS AT MAST SIDE........................................ 118

8. STEERING SYSTEM (ORBITROL TYPE).............................................................. 121 8.1 GENERAL DESCRIPTION ..................................................................................................... 121 8.1.1 STEERING AXLE............................................................................................................... 122 8.1.2 STEERING WHEEL ASSEMBLY...................................................................................... 124 8.1.3 ORBITROL.......................................................................................................................... 125 8.1.4 POWER CYLINDER.......................................................................................................... 128 8.2 PREVENTIVE MAINTENANCE............................................................................................. 129 8.2.1 DISASSEMBLY AND MAINTENANCE OF ORBITROL................................................ 129 8.2.2 REASSEMBLY OF ORBITROL ........................................................................................ 132 8.2.3 ADJUSTING PRELOAD OF REAR WHEEL BEARING ................................................ 136 8.2.4 TROUBLESHOOTING GUIDE......................................................................................... 137

9. ELECTRIC WIRING .......................................................................................................... 139 9.1 ELECTRICAL SYSTEM ......................................................................................................... 139 9.1.1 INTERLOCK SYSTEM...................................................................................................... 140 9.1.2 INSPECTING SEAT BELT INTERLOCK......................................................................... 142 9.1.3 INSPECTING FUSES BOX................................................................................................ 144 9.2 WIRE HARNESS...................................................................................................................... 145

1. ENGINE

1. ENGINE Truck model

Item

7 ton

8 ton, 10 ton

Model A-6BG1QC-02 A-6BG1QC-09 Type 4-cycle, water-cooled overhead valve, direct injection diesel engine No. of cylinders - Bore x Stroke mm (in) 6 – 105 x 125 (6 – 4.13 x 4.92) 6494 (396.29) cm3 (inch3) Total displacement Compression ratio 17 Performance (rpm) 2000 2100 Rated speed Rated output kW{PS} 82.4 ± 2.9 {112 ± 4} 84.6 ± 2.9 {115 ± 4} Max. torque N-m{kgf-m (ft-lbs)/rpm} 416.5 ± 24.5 {42.5 ± 2.5 (312)}/1400 - 1600 171 ± 10 (0.4) Fuel consumption ratio gr/ps·hr (lbs/HP·hr) No-load maximum speed (rpm) 720 +40 -0 Weight kg(lbs) 450 (992) Dimensions mm (in) 1129.5 x 672.0 x 860.0 (44.5 x 26.5 x 33.9) 1-5-3-6-2-4 Ignition order Rotational direction Clockwise when viewed from fan side

1.1 GENERAL DESCRIPTION

This series of lift trucks comes equipped with the diesel engine type. The engine is connected to the drive unit. The engine proper is supported through cushioning materials to the frame to reduce vibration from the engine to the frame.

View looking from A

View looking from B

A PROPELLER SHAFT

B

TRANSMISSION DRIVE AXLE

Fig. 1.1 Engine Mounting -1-

1. ENGINE

GENERATOR

FUEL FILTER

INJECTION PUMP OIL PRESSURE SWITCH

STARTER MOTOR

Shaft torque

Max. torque 416.5±24.5 N·m {42.5±2.5 kg-m}/ 1400 - 1600 rpm

OIL FILTER

Rated output 115±4 Ps/2100 rpm

Rate of fuel consumption 171 ± 10 g/Ps·h No-load max. speed less than 2370 rpm less than 2270 rpm

Engine speed (rpm)

Fig. 1.2 Diesel Engine (6BG1)

-2-

Rate of fuel consumption

Shaft output (Ps)

112±4 Ps/2000 rpm

1. ENGINE

Main Construction Valve system

Overhead valve type

Fuel system Injection pump

In-line type

Plunger dia. x stroke

9.5 mm (0.37 in) x 8 mm (0.32 in)

Injection nozzle

Porous type

Fuel feed pump

Plunger type

Filtration

Paper filter cartridge type

Governor Governing

Centrifugal all-speed control

Lubrication

Forced circulation

Lubrication system Pump

Gear type

Drive

Cam shaft drive

Oil pressure regulator

Piston and spring

Oil pressure indicator

Switch type [turns on at 0.029 MPa {0.3 kgf/cm2 (4.3 psi)}]

Filtration

Full-flow, paper filter type

Cooling

Water cooling type (built in lubrication system)

Cooling system Cooling Cooling fan

Water cooling Pusher type with seven blades, O.D. of 550 mm (21.7 in)

Drive

Belt drive

Pump

Swirling type

Drive

Belt drive

Thermostat Type

Wax pellet type

Temperature at which it begins to open

82˚C (179.6˚F)

Temperature at which a stoke of 10 mm (0.34 in) is reached Starter motor

95˚C (203˚F)

Type

Engage magnet type

Voltage

24 V

Output

4.5 kW

Stopping device

Fuel cut-off type (motor type)

Engine preheater

Provided (Glow)

-3-

1. ENGINE

Charging generator Type

A.C. generator, diode rectification

Voltage

24 V

Output

25 A

Drive

Belt drive

Voltage/current regulator

IC type (built in charging generator)

Reference data Oil sump capacity

13 L max. - 10 L min. (3.4 U.S. gal max. - 2.6 U.S. gal min.)

Quantity of cooling water

12 L (3.2 U.S. gal [engine only]

Valve clearance Suction valve (in cold)

0.4 mm (0.016 in)

Exhaust valve (in cold)

0.4 mm (0.016 in)

Valve operation Suction valve (open)

19° BTDC

(close)

47° ABDC

Exhaust valve (open)

57˚ BBDC

(close)

15˚ ATDC

Injection timing

14˚ BTDC 14.7 MPa {150 kgf/cm2 (2133 psi)}

Injection start pressure

3 MPa {31 kgf/cm2 (441 psi)}

Compression pressure at 200 rpm

-4-

1. ENGINE

1.1.1 FUEL SYSTEM The fuel system consists of a fuel tank integral with the frame, a fuel filter and an injection pump.

(1) Fuel tank The fuel tank is welded into one integral body with the frame and located at the left side of the frame.

The fuel tank has on its top a tank cover where a tank unit is provided to check the fuel level in the tank.

OVERFLOW to INJECTION PUMP

LEVEL SENDER

OIL FILLER CAP

Full: 140 ℓ

37 U.S. gal

Empty: 21 ℓ

5.6 U.S. gal

Fig. 1.3 Fuel Tank

-5-

1. ENGINE

The tank unit converts the fuel level in the tank into an electric current signal. Figure 1.4 shows its construction. For conversion of fuel level into electric signal, a variable resistor with nichrome wire is used, with sliding element linked to a float. As the float moves up and down the resistance varies accordingly so that the amount of electric current passing across the resistance also varies. The fuel meter is a bimetal type whose pointer swings depending upon the amount of electric current passing through the heating unit of the bimetal. When the float is at the highest position, the tank unit reads a resistance of 9.5 to 11 ohms. This allows a large amount of electric current to pass through the resistance, thus causing the bimetal to bend largely so that the fuel meter pointer indicates the F mark. As the fuel level drops, the float goes down and the resistance becomes greater to reduce the amount of electric current passing through it, thus causing the fuel meter pointer to swing toward the E mark. The tank unit is provided with a level sensor which informs the operator with an optional lamp when the fuel level drops below a certain value. The fuel meter and the optional fuel lamp are incorporated in the combination meter panel as shown in Figure 1.5.

Ａ FUEL METER

FUEL LEVEL SENDER

FUEL LAMP BATTERY FULL 3/4

1/2

1/4

EMPTY

FLOAT View Ａ

Fig. 1.4 Fuel Level Sender -6-

1. ENGINE

3

1

4

12

5

11

6

10

7

8

2

9

METER PANEL (Meters) 1. FUEL GAUGE 2. HOUR METER 3. COOLING WATER TEMPERATURE GAUGE

6. RADIATOR WATER LEVEL WARNING LIGHT (OPTION) 7. CHARGE WARNING LIGHT 8. BATTERY ELECTROLYTE LEVEL WARNING LIGHT (OPTION) 9. FUEL LEVEL WARNING LIGHT 10. PARKING BRAKE WARNING LIGHT 11. SEAT BELT WARNING LIGHT 12. TRAVELING AND LOAD HANDLING INTERLOCK SYSTEM WARNING LIGHT

(Warning lights, indicator lights) 4. ENGINE OIL PRESSURE WARNING LIGHT 5. AIR CLEANER CLOGGING WARNING LIGHT

Fig. 1.5 Combination Meter Panel -7-

1. ENGINE

(2) Fuel filter The fuel filter is installed at the engine intake manifold to remove dust and dirt from the fuel to be supplied to the engine. The filter element is a cartridge type and it can be replaced without using any tool.

A by-pass valve is built into the filter body to allow the fuel to flow into the engine even if the filter element is clogged.

BY-PASS VALVE FUEL FILTER

Fig. 1.6 Fuel Filter

-8-

1. ENGINE

1.1.2 COOLING SYSTEM The cooling system consists of a water pump, a fan, a radiator and a reserve tank. Its construction is as shown in Figure 1.7.

The water pump is attached to the engine. As the engine starts running, it is driven through the V-belt.

RESERVE TANK

CAP (Valve opening pressure: 88.3 kPa {0.9 kgf/cm2} [12.8 psi])

Fig. 1.7 Cooling System

-9-

RADIATOR

1. ENGINE

1.1.3 ACCELERATOR PEDAL The accelerator pedal controls engine output. It is installed on the floor as shown in Figure 1.8. The movement of the pedal is transmitted through the linkage and wire cable to the engine.

ACCELERATOR PEDAL 48 mm (1.9 in)

CABLE

Engine side

Fig. 1.8 Accelerator Pedal

- 10 -

1. ENGINE

1.2 INSPECTION AND ADJUSTMENT

It is necessary to inspect and adjust, if necessary, the engine at periodic intervals to keep it in good operating condition. The procedure for inspecting and adjusting the engine is explained on pages that follow.

1.2.1 AIR CLEANER (1) Remove the air cleaner element.

(2) Inspect the element for contamination and damage. If element is dirty, clean it by blowing lowpressure air from inside to outside. If the element is damaged or clogged, replace it with a new one.

(3) Clean the filter cover.

Free air ELEMENT

LATCH

to ENGINE

INDICATOR COVER

BODY

Fig. 1.9 Air Cleaner Be careful not to touch the muffler and exhaust manifold since they are hot when the engine is running and for a while after it is shut off; otherwise you might burn your hand.

- 11 -

1. ENGINE

1.2.2 FUEL FILTER (1) Remove a damaged or clogged filter using a suitable filter wrench.

(2) Apply fuel on the packing of a new filter, install the filter. After the packing contacts the filter body, give another 2/3 of a turn.

BY-PASS VALVE

FILTER CARTRIDGE

Fig. 1.10

1.2.3 OIL FILTER (1) Using a suitable filter wrench, remove the filter.

(2) Apply engine oil at the packing of a new filter, install the filter. Give the filter another 2/3 of a turn after it touches the base.

FILTER CARTRIDGE

Fig. 1.11

- 12 -

1. ENGINE

1.2.4 COOLING SYSTEM (1) Checking cooling liquid

Check the cooling liquid level in the reserve tank.

If the level is below the MIN mark, add cooling liquid of 30% concentration (50 % in coldweather regions) to bring level:

Up to the MAX mark when the engine is warm.

2/3 of the capacity when the engine is cold.

(2) Changing cooling liquid Shut off the engine and wait fore more than 30 minutes.

Remove the radiator cap and loosen the drain cock at the radiator side.

Loosen the drain cock at the engine side to drain off the cooling liquid.

Tighten the drain cocks at both the radiator and the engine sides.

Fig. 1.12 Reserve Tank Add cooling liquid of 30% concentration (50% in cold-weather regions) into the radiator. The rate of addition should be less than 2 L/min (0.5 U.S. gal/min).

After adding cooling liquid, start the engine and let it run at idle rpm for a couple of minutes and check the cooling liquid level. If the level is low, add cooling liquid of the same concentration used in step , as required.

Tighten the radiator cap securely. Add cooling liquid to bring level up to 2/3 of the capacity.

DRAIN COCK

Fig. 1.13 Drain Cock Location

- 13 -

1. ENGINE

(3) Adjusting fan belt tension ① Loosen the generator fitting bolts C and C . ② Move the generator away from the engine to adjust the belt tension, so that the fan belt has a deflection of 10 mm (0.4 in) at B on the span when pressed by a finger pressure of about 98N {10 kgf (22.1 lbs)}. ③ Tighten the fitting bolts B and then A .

Fig. 1.14

- 14 -

1. ENGINE

1.2.5 TIGHTENING CYLINDER HEAD BOLTS (1) Tighten the bolts to 68.7 N·m {7.0 kgf-m (50.6 ft-lbs)} of torque in the numerical order shown in Figure 1.15.

(2) Give them additional 93.2 N·m {9.5 kgf-m (68.7 ft-lbs)} of torque.

(3) After that, retighten each bolt by 90 degrees.

Apply molybdenum dioxide.

Front side

Fig. 1.15 1.2.6 ADJUSTING VALVE CLEARANCE (1) Turn the crankshaft to the right to align the "TC" marking on the pulley dumper with the pointer.

(2) Remove the check hole cover to make sure that the plate mark is aligned with the pointer. If the plate mark is aligned with the pointer, it indicates that the No.1 cylinder is at top dead center on compression stroke. Then, adjust the valve clearances with the mark " ○ " shown in the table below. If the plate mark is not aligned with the pointer, adjust the valve clearances with the mark " ◎ ".

POINTER

Fig. 1.16

POINTER Plate mark

Check hole

Fig. 1.17 Fig. 1.18 Cyl. No. Valve arrangement No.1 cyl. at TDC on compression stroke

1

2

3

4

5

6

I E I E I E I E I E I E ○ ○ ○

No.6 cyl. at TDC on compression stroke

◎ ◎

○ ○

◎ ◎

○

◎ ◎

Valve clearance: 0.4 mm (0.02 in) (for both the suction and exhaust valves when the engine is cold.)

- 15 -

1. ENGINE

1.2.7 CHECKING INJECTION TIMING (1) Make sure that the match-mark on the flange of the injection pump is aligned with that on the cover bracket.

(FLANGE MOUNT) COVER BRACKET

"MATCH-MARK"

Fig. 1.19 (2) Make sure that the No.1 cylinder is at top dead center on compression stroke and from that state, rotate the crankshaft about 30 degrees counterclockwise.

Rotate it about 30 degrees.

Fig. 1.20 (3) Remove the injection pipe from the No.1 cylinder and detach the spring and delivery valve from the delivery valve holder. Then, install the delivery valve holder alone on the injection pump.

DELIVERY VALVE HOLDER

Fig. 1.21 (4) Rotate the crankshaft clockwise slowly while supplying the fuel under pressure with the feed pump. In this step, stop the crankshaft where the oil level in the delivery valve holder top stops increasing. Check the mark the pointer indicates.

POINTER TC MARK TIMING MARK

Fig. 1.22 - 16 -

1. ENGINE

1.2.8 ADJUSTING INJECTION TIMING (1) Remove the pipes (for fuel and lubricating oil) connected to the injection pump.

(2) Loosen the injection pump fitting bolts.

(3) Check the timing in the manner described in the item 1.2.7. If you want to advance the timing, move the injection pump away from the engine, and if you want to delay it, move the injection pump toward the engine.

(4) After adjusting the timing, tighten the injection pump fitting bolts securely and check the timing again.

(5) Install the delivery valve for the No.1 cylinder, into the pump and reinstall the pipes in their original positions.

1.2.9 MEASURING COMPRESSION PRESSURE (1) Remove the glow plugs and injection pipes from the cylinders.

(2) Install a pressure gauge (capable of withstanding 5 MPa {50 kgf/cm2 (711 psi))} on the area where the No.1 cylinder glow plug was removed from.

(3) Rotate the starter using a fully charged battery and measure the compression pressure.

(4) Compression pressure measurement should be made at least twice on each cylinder and calculate the average.

Compression pressure: 3 MPa {31 kgf/cm2 (441 psi)}

Limit: 2.6 MPa {26 kgf/cm2 (370 psi)} 1.2.10 AIR BLEEDING (1) Loosen the air bleeding plug on the injection pump.

(2) Operate the feed pump slowly until no bubbles are observed in fuel coming from the air bleeding plug hole.

(3) Reinstall and tighten the air bleeding plug securely.

Fig. 1.23

FEED PUMP

Fig. 1.24

- 17 -

1. ENGINE

NOTE

- 18 -

2. DRIVE UNIT

2. DRIVE UNIT Item

Truck model

7 ton

Type Speeds

8 ton, 10 ton

30C-25 30G-25 Automatic speed control, 2 speeds

←

3-element, 1-stage, 2-phase type

←

2.3

2.5

0.49 - 0.69 MPa

←

Torque converter Type Stall torque ratio Charging oil pressure

{5 - 7 kgf/cm2 (71 - 100 psi)}

Charging pump Type

Crescent type

←

21 cm3/rev

←

Constant-mesh power-shift

←

1st: 1.621 2nd: 0.526

←

134 mm (5.28 in) x 90 mm (3.54 in) x 2.8 mm (0.11 in)

←

1.08 - 1.47 MPa {12 - 15 kgf/cm2 (171 - 213 psi)}

←

295 kg (650 lbs)

←

23.5 L (6.2 U.S. gal)

←

SAE 10W (factory setting) or equivalent, ATF DEXRON

←

Discharge Transmission Type Gear ratio Clutch disk

Size (O.D. x I.D. x THICK) Clutch pressure setting

Weight Oil capacity Oil to be used

2.1 GENERAL DESCRIPTION

The drive unit is composed of a torque converter and a power-shift transmission. The output is transmitted to the differential through the propeller shaft.

The speed range is automatically switched over with the ATM controller.

- 19 -

2. DRIVE UNIT

CHARGING PUMP PUMP DRIVE GEAR

TRANSMISSION CONTROL VALVE

IDLE GEAR SHAFT FORWARD CLUTCH TORQUE CONVERTER

OIL SEAL OUTPUT SHAFT

REVERSE CLUTCH

OUTPUT GEAR (2ND SPEED) OUTPUT GEAR (1ST SPEED)

PARKING BRAKE

OIL SEAL

STRAINER

REGULATOR VALVE

TORQUE CONVERTER INLET RELIEF VALVE

SPEED SENSOR

Fig. 2.1 Drive Unit

- 20 -

2. DRIVE UNIT

2.1.1 TORQUE CONVERTER The torque converter consists of a pump wheel, a turbine wheel and a stator wheel as shown in Figure 2.2.

As the engine is started, the pump wheel is driven and the fluid inside the pump wheel begins to be ejected along with the row of pump wheel vanes under centrifugal force, flowing into the row of turbine wheel vanes to transmit the torque to the output shaft. The direction of fluid leaving the turbine wheel is changed by the stator wheel so that it may flow into the pump wheel at a proper angle. At this time, reaction torque pushing the stator is created so that the output torque exceeds the input torque by this reaction torque.

As the rotational speed of the turbine wheel increases enough to get closer to the input rotational speed, the angle change in the fluid will become smaller and the output shaft torque will decrease, finally letting the fluid flow into the row of stator vanes in the reverse direction, causing reverse reaction torque. As a result of this, the output shaft torque will become smaller than the input shaft torque. To prevent this from happening, the stator wheel is designed to rotate freely when reaction torque acts in the reverse direction.

The output torque is kept equal to the input torque so that highly effective operation is ensured.

Since the phase of torque transmission is converted by the mechanical means, this type of torque conversion is called 2-phase type, which ensures smooth and effective operation.

The pump wheel of the torque converter is connected through the input plate to the engine flywheel, with the pump wheel boss gear engaged with the idle gear for driving the charging pump.

INPUT PLATE

TURBINE WHEEL PUMP WHEEL

STATOR WHEEL STATOR SUPPORT

ONE-WAY CLUTCH

Fig. 2.2 Torque Converter

- 21 -

2. DRIVE UNIT

2.1.2 CHARGING PUMP The charging pump consists of a drive gear, a driven gear, a case and a cover, as shown in Figure 2.3, and is housed in the torque converter housing.

The charging pump is driven by the idle gear and pump drive gear which are driven by the pump wheel of the torque converter. The charging pump picks up oil from the bottom of the transmission case and sends it to each part of the transmission.

DISCHARGE PORT

COVER CASE

DRIVE GEAR

"O"-RING SUCTION PORT

DRIVEN GEAR

Fig. 2.3 Charging Pump

- 22 -

2. DRIVE UNIT

2.1.3 TRANSMISSION The transmission is a power-shift type consisting of a forward clutch pack, a reverse clutch pack, an output shaft group, a parking brake group and a transmission control valve. (See Figure 2.1) (1) Clutch pack Each of the forward and reverse clutch packs consists of two pairs of hydraulic clutch units. Each hydraulic clutch unit is composed of a piston, a spring, friction plates and drive plates. The piston is always forced against the drum by the spring. As the oil pressure is applied, the piston locks up the friction plates and drive plates. The clutch lock-up oil is fed through the grooves in one end of the clutch shaft while the lubrication oil is fed through the oil holes in the shaft end.

Forward clutch pack FRICTION PLATE DRIVE PLATE

GEAR

HELICAL PLATE

WASHER

2ND GEAR

RETURN SPRING

"O"-RING WASHER

SEAL RING

2ND GEAR CLUTCH OIL PRESSURE 1ST GEAR CLUTCH OIL PRESSURE

NEEDLE BEARING

NEEDLE BEARING SPACER

SPACER NEEDLE BEARING

END PLATE 1ST GEAR

SNAP RING

NEEDLE BEARING

PISTON SEAL RING

WASHER

WASHER

Reverse clutch pack FRICTION PLATE DRIVE PLATE

GEAR

RETURN SPRING 2ND GEAR

HELICAL PLATE

WASHER

"O"-RING WASHER

SEAL RING

2ND GEAR CLUTCH OIL PRESSURE 1ST GEAR CLUTCH OIL PRESSURE NEEDLE BEARING

NEEDLE BEARING

SPACER

SPACER

NEEDLE BEARING 1ST GEAR

END PLATE SNAP RING

WASHER

PISTON SEAL RING

Fig. 2.4 Clutch Pack

- 23 -

NEEDLE BEARING WASHER

2. DRIVE UNIT

(2) Transmission control valve The transmission control valve consists of two selector spools, and an inching spool, an accumulator, and a modulation valve. It is installed on the top of the transmission case.

The two selector spools change over the directions of travel and traveling speed respectively, and are operated by solenoid valves. When the clutches are changed over, the modulation valve is actuated so that the accumulator slightly extends the time needed for the clutch oil pressure to reach the maximum level.

PISTON

SOLENOID VALVE (SPEED)

PIN

SPRING

SPRING

SOLENOID VALVE (DIRECTION)

PISTON (REVERSE)

PISTON (MODULATE)

SPRING

SPRING

PISTON

SPRING

SPRING

OIL SEAL SPOOL (INCHING)

SPRING PISTON (SPEED)

PISTON (FORWARD)

Fig. 2.5 Transmission Control Valve

- 24 -

2. DRIVE UNIT

(3) Transmission oil circuit As the engine is started and the charging pump is driven, oil flows into the regulator valve, which regulates the oil pressure for 1.08 - 1.47 MPa {12 to 15 kgf/cm2 (171 to 213 psi)}. The oil relieved from the regulator valve flows, passing through the converter relief valve, torque converter, oil cooler and line filter to lubricate various parts and returns back into the transmission case.

The converter relief valve regulates the oil pressure at the torque converter inlet for 0.49 - 0.69 MPa {5 to 7 kgf/cm2 (71 to 100 psi)}. The oil cooler cools the oil and the line filter removes dust from the oil.

LINE FILTER TORQUE CONVERTER INLET RELIEF VALVE 0.49 - 0.69 MPa {5 - 7 kgf/cm2 (71 to 100 psi)}

TORQUE CONVERTER

OIL COOLER R1

R2

F1

F2

SOLENOID VALVE (SPEED)

REGULATOR VALVE 1.08 - 1.47 MPa {12 to 15 kgf/cm2 (171 to 213 psi)}

SELECTOR SPOOL (SPEED) SELECTOR SPOOL (DIRECTION)

SOLENOID VALVE (DIRECTION)

ACCUMULATOR MODULATE VALVE

INCHING VALVE

CHARGING PUMP

Fig. 2.6 Neutral ① 1st speed in forward

When the change lever is shifted into the forward position, the direction control solenoid valve changes over to the forward position, so that the piston (forward) moves to the left to allow the oil to flow into the 1st speed clutch. At this point, the oil pressure at drops quickly so that the piston (modulate) moves to the right by the spring to feed oil into the accumulator. Until the accumulator is filled with oil, the clutch oil pressure increases gradually. Once the accumulator is completely filled with oil, the clutch pressure rapidly increases to the specified value, thus locking up the clutch disks completely. As the clutch disks are completely locked up, the piston (modulate) moves to the left, draining the accumulator.

- 25 -

2. DRIVE UNIT

LINE FILTER TORQUE CONVERTER INLET RELIEF VALVE 0.49 - 0.69 MPa {5 - 7 kgf/cm2 (71 to 100 psi)}

TORQUE CONVERTER

OIL COOLER R1

R2

F1

F2

SOLENOID VALVE (SPEED)

REGULATOR VALVE 1.08 - 1.47 MPa {12 to 15 kgf/cm2 (171 to 213 psi)}

SELECTOR SPOOL (SPEED) SELECTOR SPOOL (DIRECTION)

SOLENOID VALVE (DIRECTION)

ACCUMULATOR

MODULATE VALVE

A

INCHING VALVE

CHARGING PUMP

Fig. 2.7 1st Speed in Forward ② 2nd speed in forward

When the truck speed reaches a preset value, the speed control solenoid valve operates to move the piston (speed) to the right. As the result of this, the oil at the 1st speed side of the forward clutch pack is drained to flow into the 2nd speed clutch. At this point, the oil pressure at A drops quickly so that the piston (modulate) moves to the right by the spring to feed oil into the accumulator. Until the accumulator is filled with oil, the clutch oil pressure increases gradually. Once the accumulator is completely filled with oil, the clutch pressure rapidly increases to the specified value, thus locking up the clutch disks completely. As the clutch disks are completely locked up, the piston (modulate) moves to the left, draining the accumulator.

- 26 -

2. DRIVE UNIT

LINE FILTER TORQUE CONVERTER INLET RELIEF VALVE 0.49 - 0.69 MPa {5 - 7 kgf/cm2 (71 to 100 psi)}

TORQUE CONVERTER

OIL COOLER R1

R2

F1

F2

SOLENOID VALVE (SPEED)

REGULATOR VALVE 1.08 - 1.47 MPa {12 to 15 kgf/cm2 (171 to 213 psi)}

SELECTOR SPOOL (SPEED) SELECTOR SPOOL (DIRECTION)

SOLENOID VALVE (DIRECTION)

ACCUMULATOR

MODULATE VALVE

A

INCHING VALVE

CHARGING PUMP

Fig. 2.8 2nd Speed in Forward ③ 1st speed in reverse

When the change lever is shifted into the 1st reverse position, the direction control solenoid valve changes over to the reverse side so that the piston (reverse) moves to the right to allow the oil to flow to the 1st speed side of the reverse clutch pack. For the following operation, see the item "1st speed in forward."

1ST GEAR REVERSE

SOLENOID VALVE (SPEED)

SELECTOR SPOOL (SPEED) SELECTOR SPOOL (DIRECTION)

MODULATION VALVE SOLENOID VALVE (DIRECTION)

A

Fig. 2.9 1st Speed in Reverse ④ 2nd speed in reverse

When the truck speed reaches a preset value, the speed control solenoid valve operates to move the piston (speed) to the right. As the result of this, the oil at the 1st speed side of the reverse clutch pack is drained to flow into the 2nd speed clutch of the reverse clutch pack. For the following operation, see the item "2nd speed in reverse."

SOLENOID VALVE (SPEED)

2ND GEAR REVERSE

SELECTOR SPOOL (SPEED) SELECTOR SPOOL (DIRECTION)

SOLENOID VALVE (DIRECTION)

MODULATE VALVE

A

Fig. 2.10 2nd Speed in Reverse

- 27 -

2. DRIVE UNIT

2.1.4 ATM CONTROLLER The ATM controller is a device which automatically changes over the transmission speed ranges from 1st to 2nd speed or vice versa, according to the truck travelling speed. Its overview is shown in Figure 2.11.

The travelling speed is detected by the sensor installed on the transmission. When the sensor detects a speed of 6 km/h (3.7 mph), the ATM controller turns ON the speed control solenoid valve in the transmission control valve to change the gears to 2nd speed. When the travelling speed drops to 3 km/h (1.9 mph) or less, the ATM controller turns OFF the solenoid valve to change the gears to 1st.

Note: The gearshift points can be changed with the switch as follows:

2nd speed: 7 km/h (4.3 mph) or more

1st speed: 4 km/h (2.5 mph) or less

6 km/h 7 km/h SPEED RANGE POINT SWITCH

Fig. 2.11 ATM Controller - 28 -

2. DRIVE UNIT

LUBRICATION OIL PRESSURE

CLUTCH OIL PRESSURE PUMP DISCHARGE OIL PRESSURE (PT3/8)

TORQUE CONVERTER INLET OIL PRESSURE (PT3/8)

to OIL COOLER

Fig. 2.12 Oil Pressure Check Port

- 29 -

from OIL COOLER

2. DRIVE UNIT

2.1.5 TROUBLESHOOTING GUIDE (1) Low output

Engine

Transmission

Torque Converter

Cause

Inspection method

Remedy

1. Insufficient oil pressure (1) Low oil level (2) Air from the suction side (3) Clogged strainer (4) Low discharge from charging pump (5) Defective spring of inlet relief valve (6) Worn or damaged seal ring or "O"-ring

Check oil level.

Check all joints and pipes.

Disassemble and check.

Disassemble and check.

Check spring tension.

Disassemble, check and measure.

Add oil.

Retighten and replace gaskets.

Clean and replace.

Replace.

Replace.

Replace.

2. Broken wheel vanes or the interference of vanes with other parts

Extract a small amount of oil and check the oil for foreign matter.

Replace.

1. Improper oil or bubbles in oil (1) Air from suction side (2) Low oil pressure inside torque converter causes bubbles.

Check.

Check all joints and pipes.

Check inlet oil pressure.

Retighten and replace.

Replace inlet relief valve.

2. Clutch slipping (1) Low oil pressure (2) Worn seal ring (3) Worn clutch piston ring (4) Burned clutch disk or deformed plate

1. Low output of engine

Check oil pressure.

Disassemble, check and measure.

Disassemble and check.

Check if the truck starts in forward/reverse or moves in neutral.

Replace regulator valve.

Replace.

Replace.

Replace.

Check stall rpm.

Check engine operation sound.

Check the maximum speed of engine in neutral.

Adjust or repair engine.

(2) High oil temperature

Transmission

Torque Converter

Cause 1. Low oil level 2. Clogged strainer 3. Interference of wheel vanes with other parts 4. Mixed air 5. Water is mixed in oil.

6. Large piping resistance.

7. Worn or seized bearings 1. Clutch dragging 2. Worn or seized bearings.

Inspection method

Remedy

Check oil level.

Disassemble and check.

Extract a small amount of oil and check the oil for foreign matter.

Check joints and pipes at suction side.

Extract oil and check.

Check piping for cracks or bends.

Disassemble and check.

Add oil.

Clean or replace.

Replace torque converter assembly.

Retighten or replace gaskets.

Check if the truck moves in neutral.

Disassemble and check.

Replace clutch plates.

- 30 -

Change oil.

Repair or replace.

Repair or replace.

Replace.

2. DRIVE UNIT

(3) Noise Remedy

Torque Converter

Inspection method

1.

2.

3.

4.

5.

6.

Broken input plate Broken or worn bearing Broken gear Worn splines Noisy pump.

Loose bolts

Check operating sound at low rpm.

Disassemble and check.

Disassemble and check.

Disassemble and check.

Disassemble and check.

Disassemble and check.

Replace input plate.

Replace.

Replace.

Replace.

Repair or replace.

Retighten or replace.

Transmission

Cause

1.

2.

3.

4.

Worn or seized bearings Broken gears Worn spline Loose bolts

Disassemble and check.

Disassemble and check.

Disassemble and check.

Disassemble and check.

Replace.

Replace.

Replace.

Retighten or replace.

(4) No power is transmitted.

Transmission Torque Converter

Cause 1. Broken input plate 2.

3.

4.

5.

Low oil level Failure of oil pump drive system Broken shaft No oil pressure is produced.

1.

2.

3.

4.

5.

Low oil level Defective seal ring Burned clutch plate Broken shaft Worn shaft spline.

Inspection method

Remedy

Check operating sound at low rpm. or check if front cover rotates.

Check oil level Disassemble and check.

Disassemble and check.

Check for suction pressure at pump's suction side.

Replace.

Check oil level.

Disassemble and check.

Check clutch oil pressure.

Disassemble and check.

Disassemble and check.

Add oil.

Replace Replace.

Replace.

Replace.

Add oil.

Replace.

Replace.

Replace.

(5) Oil leakage Torque converter and transmission

Cause 1. Defective oil seal 2. Improper connection of case 3. Loose connections and pipes 4. Loose drain plug.

5. Oil spouts from breather.

6. Oil level is too high.

Inspection method Disassemble and check oil seal lip and the mating sliding surface for wear.

Check.

Check.

Check.

Drain oil and check for mixed water.

Check if air is not sucked through the suction joints.

Check air holes in air breather.

Check oil level.

- 31 -

Remedy Replace oil seal.

Retighten or replace gasket.

Correct or replace pipe gaskets.

Retighten or replace gasket.

Change oil.

Retighten or replace packing.

Correct.

2. DRIVE UNIT

2.1.6 TROUBLE SHOOTING GUIDE (ATM CONTROLLER) (1) Truck neither moves in forward nor reverse direction With the engine shut off, press the pushbutton SW of the direction control solenoid valve to check for operation. (Refer to Note.)

NG

Replace the solenoid valve

OK

NG

With the key switch in ACC, operate the direction control lever. Check the pushbutton SW of the direction control solenoid valve for proper operation.

NG

OK

Check the continuity of harnesses.

(See page 34.)

NG

Connect the harnesses properly.

OK

NG

Replace the relay. (See page 35.)

NG Replace the direction control lever.

NG

Replace the direction control spool.

Replace the solenoid valve.

NG

NG

Remove the coupler of the direction control solenoid valve and start the engine. Press the pushbutton SW of the solenoid valve to check to see if the truck moves. (The truck moves while the switch is being pushed.)

NG

Disassemble the control valve and check the direction control spool for sticking.

OK Check the transmission side, such as the clutch packs.

Note: Direction control solenoid valve

Push to move in forward

Push to move in reverse

Transmission control valve

- 32 -

2. DRIVE UNIT

(2) Gears won't shift into second speed Check that the speed select switch is in "Standard mode" position.

Remember that the gears can not be shifted in "Hill mode".

NG

Switch to "Standard mode".

NG

OK Check that the fuses (10A at the bottom in the fuse box, WG wire on the box side and Y wire on the loader harness side) for blown-out.

NG

Replace the fuse.

NG

OK

NG

Check the speed control solenoid valve for proper operation. (See “Check C” on page 36.)

Replace the solenoid valve.

NG

OK

NG

Check the speed sensor for proper operation.

(See “Check D” on page 36.)

Replace the sensor.

(See pages 36 and 37.)

NG

OK Rise the front wheels off the ground and remove the coupler from the speed control solenoid valve. Connect the tester rods to the BL and GL of the coupler.

Check for 24 volts between BL and WL when the speed is more than 6 km/h (3.7 mph).

NG

Replace the controller.

NG

OK Check the coupler connected to the speed control solenoid valve for poor connection.

(Make sure that the plug is straight on the solenoid valve side)

NG NG

OK Disassemble the control valve and check the speed control spool for sticking.

OK Check the transmission side, such as clutch packs.

- 33 -

Fix the plug.

Remove the orange part in the coupler on the loader harness side if it is faulty.

2. DRIVE UNIT

Check A. Checking continuity of harnesses Note: See the wire harness drawing on pages 154 to 155.

YR, change lever

YR, F/R relay (F) YR, F/R relay (R)

O, change lever

O, interlock relay

BR, interlock relay

BR, neutral relay

Check without exception.

LR, change lever

LR, safety relay

B, change lever

B, F/R relay (F) B, safety relay

Br, neutral relay

Br, safety relay

GY, safety relay

GY, diode GY, diode

G, F/R relay (F)

G, change lever

If truck doesn’t move in forLgR, solenoid valve (direction) ward, check the following:

Lg, diode

LgR, dyode

WY, F/R relay (R)

WY, change lever

If truck doesn’t move in BO, solenoid valve (direction) reverse, check the following:

V, diode

- 34 -

Lg, F/R relay (F) Lg, diode

BO, diode V, F/R relay (R) V, diode

2. DRIVE UNIT

Check B. Checking relays

①

Fuse box

②

Relay ① : Neutral relay Relay ② : Safety relay Relay ③ : F/R relay (F) Relay ④ : F/R relay (R) ③

Color of harness (BR, Br, Y, WR) (GY, B, LR, Br) (G, B, YR, Lg) (YR, WY, YR, V)

④

(Electric plate)

Fault Remedy

Engine won't start

Replace relays ① , ② , ③ , and ④ .

Truck moves in neither forward nor reverse

Replace relays ③ and ④ .

Truck does not move in forward

Replace relay ③ .

Truck does not move in reverse

Replace relay ④ .

- 35 -

2. DRIVE UNIT

Check C. Checking the speed control solenoid valve for proper operation

m 0m

SUMITOMO DENSO 2P(F) 6195-0003

(2

in)

5

LW LW

B

CA104

B 1000 mm (39 in)

* Wire AVS1.25 * Terminal arrangement inside connector is viewed from terminal side

CA104

① Remove the coupler (loader harness) from the speed control solenoid valve. Connect the harness (79875-00525) given above, with the plug connected to the loader option harnesses LW and B. ② Turn the key SW to ACC to check if the solenoid valve operates. You can check the valve for proper operation by touching it with fingers or hearing for clicking sound.

Check D. Checking the speed sensor for proper operation (Instruction after replacement of the sensor)

SPEED SENSOR CONNECTOR

TESTER

① Raise the front wheel off the ground. ② Disconnect the speed sensor connector from the wire harness (engine). ③ Set the tester in the range AC10V and insert the tester rods into the connector terminals. (It doesn't matter about polarity, because this is carried out for measuring potential difference.) ④ Start the engine and shift the direction control lever to forward or reverse. Press the accelerator pedal.

The sensor operates if the tester reads the voltage (approx. 0.1 to 1.0 V).

- 36 -

2. DRIVE UNIT

(Instruction after replacement of the sensor) Turn the sensor until the tip of the speed sensor touches the gear lightly. Then back off one full turn.

As a rule of thumb, a reference value is given below.

Note: Apply sealing agent to the threaded area of the speed sensor.

24 mm (0.94 in) reference value

- 37 -

2. DRIVE UNIT

NOTE

- 38 -

3. DRIVE AXLE

3. DRIVE AXLE Truck model

7 ton

8 ton

10 ton

Full-floating type

←

←

8.25-15-14PR(I)

9.00-20-14PR(I)

←

J-LUG

←

←

Type

Disk type

←

←

Size

6.50T-15

7.00T-20

←

0.79 MPa {8.0 kgf/cm2 (113.8 psi)}

0.74 MPa {7.5 kgf/cm2 (106.7 psi)}

←

4.75

6.33

←

Item Type Wheel Size Tread pattern Rim

Tire inflation pressure

Differential Reduction ratio

3.1 GENERAL DESCRIPTION

The drive axle has a construction as shown in Figures 3.1 and 3.2 and is mounted on the front area of the frame.

It has a wheel hub and a wheel brake at its spindle and an axle shaft running through its center. The wheel hub is provided with a brake drum, which is installed on the spindle through two tapered roller bearings. The two taper roller bearings have oil seals to prevent grease inside from oozing out and water from entering the brake unit.

- 39 -

3. DRIVE AXLE

①

②

③

④

⑤

⑥

⑦

⑧

⑨

⑩

⑪

⑫

⑬ ⑭ Tightening torque: ⑮ 96.1 - 110.8 N·m {980 - 1130 kgf-cm (70.88 - 81.73 ft-lbs.)} (Apply LOCTITE#262.)

Tightening torque: 274.6 - 323.6 N·m {2800 - 3300 kgf-cm (202.55 - 238.72 ft-lbs)} (Apply LOCTITE#271.)

Tightening torque: 470.7 - 549.2 N·m {4800 - 5600 kgf-cm (347.23 - 405.10 ft-lbs)}

1. HOUSING 2. AXLE SHAFT 3. WHEEL BRAKE 4. BRAKE DRUM 5. OIL SEAL

6. TAPER ROLLER BEARING 7. HUB 8. TAPER ROLLER BEARING 9. ADJUSTMENT NUT 10. LOCK NUT Fig. 3.1 Drive Axle (7 ton)

- 40 -

11. CARRIER 12. CAP 13. SHAFT 14. BALL 15. PLANETARY GEAR

3. DRIVE AXLE

①

②

③ ④

⑤

⑥

⑦

⑧

⑨

⑩

⑪ ⑫ ⑬ ⑭ ⑮ ⑯ ⑰ Tightening torque: 91 - 154 N·m {930 - 1570 kgf-cm (67.11 - 113.59 ft-lbs.)} (Apply LOCTITE#262.)

Tightening torque: 96.1 - 110.8 N·m {980 - 1130 kgf-cm (70.88 - 81.73 ft-lbs.)} (Apply LOCTITE#271.)

Tightening torque: 470.7 - 549.2 N·m {4800 - 5600 kgf-cm (347.23 - 405.10 ft-lbs)}

1. HOUSING 2. AXLE SHAFT 3. WHEEL BRAKE 4. BRAKE DRUM 5. OIL SEAL 6. TAPER ROLLER BEARING

7. HUB 8. TAPER ROLLER BEARING 9. ADJUSTMENT NUT 10. LOCK NUT 11. CARRIER 12. PLANETARY GEAR

Fig. 3.2 Drive Axle (8 ton, 10 ton)

- 41 -

13.

14.

15.

16.

17.

SHAFT BALL SUN GEAR CAP INTERNAL GEAR

3. DRIVE AXLE

3.1.1 DIFFERENTIAL Figure 3.3 shows the construction of the differential where a cross case, ring gear, drive pinion, etc, are installed on the differential carrier. The differential carrier is installed in the axle housing through packings.

The cross case is a separate type in which side gears are engaged with pinions on the spider.

The drive pinion supported by two taper roller bearings, is housed in the bearing cage which is installed on the differential carrier through shims and packings.

The ring gear is a spiral bevel type, which is attached to the cross case with bolts. The ring gear and the drive pinion reduces the rotation from the transmission.

1. ADJUSTMENT NUT 2. CAP 3. LOCK PLATE 4. TAPER ROLLER BEARING 5. PLANE HALF 6. SIDE GEAR 7. PINION GEAR 8. RING GEAR 9. SPIDER 10. THRUST WASHER

11. FLANGE HALF 12. SIDE GEAR 13. THRUST WASHER 14. ROLLER BEARING 15. CARRIER 16. DRIVE PINION 17. TAPER ROLLER BEARING 18. BEARING CAGE 19. "O"-RING 20. SPACER

Fig. 3.3 Differential

- 42 -

21. SHIM 22. TAPER ROLLER BEARING 23. SEAL RETAINER 24. OIL SEAL 25. FLANGE 26. "O"-RING 27. WASHER 28. LOCK NUT 29. pin

3. DRIVE AXLE

3.1.2 FINAL REDUCTION GEAR The final reduction gear is a planetary gear type consisting of a sun gear, planetary pinion gears and an internal gear, and it is installed on both ends of the axle housing. The sun gear is splined onto the axle shaft and locked with a snap ring. The planetary pinion gears are fitted to the shaft inside the planet carrier, which is secured to the wheel hub. The internal gear is splined onto the axle spindle through the hub.

The principle of power transmission is as follows: When the sun gear turns, the rotation is transmitted to the pinion gears and internal gear. However, since the INTERNAL GEAR internal gear is fixed to the spindle, the pinion gears SUN GEAR revolve around the sun gear while spinning SHAFT themselves.

The pinion gears are installed to the carrier which is PINION fixed to the wheel hub, therefore, power of the drive shaft causes the wheel to turn.

Fig. 3.4 Final Reduction Gear

- 43 -

3. DRIVE AXLE

NOTE

- 44 -

4. BRAKE SYSTEM

4. BRAKE SYSTEM Truck model

7 ton

8 ton, 10 ton

Duo-servo type

Two-leading type

(with automatic adjuster) 31.75 mm (1.25 in)

(with manual adjuster) 47.62 mm (1.87 in)

Inner dia. of brake drum

317.5 mm (12.50 in)

438.15 mm (17.25 in)

Lining size

324 x 100 x 10 mm

489 x 100 x 12.7 mm

(12.8 x 3.9 x 0.4 in) 4 x 32400 mm2 (5.022 in2)

(19.3 x 3.9 x 0.5 in) 4 x 48900 mm2 (7.579 in2)

Item Wheel brake Type

Wheel cylinder bore

Lining surface

Parking brake Type

Propeller-shaft braking, internal expansion, mechanical type 160 mm (6.30 in)

Outer dia. of brake drum Lining size

140 x 36 x 3.5 mm

Lining surface

(5.5 x 1.4 x 0.14 in) 50.4 cm2 (0.781 in2)

Brake valve Main valve

Open center type

Emergency valve

Closed center type

Travelling type

Spring type

Inlet flow rate

27 L/min (7.13 U.S. gal/min)

Max. working oil pressure Accumulator

11.8 MPa {120 kgf/cm2 (1706 psi)}

Energy accumulation type

Spring type

Accumulation capacity

66.7 cm3

Accumulator piston Dia.

50 mm (1.97 in)

Stroke

34 mm (1.34 in)

Max. accumulated oil pressure

7.1 MPa {72 kgf/cm2 (1024 psi)}

Switch operating oil pressure

4.8 MPa {49 kgf/cm2 (697 psi)}

Relief oil pressure

12.8 MPa {130 kgf/cm2 (1849 psi)}

- 45 -

4. BRAKE SYSTEM

4.1 GENERAL DESCRIPTION

The brake system is a full power brake type consisting of a brake pedal unit, brake valve, wheel brake and accumulator.

The oil pressure in the brake system is supplied from the 2nd pump of front pump to the brake valve, which converts pedal pressing force into oil pressure and transmits it to the wheel cylinder in the wheel brake.

BRAKE VALVE

STEERING HANDWHEEL

BRAKE PEDAL ACCUMULATOR

PUMP

STEERING CYLINDER

WHEEL BRAKE

Fig. 4.1 Brake System

- 46 -

4. BRAKE SYSTEM

ACCUMULATOR BRAKE PEDAL

BRAKE PEDAL (INCHING)

BRAKE VALVE

134 mm (5.3 in) Free travel: 40 mm (1.6 in)

Fig. 4.2 Brake Pedal

- 47 -

BRAKE LAMP SWITCH

4. BRAKE SYSTEM

4.1.1 BRAKE PEDAL The brake pedal unit is installed at the left side of the frame through a bracket. The brake pedal at the right side presses the piston through the push rod and converts pressing force into oil pressure. The brake pedal at the left side operates the brake valve as the right one does, but it also operates the inching spool in the transmission control valve.

4.1.2 BRAKE VALVE The brake valve has a construction as shown in Figure 4.3. By operating the pedal, the brake valve throttles the oil passage where oil usually flows without resistance, to produce oil pressure.

①

②

④

③

A

B

⑤

⑥

⑦

⑧

⑨

⑩

⑪

C

1. PLUG 2. VALVE SEAT 3. CLOSED VALVE ROD 4. AIR BLEEDER PLUG 5. GUIDE

6. REACTION PISTON 7. SPRING * 8. SPOOL 9. SPRING 10. CUP 11. INPUT PISTON Note * : Not provided on the 8 ton, 10 ton.

Fig. 4.3 Brake Valve

- 48 -

4. BRAKE SYSTEM

The brake valve is operated under the valve open or closed state. Their operating principles are as follows: (1) Operation when the valve opens When the brake pedal is pressed, the input piston moves to the left, and the spring presses the valve spool and the reaction piston to the left against the return spring .

When the valve spool is moved to the left, is closed and the control hydraulic chamber is shut off from the reservoir port. After that, opens so that the controlled oil pressure chamber leads to the pump port.

When the valve spool is further moved to the left from the position shown in step , is throttled to increase the oil pressure at the pump port, so that the oil pressure in the controlled oil chamber and the wheel cylinder increases. The oil pressure in the controlled oil pressure chamber presses the reaction piston to the right, producing pedal pressing force.

A nut comes up against the brake valve body to prevent the oil pressure in the controlled oil pressure chamber from exceeding the maximum adjustment oil pressure when the input piston is operated with the maximum pressing force.

When the pedal is released, the valve spool returns to the original position by the counter force of the reaction piston and the return spring.

(2) Operation when the valve is closed

When the power steering wheel is operated without applying the power brake, the oil pressure at the pump port increases, but the oil pressure in the controlled oil pressure chamber does not increase due to being closed. Therefore, even if the steering wheel is operated without pressing the brake pedal, the brake won't be applied. When the brake pedal is depressed in this state, is closed and opens by the valve spool movement, and the oil flows from the pump port into the braking oil pressure chamber to increase the oil pressure in the wheel cylinder.

(3) Accumulator operation When the pump is not operating (i.e. the engine is shut off), the brake valve operates in the same manner as above, except the following.

The oil pressure in the wheel cylinder does not increase since the oil pressure is not produced at the pump port under the condition described in step of (1).

When the pedal is further pressed in this state shown in step , the valve spool, the reaction piston and the valve rod move to the left as a unit, and the valve rod presses and opens the ball. The controlled oil pressure chamber opens to the accumulator port so that the oil pressure at the accumulator port operates the wheel cylinder.

When the pedal is released, the valve spool, reaction piston and the valve rod move to the right at the same time, and the ball is seated to the valve seat by spring force.

When the ball come in close contact with the valve seat, the valve rod stops at that position. When the reaction piston moves further, and open in this order. When the opens, the oil in the wheel cylinder returns to the reservoir through the controlled oil pressure chamber.

- 49 -

4. BRAKE SYSTEM

4.1.3 ACCUMULATOR The accumulator is used as an emergency energy source when the engine is stopped or the pump becomes defective. The energy accumulation is a spring type. The accumulator has a construction shown in Figure 4.4.

The figure below shows the accumulator storing no energy. At this time, the warning buzzer sounds since the warning switch turned "ON". When the brake pedal or the power steering is operated, and the oil pressure increases to 3.8 MPa {39 kgf/cm2 (555 psi)} or more, the check valve is opened to allow oil to enter the accumulation chamber and the piston presses the spring to accumulate oil.

When the piston moves to the left, the switch rod is moved to the left by the spring and the switch plunger drops into the concave area to turn off the switch. Then, the buzzer is stopped.

When the pump oil pressure increases and the piston moves with a full stroke to touch the stopper, the accumulator has the maximum oil pressure. The oil pressure in this step is 12.8 MPa {130 kgf/cm2 (1849 psi)} and is restricted by the relief valve.

BACK-UP RING ACCUMULATOR SPRING

RELIEF VALVE O"-RING CHECK VALVE PISTON

"O"-RING

WARNING SWITCH

Fig. 4.4 Accumulator

- 50 -

4. BRAKE SYSTEM

4.1.4 WHEEL BRAKE (7 ton trucks) The wheel brake is a duo-servo type and mounted on each end of the drive axle.

The wheel brake consists of two pairs of brake shoes, wheel cylinders and adjusters.

The brake shoe, with one end connected to the anchor of the backing plate and the other to the adjuster, is pressed against the backing plate by both the hold spring and the hold pin.

cre di m n tio ru ta of d o R on ti

Fig. 4.5 Braking Operation in Forward Travel cre di n m tio ru ta f d Ro on o ti

(1) Wheel brake operation As both primary and secondary shoes are forced against the brake drum by the same force, they rotate together with the brake drum until the upper edge of the secondary shoe comes in contact with the anchor.

When the upper edge of the secondary shoe establishes contact with the anchor, the primary shoe presses the secondary shoe by great force created by the wheel cylinder, in addition to by the friction force produced between the brake lining and the brake drum, thus producing a strong braking force (see Figure 4.5).

In reverse travel, the wheel brake works in reverse of that in forward travel (see Figure 4.6).

Fig. 4.6 Braking Operation in Backward Travel

(2) Auto adjuster The auto adjuster automatically the clearance between the brake drum and lining, and consists of the parts shown in Figure 4.7.

The auto adjuster works when the wheel brake is applied in reverse travel.

A

B

Fig. 4.7

- 51 -

4. BRAKE SYSTEM

■ Auto adjuster operation When the wheel brake is operated in reverse travel, the secondary shoe slightly turns together with the brake drum, to turn the lever clockwise around the section A shown in Figure 4.7.

At this time, the lever B turns the adjuster. As the braking force is further increased, the force applied on the adjuster's thread increases to prevent the adjuster from rotating any further.

When the brake is released, the brake shoe returns to the original position while the lever turns counterclockwise around the section A , the section B move down. If one of the adjuster teeth engages with the section B of the lever to adjust the clearance for 0.8 to 1.0 mm (0.03 to 0.04 in.).

Expands in this direction

Fig. 4.8 Automatic Clearance Adjuster (7 ton truck)

(8 ton, 10 ton trucks) The wheel brake is a two-leading type and mounted on each end of the drive axle. The wheel brake consists of two pair of brake shoes, wheel cylinders, and anchor brackets.

Each end of the brake shoe is in contact with the anchor bracket and pressed against the backing plate by the hold pin and nut.

cre di m n io ru at of d t Ro on ti

-

c re di n m tio ru ta f d Ro on o ti

(1) Wheel brake operation As both shoes are forced against the brake drum by the same amount of force by the two wheel cylinders, each shoe turns Fig. 4.9 Braking Operation in

Forward Travel together with the brake drum until it comes in contact with the anchor.

When the shoe establish contact with the anchor, it is pressed by great force created by the wheel cylinder, in addition to by the friction force between the brake lining and drum, thus producing a strong braking force (Figure 4.9).

In reverse travel, the wheel brake works in reverse of that in forward travel.

- 52 -

Fig. 4.10 Braking Operation in Backward Travel

4. BRAKE SYSTEM

①

②

③

④

⑤

⑥ ⑦

⑧ ⑨

⑩ ⑪ ⑫ ⑬

A

B

⑰

⑯

⑮

⑭

View looking from A

1. PRIMARY SHOE 2. RETURN SPRING 3. BOOT 4. CUP 5. PISTON 6. PUSH ROD

View looking from B

7. SECONDARY SHOE 8. UPPER LINK 9. RETURN SPRING 10. TOGGLE LEVER 11. SHOE HOLD DOWN PIN 12. OVER-TRAVEL SPRING

13. ADJUSTER SPRING 14. ADJUSTER LEVER 15. ADJUSTER COVER 16. ADJUSTER 17. SHOE RETURN SPRING

Fig. 4.11 Wheel Brake (7 ton trucks)

- 53 -

4. BRAKE SYSTEM

①

②

③

④

⑤

⑥

⑦

⑧

⑨

⑩ View looking from C

B

C Cross section B - B

B

A

A

⑪

⑫

Cross section A - A

1. PRIMARY SHOE 2. ADJUSTER 3. PUSH ROD 4. PISTON 5. SPRING

6. CUP 7. BOOT 8. SECONDARY SHOE 9. RETURN SPRING 10. BACKING PLATE

11. SHOE HOLD NUT 12. SHOE HOLD PIN

Fig. 4.12 Wheel Brake (8 ton, 10 ton trucks)

- 54 -

4. BRAKE SYSTEM

4.1.5 PARKING BRAKE The parking brake installed on the output shaft in the drive unit is an internal expansion mechanical type.

The lever operating the parking brake is a toggle type. It is installed at the position as shown in Figure 4.13. To release the parking brake, push the release button while pulling the lever.

Release position Operation position

Fig. 4.13 Parking Brake Lever ■ Adjusting lever pulling force (1) Set the lever to the brake release position.

(2) Adjust the lever so that it comes to the position shown in Figure 4.14 when pulling the point B of the lever with force in a range of 29.4 - 49.0N {3 - 5 kgf}. Turn A clockwise to increase the pulling force; turn counterclockwise to decrease.

RELEASE BUTTON

A

B

C

View looking from C

Fig. 4.14

- 55 -

4. BRAKE SYSTEM

4.2 MAINTENANCE

4.2.1 CHECKING WHEEL BRAKE Check the disassembled parts, replacing any defective parts with new ones.

(1) Check the inside of the wheel cylinder and the outer periphery of the piston for corrosion, replacing any defective parts with new ones.

Then, measure the clearance between the piston and cylinder.

Standard: 0.03 - 0.10 mm (0.0012 - 0.004 in) Limit: 0.126 mm (0.005 in)

Fig. 4.15 (2) Visually check the piton cup for damage or deformation, replacing any defective part with a new one.

(3) Measure the load of wheel cylinder spring and if the measurement is out of the standard value, replace the spring with a new one.

Truck model

Item

Load (N{kgf}/setting size)

7 ton

8 ton, 10 ton

15.7±1.96 {1.6±0.2}/14 mm (0.55 in)

333.4±3.92 {34±0.4}/20 mm (0.787 in)

33.5 mm (1.32 in)

65.9 mm (2.59 in)

Free length*

Note *: Reference value (4) Measure the thickness of the brake lining and replace any lining worn beyond the limit with a new one.

Unit: mm (in) Truck model

7 ton

8 ton, 10 ton

Standard value

10 (0.39)

12.5 (0.49)

Limit

1 (0.04)

1 (0.04)

Item

Fig. 4.16

- 56 -

4. BRAKE SYSTEM

(5) Visually check the inner surface of the brake drum, and if any damage or uneven wear is found, correct by grinding. A brake drum which shows wear beyond the limit should be replaced with a new one.

Unit: mm (in) Truck model 7 ton 8 ton, 10 ton Item Standard value

317.5 (12.50)

438.15 (17.25)

Limit

319.5 (12.58)

440.15 (17.33)

Fig. 4.17

(6) Measure the free length and setting load of the shoe return springs and replace any shoe return spring which shows measurements far beyond the standard values, with a new one.

Item

Truck model

7 ton

8 ton, 10 ton

Primary side 294.2 ± 29.4 Adjustment side

{30 ± 3}/101.2 (3.98) Load N{kgf}/ length mm(in)

Secondary side 245.2 ± 24.5 Anchor side

{25 ± 2.5}/101.2 (3.98)

Free length mm (in)

Primary side

90 (3.54)

Adjustment side

Secondary side

93 (3.66)

Anchor side

411.9 ± 39.2 {42 ± 4}/159 (6.26) 490.3 ± 49.0 {50 ± 51}/178 (7.01) 148 (5.83) 169.5 (6.67)

(7) Check the adjuster for damage, rotation, and the engagement of the pole lever and the teeth, and if any defect is found, replace the adjuster with a new one.

When reinstalling the adjuster without replacement, clean and apply grease (Akebono Brake AKB100 or equivalent) (7 ton truck only) (8) Measure the free length of the spring and link assembly.

Standard free length: 99.0 mm (3.90 in)

99.0 mm (3.90 in)

Fig. 4.18

- 57 -

4. BRAKE SYSTEM

4.2.2 REASSEMBLING WHEEL BRAKE (7 ton trucks) (1) Apply brake fluid on the cup and piston of the wheel cylinder and reinstall the spring, piston cup, piston and boot in that order.

(2) Reinstall the wheel cylinder on the backing plate.

Bolt torque: 17.7 - 26.5 N-m {180-270 kgf-cm (13- 19.5 ft-lbs)} (3) Reinstall the backing plate on the front axle.

Bolt torque: 117.7 - 137.3 N-m {1200 - 1400 kgf-cm (86.8 - 101.3 ft-lbs)} (4) Apply heat-resistant grease (Akebono Brake AKB100 or equivalent) to the points shown in Figure 4.19, using caution not to contaminate the lining with grease.. (a) Backing plate shoe ledge surface (6 points) (b) (b) (b) Anchor (4 points) ·Fitting part of adjuster and shoe web (2 points) (a) (a) (c) Contact part of shoe hold-down cup and shoe web (2 points) ·Hole in toggle lever (3 points) (a)

(a) (c)

(c)

(a)

(a) (b)

(b)

Fig. 4.19 (5) Reinstall the shoe with the hold-down spring.

Hand tool

Fig. 4.20

- 58 -

4. BRAKE SYSTEM

(6) Reinstall the shoe guide pin on the anchor, and then reinstall the shoe return spring. At this time, reinstall the primary side (painted in white) first, and then reinstall the secondary side.

Hand tool

Fig. 4.21 (7) Reinstall the spring, adjuster, adjuster spring, and adjuster lever, observing the following conditions: ① The adjuster's left thread goes to the left-side brake while its right thread goes to the right-side brake. ② The adjuster's teeth should not make contact with the spring. ③ When installing the adjuster-side shoe return spring, the one with a longer hook should go to the adjuster lever side. ④ After reassembly, make sure the front edge of the adjuster lever is in contact with the adjuster teeth.

Fig. 4.22

(8) Reinstall the brake pipe on the wheel cylinder.

(9) Measure the inner diameter of the brake drum and adjust the outer diameter of the shoe. Adjust with the adjuster to ensure that the diameter of the brake shoe to the following value.

Brake shoe outer diameter (mm) = Drum inner diameter (mm) – 1.0 mm

Fig. 4.23

- 59 -

4. BRAKE SYSTEM

4.2.3 TESTING AUTOMATIC ADJUSTER FOR OPERATION (7 ton trucks) (1) Adjust the brake shoe's outer diameter to nearly the normal setting length, push up the adjuster lever to turn the adjuster teeth. When your fingers are released, the adjuster lever returns to its original position with the adjuster teeth remaining as they are.

Note: Even if the adjuster teeth return along with the lever, they will be properly adjusted after the adjuster is installed on the truck.

(2) If the adjuster won't operate by pushing the adjuster lever in the direction indicated by the arrow, follow the procedure given below. (a) Check whether the adjuster lever, adjuster, adjuster spring, over-travel spring, upper link and shoe return spring are properly installed. (b) Check the springs for deterioration, the adjuster for rotation and damaged teeth, the contact parts of the adjuster lever and teeth for damage. If any defect is found, replace the defective part with a new one.

UPPER LINK TOGGLE LEVER OVER-TRAVEL SPRING

SHOE RETURN SPRING

ADJUSTMENT LEVER

ADJUSTER

Fig. 4.24

- 60 -

4. BRAKE SYSTEM

4.2.4 ADJUSTING BRAKE PEDAL (1) Make the brake valve's push rod short.

(2) Adjust the pedal height with the stopper bolt as shown in Figure 4.25.

(3) With the pedal pressed by the free travel, extend the push rod to let the push rod end contact the brake valve piston.

(4) Tighten the push rod lock nut.

134 mm (5.28 in) PLAY: 40 mm (1.58 in)

PUSH ROD

A

PEDAL STOPPER BRAKE LAMP SWITCH

BRAKE VALVE

BRAKE SWITCH

LOCK NUT

Fig. 4.25 ■ Adjusting brake switch (1) Make sure the brake pedal height is the value shown in Figure 4.25, and then loosen the brake switch lock nut.

(2) Disconnect the brake switch lead wire from the connector.

(3) Turn the switch and adjust the size of part A to 1mm (0.04 in).

(4) Make sure the brake lamp comes on when the brake pedal is pressed by the free travel.

- 61 -

4. BRAKE SYSTEM

4.2.5 ADJUSTING INCHING AND BRAKE PEDALS Press the inching pedal and brake pedal to check if the pedal can be pressed smoothly and returns securely.

Check the brake pedal and inching pedal for play as shown in Figure 4.26.

The pedal play B is as follows: Unit: mm (in) Inching pedal

Brake pedal

Pedal upheight A

Play B

Pedal upheight A

Play B

134 (5.28)

40 (1.58)

134 (5.28)

40 (1.58) Fig. 4.26

4.2.6 ADJUSTING CLEARANCE BETWEEN LINING AND DRUM (8 ton, 10 ton trucks) 1. Remove the adjuster cover from the back plate.

2. Turn the adjuster teeth (2 points) from inside to outside to let the lining contact the drum.

3. Back off 5 to 6 notches of the adjuster teeth. This adjusts the clearance to 0.75 - 0.90 mm (0.03 0.035 in).

COVER

Cross section A - A

Expansion View looking from B

Fig. 4.27 - 62 -

4. BRAKE SYSTEM

4.2.7 TROUBLESHOOTING Problem

Probable cause

Poor braking force

Noise in braking operation

Uneven braking action

Remedy

1. Brake fluid leaks from brake system

Repair

2. Improperly adjusted shoe clearance

* Check and adjust adjuster.

3. Overheated brake

Check for dragging.

4. Improper contact between drum and lining

Adjust contact properly.

5. Foreign matter on lining

Repair or replace.

6. Foreign matter mixed in brake fluid

Check brake fluid.

7. Improperly adjusted pedal height

Adjust properly.

1. Hardened lining surface or foreign matter on lining surface

Repair or replace.

2. Deformed backing plate or worn ledge

Repair or replace.

3. Deformed shoe or improper installation

Repair or replace.

4. Unevenly worn lining

Replace.

5. Defective wheel bearing

Replace.

1. Foreign matter on lining

Repair or replace.

2. Improperly adjusted brake shoe clearance

* Check and adjust adjuster

3. Malfunction of wheel cylinder

Repair or replace.

4. Defective shoe return spring

Replace.

5. Eccentric drum or defective sliding surface

Repair or replace.

6. Improper tire inflation pressure

Adjust

* How to determine whether the brake shoe clearance is correct or not.

1. Shut down the engine.

2. Pump the brake pedal several times until the accumulator warning buzzer sounds.

Truck model

7 ton

8 ton, 10 ton

Normal

8 - 12 times

4 - 6 times

Abnormal

less than 6 times

less than 3 times

Item

- 63 -

4. BRAKE SYSTEM

NOTE

- 64 -

5. STEERING SYSTEM

5. STEERING SYSTEM Truck model

Item

7 ton

Type

8 ton

10 ton

Rear-wheel steering with power steering

Steering gear box Type

Semi-integral type

Name Reduction ratio

20.0

Working angle

70°

Ball screw direction

Left

Maximum oil pressure

11.8 MPa {120 kgf/cm2 (1706 psi)}

Maximum flow rate

27 L/min (7.1 U.S. gal/min)

Power cylinder Type

Double-acting piston

Cylinder bore

71 mm (2.795 in)

Rod diameter

30 mm (1.181 in)

Stroke

335 mm (13.189 in)

Steering axle Type

Center-pin supported, elliot type

Steering angle Inner wheel

79°

Outer wheel

50°

King pin spacing Swivel radius

1500 mm (59.055 in) 42 mm (1.654 in)

45 mm (1.772 in)

←

←

8.25 x 15 x 14PR(I)

9.00 x 20 x 14PR(I)

←

J-LUG

←

←

Rim size

6.50T x 15

7.00T x 20

←

The inflation pressure

0.79 MPa

0.74 MPa

←

{8.0 kgf/cm (113.8 psi)}

{7.5 kgf/cm (92.4 psi)}

Camber

54 mm (2.126 in) 1°

Wheel Wheel size Tread pattern

2

2

Note: For the orbitrol type steering system, see Chapter 8.

5.1 GENERAL DESCRIPTION

The steering system is a rear-wheel steering type with power steering, consisting primarily of a steering wheel, a steering gear box, a power cylinder, and a steering axle.

- 65 -

5. STEERING SYSTEM

5.1.1 STEERING WHEEL UNIT The steering wheel unit is arranged as shown in Figure 5.1. It consists of a steering wheel, steering shaft and steering gear box. The steering shaft is connected to the steering gear box through a universal joint. The steering column supporting the steering shaft can be tilted back and forth to a certain extent.

STEERING WHEEL

LOCK LEVER

STEERING SHAFT STEERING GEAR BOX

UNIVERSAL JOINT

Fig. 5.1 Steering Wheel Unit 5.1.2 STEERING GEAR BOX The steering gear box is a semi-integral type which consists of a combination of a ball nut type worm gear shaft and a control valve.

In the screw grooves between the ball nut and worm shaft are steel balls which recirculate as the worm shaft rotates, thus providing smooth, easy action of the steering wheel. The threaded area of the ball nut is in mesh with the threaded area of the sector shaft to convert linear motion of the ball nut into rotating motion of the sector shaft.

The sector shaft is supported through bushings by the gear box and the side cover and has an adjustment screw at the side cover side to adjust the engagement of the gears.

Under the bottom of the gear box is a control valve consisting of a housing, a spool, a spring and a reaction piston. The spool is fitted to the worm shaft with nuts. The power cylinder oil flow is controlled by switching over the oil grooves in the control valve housing and those in the spool.

- 66 -

5. STEERING SYSTEM

Tightening torque: 20 - 29 N·m {200 - 300 kgf-cm (14.5 - 21.7 ft-lbs)}

Apply grease: 3g

Tightening torque: 34 - 53 N·m {350 - 540 kgf-cm (25.3 - 39.1 ft-lbs)}

Tightening torque: 34 - 53 N·m {350 - 540 kgf-cm (25.3 - 39.1 ft-lbs)}

Cross section A - A

Tightening torque: 37 - 57 N·m {380 - 580 kgf-cm (27.5 - 42.0 ft-lbs)}

1. WORM GEAR 2. TOP COVER 3. OIL SEAL 4. RADIAL BEARING 5. "O"-RING 6. BALL NUT 7. RADIAL BEARING 8. PISTON 9. SPRING 10. "O"-RING 11. PISTON

12. THRUST RACE 13. THRUST BEARING 14. NUT 15. END COVER 16. SPOOL 17. SPRING 18. HOUSING 19. "O"-RING 20. THRUST RACE 21. THRSUT BEARING 22. PACKING

Fig. 5.2 Steering Gear Box

- 67 -

23. NUT 24. LOCK NUT 25. SIDE COVER 26. "O"-RING 27. BUSHING 28. SHIM 29. ADJUSTMENT SCREW 30. RADIAL BEARING 31. OIL SEAL 32. SNAP RING 33. SECTOR SHAFT

5. STEERING SYSTEM

(1) Steering wheel in straight position When the steering wheel in straight position, the spool ④ is in the position shown in Figure 5.3 by operation of the centering spring ③ . At this time, the gaps A, B, C and D are equal in size, and the oil from the pump flows through the control valve, back into the tank.

①

②

③ ④

⑤

Fig. 5.3 Neutral (2) When steering wheel is turned counterclockwise When the steering wheel is turned counterclockwise, the ball nut ① applies force to the sector shaft. Due to resistance of the truck body, the sector shaft won't rotate and the worm shaft ② shifts downward instead. Along with this, the spool ④ also moves downward, closing the gaps A and C while widening B and C. The oil from the pump thus flows through the gap B to the tail side of the power cylinder. On the other hand, the oil returning from the power cylinder cap passes through the gap D, back into the tank. The above operation continues while the steering wheel is being turned. When the rotation of the steering wheel is discontinued, the worm shaft ② is returned to the original position by the centering spring ③ , thus putting the gaps A, B, C, and D in neutral.

Downward

Fig. 5.4 Counterclockwise Rotation

- 68 -

5. STEERING SYSTEM

(3) When steering wheel is turned clockwise When the steering wheel is turned clockwise, the worm shaft ② moves upward, closing the gaps, B and D while widening A and C, so that the oil from the pump flows through the gap C to the power cylinder cap. The oil returning from the power cylinder tail flows through the gap A into the tank. The subsequent operation is the same as described in step (2).

Upward

Fig. 5.5 Clockwise Rotation

5.1.3 POWER CYLINDER The power cylinder is a double-acting piston type, the cylinder tail being fitted to the frame and the rod side to the steering axle center arm.

The power cylinder is controlled by the control valve in the steering gear box. When the steering wheel is turned counterclockwise, oil pressure is applied to the cylinder tail side and when the steering wheel is turned clockwise, it is applied to the cylinder cap side.

①

②

③

1. BALL JOINT 2. NUT 3. PISTON 4. PACKING

④

⑤

⑥

⑦ ⑧ ⑨

⑩

5. CYLINDER 6. ROD 7. "O"-RING 8. BUSHING

Fig. 5.6 Power Cylinder

- 69 -

⑪

⑫

9. CAP 10. PACKING 11. PACKING 12. BALL JOINT

5. STEERING SYSTEM

5.1.4 STEERING LINKAGE The steering linkage consists of a drag link and a power cylinder, as shown in Figure 5.7. The drag link feeds back movement of the power cylinder to the sector shaft of the steering gear box.

POWER CYLINDER

Tightening torque: 245.2 - 294.2 N·m {2500 - 3000 kgf-cm (180.9 - 217.0 ft-lbs)}

55 mm (2.17 in)

60 mm (2.36 in)

DRAG LINK

STEERING GEAR BOX Tightening torque: 107.9 - 147.1 N·m {1100 - 1500 kgf-cm (79.6 - 108.5 ft-lbs)} [2 locations] Tightening torque: 186.3 - 280.5 N·m {1900 - 2860 kgf-cm (137.4 - 206.9 ft-lbs)} [2 locations]

Tightening torque: 245.2 - 294.2 N·m {2500 - 3000 kgf-cm (180.9 - 217.0 ft-lbs)}

Fig. 5.7 Steering Linkage

- 70 -

5. STEERING SYSTEM

5.1.5 STEERING AXLE The steering axle is an Elliot type consisting of a center arm at the center, knuckles at both opposite ends, and tie rods which transmit movement of the center arm.

The ball joins at the opposite ends of each tie rod have threads at the center arm side and right-hand threads at the knuckle side.

① ② ③ ④ ⑤ ⑥

⑦ ⑧ ⑨ ⑩ ⑯ ⑮ ⑭

⑬⑫

⑪ Details of king pin

1. OIL SEAL 2. TAPER ROLLER BEARING 3. HUB 4. TAPER ROLLER BEARING 5. ADJUSTMENT NUT 6. LOCK NUT

7. CAP 8. BEARING 9. BEARING 10. KING PIN 11. BEARING 12. KNUCKLE

Fig. 5.8 Steering Axle

- 71 -

13.

14.

15.

16.

LOCK PIN AXLE TIE ROD CENTER ARM

5. STEERING SYSTEM

(1) Knuckle and king pin The knuckle is supported with a king pin which in turn is secured at the knuckle side with a lock pin.

The top and bottom of the king pin are fitted to the axle boss with needle bearings.

Between the axle boss and the knuckle is a thrust bearing to let the knuckle smoothly rotate around the king pin, sustaining load.

The needle bearings and thrust bearing are lubricated by grease supplied through the grease fittings at top and bottom of the king pin.

LOCK PIN

KING PIN

THRUST BEARING OIL SEAL KNUCKLE

NEEDLE BEARING

Fig. 5.9 Knuckle (2) Wheel hub The wheel hub is mounted on the knuckle spindle with two taper roller bearings and its preload is adjusted with a nut.

- 72 -

5. STEERING SYSTEM

5.2 MAINTENANCE

5.2.1 DISASSEMBLING STEERING GEAR BOX (1) Hold the steering gear box in a vise.

Fig. 5.10 (2) Remove the box nut and packing from the adjustment screw. Remove the side cover mounting bolts and turn the adjustment screw clockwise. This causes the side cover to come off.

Note: Exercise care not to lose the "O"-ring fitted to the side cover.

Remove the adjustment screw and shims fitted to the sector shaft.

Fig. 5.11 (3) Rotate the worm shaft so that the sector shaft teeth are positioned as shown in Figure 5.12.

Lightly tapping the sector shaft serration by hand, remove the sector shaft.

Fig. 5.12 (4) Remove the bolts securing the end cover and detach the end cover, using caution not to lose the "O"-ring.

Fig. 5.13

- 73 -

5. STEERING SYSTEM

(5) Install the disassembly jig (Figure 5.15) as shown in Figure 5.14.

Straighten the tang of the lock nut with use of a screwdriver and remove the lock nut. Then remove the thrust race and thrust bearing.

Fig. 5.14 Unit: mm (in)

Thickness: 3 (0.1)

Fig. 5.15 (6) Loosen the three bolts alternately in such a way that the disassembly jig does not incline. Remove the bolts, supporting the control valve by hand, with care not to allow the control valve and reaction piston to drop.

Fig. 5.16 (7) Remove the top cover fitting bolts and take off the top cover by lightly prying it with use of a screwdriver. Use caution not to damage "O"-ring.

Fig. 5.17

- 74 -

5. STEERING SYSTEM

(8) Carefully remove the ball nut assembly from the gear box. Keep the ball nut horizontal at all times. Failure to do so will damage the ball scooping area, resulting in the malfunction of the ball nut assembly.

Fig. 5.18 5.2.2 INSPECTION Clean all the disassembled metal parts in cleaning oil and prepare new "O"-rings and oil seals. After cleaning, inspect all parts for scratches or scores, wear or cracks. Put them in a place free from dust and dirt until reinstallation.

(1) Replace the "O"-rings and oil seals with new ones. Check the side cover bushings for damage or wear, replacing any defective ones.

(2) Operate the ball nut assembly to see if it is operating normally. If not, clean it, slowly operating in cleaning oil. Replace the ball nut assembly when the threaded grooves show sign of flaking, dent, or undue wear.

(3) Inspect the sector shaft for evidence of excessive scores on the gear teeth or undue wear on the shaft.

Replace the sector shaft if defective.

(4) Inspect the radial bearing and side cover bushing in the gear box assembly to see if they are excessively worn. Replace if necessary.

(5) Inspect the radial bearing inside the top cover for defect. Replace if necessary.

(6) Inspecting the control valve ① Inspect the valve housing inner surface, especially the orifice areas for sign of battering or damage. If unsatisfactory, replace the control valve assembly. ② Inspect the spool diameter and orifice areas for sign of battering and damage. If unsatisfactory, replace the spool. ③ Inspect the spring for cracks or breakage, replacing the spring if defective. ④ Check whether the reaction piston is sliding smoothly inside the valve housing. If unsatisfactory, replace the valve assembly.

- 75 -

5. STEERING SYSTEM

5.2.3 REASSEMBLING STEERING GEAR BOX (1) Reassembling control valve ① Install the spool in the valve housing, matching the "P" mark on the housing with the smaller chamfered diameter of the spool. ② Install the reaction piston and center spring in the valve body.

Fig. 5.19

Fig. 5.20 (2) Hold the gear case in a vise and apply grease on the oil seal inside the gear case.

Fig. 5.21 (3) Install the ball nut assembly in the gear case, with the rack gear upward.

Fig. 5.22

- 76 -

5. STEERING SYSTEM

(4) Fill the oil seal with grease and apply a thin coat of grease on the "O"-ring at the gear case in the top cover fitting area. Slowly insert the column through the gear box. Forceful insertion might damage the "O"-ring.

Tightening torque: 34.3 - 53.0 N·m

{350 - 540 kgf-cm

(25 - 40 ft-lbs)} Fig. 5.23 (5) Install the thrust race, needle bearing and thrust race onto the worm shaft.

Fig. 5.24 (6) Install the control valve assembly on the gear case, being careful not to allow the reaction piston to drop. Make sure that the "O"-ring of the gear case is securely settled in the groove.

Fig. 5.25 (7) Install the jig shown in Figure 5.15 on the control valve. Then install the thrust race, needle bearing and thrust race in that order.

Fig. 5.26

- 77 -

5. STEERING SYSTEM

(8) Rotate the worm shaft counterclockwise to stop and hand tighten the nut until thrust bearing has no clearance, and mark the groove position in the shaft on the lock nut. Back off lock nut and check to see if the marked position remains unchanged.

If satisfactory, retighten the lock nut about 5°.

Shaft rotating torque: 0.98 N·m {10 kgf-cm

(72 ft-lbs)} or less Fig. 5.27 (9) Caulk the lock nut.

Fig. 5.28 (10) Install the "O"-ring in the groove of the end cover and attach the end cover.

Tightening torque: 37.3 - 56.9 N·m

{380 - 580 kgf-cm

(27.5 - 42.5 ft-lbs)}

Fig. 5.29 (11) Install the ball nut assembly so that the center of the rack gear is aligned with the center of the side cover fitting window.

Fig. 5.30

- 78 -

5. STEERING SYSTEM

(12) Install the sector shaft on the gear case. Install the adjustment screw and shims in the sector shaft groove, and match the side cover screw hole with the adjustment screw. Install the side cover, turning the adjustment screw. At the same time, install an "O"-ring into the groove in the side cover.

Tightening torque: 34.3 - 53.0 N·m

{350 - 540 kgf-cm

(25.3 - 39.1 ft-lbs)}

Fig. 5.31

(13) Set the pitman arm in the middle of the whole rotating angle of the worm shaft. Set a dial gauge at a position 150 mm (5.9 in) away from the pitman arm center and measure for looseness.

Looseness: below 0.3 mm (0.0118 in)

Fig. 5.32

If there is a looseness of more than 0.3 mm (0.0118 in), adjust with the adjustment screw.

After adjustment, install the packing and secure with lock nut. Finally, install the box nut.

Tightening torque: 19.6 - 29.4 N·m

{200 - 300 kgf-cm

(14.5 - 21.7 ft-lbs)}

Fig. 5.33 (14) Rotate the worm shaft to count the number of turns from stop to stop.

Total number of turns: 4 2 turns

3 (15) Rotate the worm shaft clockwise or counterclockwise to stop and release it. Make sure it returns about 50° smoothly.

- 79 -

5. STEERING SYSTEM

5.2.4 ADJUSTING PRE-LOAD OF WHEEL BEARING (1) As shown in Figure 5.34, apply grease (amount: 80% of space capacity) on the hub, inner bearing, outer bearing and cap. Also apply grease on the lip of the oil seals.

(2) Set bearings on the hub and install the hub on the knuckle spindle.

(3) Install the plain washer and tighten the adjustment nut to the torque of 206.0 - 235.4 N·m {21 - 24 kgf-m (152 - 174 ft-lbs)}. Back off the adjustment nut then retighten to the torque of 9.8 N·m {1 kgf-m (7.2 ft-lbs)}.

(4) Lightly tapping the hub with a wooden hammer, rotate the hub 3 to 4 turns to make certain there is no looseness.

(5) Tighten the adjustment nut to the position which allows the cotter pin to be set.

(6) Tapping the hub with a wooden hammer, rotate the hub 3 to 4 turns to secure smooth rotation and measure the starting torque.

Starting torque: 2.94 - 7.85 N·m {0.3 - 0.8 kgf-m (2.2 - 5.8 ft-lbs)} (7) When the starting torque is other than the specified, replace the plain washer and adjustment nut.

Repeat the operations described in step (3) and after to obtain the specified starting torque.

(8) Lock the adjustment nut with the cotter pin.

Apply grease (amount: 80% of space)

Apply grease (amount: 80% of space)

Fig. 5.34 Preload Adjustment

- 80 -

5. STEERING SYSTEM

5.2.5 TROUBLESHOOTING GUIDE Problem

Steering wheel won't operate.

Hard steering wheel

Truck wanders or vibrates.

Noisy operation

Oil leaks

Possible cause

Remedy

Defective or damaged pump

Replace.

Relief valve stuck or damaged

Clean or replace.

Control valve stuck, damaged or worn

Replace or repair.

Damaged hose joint or clogged oil line

Replace or clean.

Low oil level in oil tank

Add oil.

Insufficient air bleeding

Bleed air.

Low pressure

See preceding item.

Control valve stuck or damaged

Clean or replace.

Loose control valve spool

Retighten lock nut.

Damaged control valve

Replace.

Broken or deteriorated spring

Replace.

Low oil level in oil tank

Add oil

Clogged suction pipe or filter

Clean or replace.

Control valve stuck or damaged

Replace.

Improperly-installed or damaged "O"-ring or oil seal for piping or control valve.

Replace.

- 81 -

5. STEERING SYSTEM

NOTE

- 82 -

6. HYDRAULIC SYSTEM

Truck model

Item Main pump Type Model

Discharge

6. HYDRAULIC SYSTEM 7 ton

8 ton

10 ton

Gear type Front: SDY1-363.5R525 Rear: SGP2-44L551 Front: 36.6 cm3/rev + 3.38 cm3/rev Rear: 44.7 cm3/rev

← ← ← ← ←

← ← ← ← ←

Control valve Type Model Pressure setting Main Steering Lift cylinder Type Cylinder bore Stroke Tilt cylinder Type Cylinder bore Rod diameter Stroke Oil tank Capacity

2-spool sliding type, with relief valve, flow divider, and tilt lock KVS-120VPF 19.6 MPa {200 kgf/cm2 (2845 psi)} 11.8 MPa {120 kgf/cm2 (1707 psi)}

← ←

← ←

Single-acting piston 80 mm (3.15 in) 1495 mm (58.86 in)

← 90 mm (3.54 in) ←

← 100 mm (3.94 in) ←

Double-acting piston 115 mm (4.53 in) 50 mm (1.97 in) 227 mm (8.94 in)

← ← ← 242 mm (9.53 in)

← ← ← ←

60 L (15.85 U.S. gal)

←

70 L (19.8 U.S. gal)

6.1 GENERAL DESCRIPTION

The hydraulic system consists of a main pump, a control valve, lift cylinders and tilt cylinders. The oil is supplied from the tank at the right of the frame.

- 83 -

6. HYDRAULIC SYSTEM

6.1.1 FRONT PUMP Note: For the front pump of trucks whose serial number is lower than those shown in Figure 6.1, refer to "6.1.2 REAR PUMP" on the next page. Its operation is the same as that of the 1st pump in this paragraph.

The front pump is a double gear pump and driven by the PTO device of the transmission. The 1st pump sends oil from the oil tank to the control valve while the 2nd pump sends oil to the accumulator of the brake system.

The design of the front pump as shown below.

1. DRIVE GEAR (1ST) 2. SNAP RING 3. OIL SEAL 4. GASKET 5. SIDE PLATE 6. VALVE BODY 7. DRIVE GEAR (2ND)

8. BUSHING 9. VALVE BODY 10. 3-LETTER GASKET 11. SIDE PLATE 12. DRIVEN GEAR (2ND) 13. GASKET 14. STEEL BALL

Fig. 6.1 Front Pump

- 84 -

15. ADAPTER PLATE 16. DRIVEN GEAR (1ST) 17. 3-LETTER GASKET 18. BUSHING 19. FRONT COVER.

6. HYDRAULIC SYSTEM

6.1.2 REAR PUMP The rear pump is a gear pump which is driven by the PTO device of the transmission. It pick up oil from the oil tank and sends it to the control valve.

1. DRIVE GEAR 2. SNAP RING 3. FRONT COVER 4. OIL SEAL

5. VALVE BODY 6. SIDE PLATE 7. REAR COVER 8. DRIVEN GEAR

Fig. 6.2 Rear Pump

- 85 -

9. GASKET/BACK-UP STRIP 10. GASKET 11. BUSHING

6. HYDRAULIC SYSTEM

6.1.3 CONTROL VALVE The control valve consists of an inlet section, 2 types of plunger sections and an outlet section, all of which are assembled with three bolts.

LIFT PLUNGER

MAIN RELIEF VALVE

PF GAUGE PORT (PT1/8)

PS RELIEF VALVE

TILT PLUNGER

LIFT PLUNGER

Fig. 6.3 Control Valve (7 ton trucks)

- 86 -

TILT PLUNGER

6. HYDRAULIC SYSTEM

MAIN RELIEF VALVE

LIFT PLUNGER

PORT RELIEF VALVE

TILT PLUNGER

PF GAUGE PORT (PT1/8)

PS RELIEF VALVE

TILT PLUNGER

LIFT PLUNGER

Fig. 6.4 Control Valve (8 ton, 10 ton trucks)

- 87 -

6. HYDRAULIC SYSTEM

■ Control valve operation (1) Inlet section

As shown on Figure 6.5, the inlet section has a relief valve which regulates the steering circuit oil pressure, and a flow divider which divides the oil flow from the main pump into two lines: load handling and steering. The inlet section also has a cartridge type main relief valve which sets the load handling circuit oil pressure.

SPRING (B)

PORT P

PORT T CONTROL ORIFICE (G) CHECK VALVE (C)

SPOOL (A)

MAIN RELIEF VALVE (D)

PS RELIEF VALVE (E)

DUMPER ORIFICE (I) METERING ORIFICE (H)

Fig. 6.5 Inlet Section ■ Flow divider operation (a) Pump discharge is smaller than preset flow rate

The oil flows, passing through port P, oil passage (J) and orifice (G) to port PF. Part of the oil passing through oil passage (J) flows through oil passage (K) to the plug side of the spool (A). Part of the oil passing through orifice (G) flow through orifices (H) and (I) to the spring side (B) of the spool (A), but the pressure differential across the orifice (G) is smaller than the force of the spring (B), and thus the part (M) of the spool (A) is kept closed so that all the oil flows to the PF side.

PF

- 88 -

Fig. 6.6

Discharge is smaller than the preset flow rate

6. HYDRAULIC SYSTEM

(b) Pump discharge is greater than preset flow rate

When the pump discharge is greater than the preset flow rate, the pressure differential across the orifice (G) increases to move the spool (A) the right so that the part (M) is opened to allow excess oil to flow to the EF side. If the PF side circuit actuates and the pressure in the circuit rises, the spool (A) automatically shift so that the opening of the part (M) becomes smaller, thus striking a balance to attain the specified working pressure and flow rate.

PF

Fig. 6.7

Discharge is greater than preset flow rate

(c) Actuation EF side circuit (EF: load handling circuit)

When the EF circuit is actuated enough to increase the oil pressure and the pressure differential across orifice (G) becomes greater, the spool (A) moves to the right, narrowing the opening of the part (N) to prevent the amount of more than the preset flow rate to flow to the PF side. (d) Simultaneous actuation of both PF and EF circuits (PF: steering circuit)

When the pressure in both the PF and EF circuits increase simultaneously, the opening at the part (M) of the spool (A) is automatically determined so that the flow rate be kept constant. (e) When PF circuit pressure reaches relief pressure

When the PF circuit pressure increase enough to actuate the relief valve (E), the oil flows into the oil tank at the flow rate determined by orifice (H) and the flow of oil to the EF side increases accordingly.

- 89 -

6. HYDRAULIC SYSTEM

■ Operation of main relief valve (a) The oil in the high-pressure passage HP flows through the oil hole in the piston C to affect the two areas A and B which are different in diameter, so that the poppets D and K are securely seated.

Fig. 6.8 (b) When the pressure in the high-pressure passage HP reaches the setting pressure of the pilot spring, the pilot poppet E opens. The oil passes around the poppet, flows through the drilled hole to the low-pressure side LP.

Fig. 6.9 (c) As the pilot poppet E is opened, the pressure behind the poppet D drops. As compared to the pressure becomes unbalanced, causing the poppet D to open and thereby sending the oil directly to the low-pressure passage LP.

Fig. 6.10 (d) When the pressure in the high-pressure passage HP is lower than that in the low-pressure passage, the poppet D opens due to the difference between the areas A and B , allowing enough oil from the low-pressure passage LP to the high-pressure passage HP.

Fig. 6.11

- 90 -

6. HYDRAULIC SYSTEM

(2) Plunger section There are two plunger sections, one for the lift circuit and one for the tilt circuit. Their construction is shown in Figure 6.12.

The plunger is attached to the housing and is kept in neutral by the return spring. The configuration of the lift circuit plunger is different from that of the tilt circuit plunger.

LOAD CHECK VALVE PARALLEL FEEDER CYLINDER PORT A

CYLINDER PORT B

RETURN SPRING

PLUNGER NEUTRAL PASSAGE

LOW-PRESSURE PASSAGE

Fig. 6.12 Plunger Section

■ Operation of plunger (a) Neutral

Oil discharge from the main pump flows through the neutral passage back to the oil tank. (b) Pushing in of plunger

The neutral passage is closed and the oil flows through parallel feeder, pushing up the load check valve, into the cylinder port B. The oil returning from the cylinder port A flows through the lowpressure passage to the tank. The plunger is restored to the neutral position by the return spring.

- 91 -

PORT B

PORT A

Fig. 6.13 Pushing in of Plunger

6. HYDRAULIC SYSTEM

(c) Drawing out of plunger

With the neutral passage closed, the oil pushes up the load check valve, passing through the parallel feeder, and flows into the cylinder port A. The oil returning from the cylinder port B flows through the low-pressure passage to the tank. The plunger is restored to the neutral position by the return spring.

PORT A

PORT B

Fig. 6.14 Drawing out of Plunger ■ Operation of the tilt lock valve (a) Drawing out of plunger

When the plunger is drawn out, the oil flows in the same manner as in Figure 6.14. Figure 6.15 shows a plunger section with a tilt lock valve in neutral.

TILT CYLINDER

SPRING

POPPET

PLUNGER

Fig. 6.15 Neutral (b) Pushing in of plunger (pump in operation)

The oil from the main pump flow through the port B to the tilt cylinders. The oil returning from the cylinders flows through the oil hole A on the plunger to actuate the poppet. This allows the oil to pass through the plunger holes A and B to the low-pressure passage and back to the tank.

PORT A

PORT B

PLUNGER

POPPET

Fig. 6.16 (c) Pushing in of plunger (pump at rest)

When the plunger is pushed in with the pump at rest, the oil does not flow to the cylinder port B or the pressure at area P does not rise.

Also, the poppet does not move so that the oil at the cylinder port A does not return to the tank.

The cylinders thus remains unmoved.

PORT A

PLUNGER

POPPET

Fig. 6.17

- 92 -

PORT B

6. HYDRAULIC SYSTEM

6.1.4 VALVE CONTROLS The control valve plungers are actuated with the levers as shown in Figure 6.18, with each lever mounted on a single shaft.

The shafts are supported by brackets which attached to the front guard. Movement of each lever is transmitted through a rod to the respective plungers.

TILT LEVER LIFT LEVER

A

ROD

CONTROL VALVE

Details of A

Fig. 6.18 Valve Controls

- 93 -

ATTACHMENT LEVERS (OPTION)

6. HYDRAULIC SYSTEM

6.1.5 LIFT CYLINDER The lift cylinder is a single-acting piston type consisting of a cylinder, piston rod, piston and cylinder cap, and is installed in the outer mast frame.

The piston is secured to the piston rod with a snap ring, with a wear ring an packing on its outer diameter.

At the bottom of one cylinder is a cut-off valve which will act as a safety device if the high-pressure hose connecting the right and left cylinders bursts for any reason.

The cylinder cap has a bushing and an oil seal pressed to support the piston rod and provide dust proofness for the cylinder.

■ Cut-off valve operation When the oil returns from inside the cylinder to the oil tank, it passes through the holes A and B in the piston. If the flow rate of the oil is less than the control flow rate of the flow regulator valve, the pressure differential across the holes is smaller than the spring force, so that the piston won't move.

However, if the oil flow rate becomes greater than the control flow rate of the flow regulator valve for any reason such as a broken hose, the pressure differential becomes greater than the spring force and thus the piston moves to the left. This closes the hole A in the piston while only a small amount of oil flows out through the hole B so that the forks drops slowly.

Fig. 6.19 Flow Rate Smaller than Setting

Fig. 6.20 Flow Rate Greater than Setting

- 94 -

6. HYDRAULIC SYSTEM

① ② ③ ④ ⑤ 21

⑥

Cylinder support

⑳

⑦

⑧

⑨

⑲ ⑩

⑱

⑪

⑰

⑫

⑯

⑬ ⑭ ⑮

Fig. 6.21 Lift Cylinder (7 ton trucks)

- 95 -

1. PISTON HEAD 2. SHIM 3. WIPER SEAL 4. ROD PACKING 5. BUSHING 6. CYLINDER CAP 7. "O"-RING 8. CYLINDER 9. PISTON ROD 10. PISTON 11. LOCK RING 12. WEAR RING 13. PACKING 14. SPRING 15. CUT VALVE 16. LOCK NUT 17. ADJUSTMENT NUT 18. ANCHOR PIN 19. CHAIN 20. SHEAVE 21. SNAP RING

6. HYDRAULIC SYSTEM

① ② ③ ④

21

⑤

Cylinder support

⑳

⑥ ⑦ ⑧

⑨ ⑲ ⑱

⑩

⑰

⑪

⑯

⑫ ⑬

⑭ ⑮

Fig. 6.22 Lift Cylinder (8 ton trucks)

- 96 -

1. PISTON HEAD 2. SHIM 3. WIPER SEAL 4. ROD PACKING 5. BUSHING 6. CYLINDER CAP 7. "O"-RING 8. CYLINDER 9. PISTON ROD 10. PISTON 11. LOCK RING 12. WEAR RING 13. PACKING 14. CUT VALVE 15. SPRING 16. LOCK NUT 17. ADJUSTMENT NUT 18. ANCHOR PIN 19. CHAIN 20. SHEAVE 21. SNAP RING

6. HYDRAULIC SYSTEM

① ② 21

③

⑳

④

Cylinder support

⑤ ⑥ ⑲ ⑦ ⑧ ⑨

⑱ ⑰ ⑯

⑩ ⑪ ⑫ ⑬ ⑭ ⑮

Fig. 6.23 Lift Cylinder (10 ton trucks)

- 97 -

1. PISTON HEAD 2. SHIM 3. WIPER SEAL 4. ROD PACKING 5. BUSHING 6. CYLINDER CAP 7. "O"-RING 8. CYLINDER 9. PISTON ROD 10. PISTON 11. LOCK RING 12. WEAR RING 13. PACKING 14. CUT VALVE 15. SPRING 16. LOCK NUT 17. ADJUSTMENT NUT 18. ANCHOR PIN 19. CHAIN 20. SHEAVE 21. SNAP RING

6. HYDRAULIC SYSTEM

6.1.6 FLOW REGULATOR VALVE The flow regulator valve controls fork descending speed and acts as a safety device if the high-pressure hose bursts for any reason. It is located as shown in Figure 6.24.

LIFT CYLINDER (RIGHT)

LIFT CYLINDER

(LEFT) ■ Flow regulator valve operation The oil returning from the lift cylinders enters the from CONTROL chamber F , passing through chambers E , D , C , B VALVE and A , back to the control valve.

The more the oil flows through the hole C in the FLOW piston ⑤ , the greater the pressure differential across REGULATOR VALVE the piston ⑤ becomes to move the piston ⑤ to the right.

For this reason, the hole D is narrowed by the hole C so that the oil flow is restricted to slow the fork descending speed.

Fig. 6.24 When the forks are raised, the high-pressure oil from the control valve flows, passing through A , B , C , D , E and F , into the lift cylinders.

F

E

D C B

to OIL TANK

A

FREE FLOW CONTROLLED FLOW CONTROL VALVE SIDE

LIFT CYLINDER SIDE

①

②

③

④

⑤

⑥

⑦

1. SPRING 2. CASE 3. SPRING 4. BALL 5. PISTON

⑧

⑨

⑩

6. SLEEVE 7. ORIFICE 8. SPRING 9. "O"-RING 10. NIPPLE

Fig. 6.25 Flow Regulator Valve

- 98 -

6. HYDRAULIC SYSTEM

6.1.7 TILT CYLINDER The tilt cylinder is a double-acting type, and its piston rod end is supported by the mast and the cylinder tail is connected to the frame with a pin. This truck is provided with two tilt cylinders on both sides of the truck.

The tilt cylinder assembly consists primarily of a cylinder body, cylinder cap, piston and piston rod.

The piston, welded to the piston rod, has two packings and one wear ring on the circumference and moves along the inner surface of the cylinder by the force of hydraulic oil. A bushing is press-fitted inside the cylinder cap to support the piston rod, with a packing and a dust seal to provide oil tightness for the piston rod and the cylinder cap. The cap, fitted with an "O"-ring on the outer periphery, is screwed into the cylinder body and fastened with a lock ring.

When the tilt lever in the operator's room is tilted forward, high-pressure oil enters the cylinder tail side, moving the piston forward. This causes the mast to tilt forward 6 degrees. When the tilt lever is tilted backward, high-pressure oil enters the cylinder cap side and moves the piston backward, tilting the mast 12 degrees backward.

①

②

1. JOINT 2. SPACER 3. DUST SEAL 4. CYLINDER CAP

③ ④ ⑤

⑥

⑦

⑧

⑨ ⑩ ⑪ ⑫

5. OIL SEAL 6. "O"-RING 7. BUSHING 8. PISTON ROD

Fig. 6.26 Tilt Cylinder

- 99 -

9. CYLINDER 10. PACKING 11. WEAR RING 12. PACKING

6. HYDRAULIC SYSTEM

6.1.8 OIL TANK The oil tank is integral with the truck frame and located on the right side of the truck. Its construction is as shown in Figure 6.27.

The oil tank has two suction filter inside to remove dust and dirt from the oil.

from BRAKE CIRCUIT BREATHER CAP (W/LEVEL GAUGE)

from STEERING CIRCUIT

to REAR PUMP to FRONT PUMP

10 ton: 70 L (19.8 U.S. gal) 7 ton, 8 ton: 60 L (15.85 U.S. gal)

from CONTROL VALVE SUCTION FILTER (FRONT PUMP)

SUCTION FILTER (REAR PUMP)

Fig. 6.27 Hydraulic Piping Diagram

- 100 -

STEERING GEAR

TILT CYLINDER (LEFT)

CONTROL VALVE

ACCUMULATOR

BRAKE VALVE

STEERING CYLINDER

Fig. 6.28 Hydraulic Piping Diagram

- 101 -

REAR PUMP

FRONT PUMP

RETURN FILTER

TILT CYLINDER (RIGHT)

6. HYDRAULIC SYSTEM

6. HYDRAULIC SYSTEM

6.1.9 DISASSEMBLING AND REASSEMBLING CONTROL VALVE (1) Disassembly

Fig. 6.29 (a) Loosen the plug ⑦ by two or three turns and remove the connector ⑥ from the housing ① .

Note: Do not remove the plug ⑦ at this stage. The spool ② may drop on the land of the housing ① at the moment the connector leaves off the housing ① , so that the land may be damaged by the spring ③. (b) Remove the plug ⑦ from the housing ① . (c) Holding the sleeve ④ , install a bolt into the threaded area of the end of the spool ② and remove the sleeve ④ . (d) Remove the spool ② slowly. Care should be exercised so as not to allow it to drop on the land of the housing ① . (e) The ring ③ comes out along with the spool ② . (f) Remove the connector (6-1) and plug (6-3) from the connector ⑥ along with the ball (6-2). (g) Do not remove the snap ring ⑤ from the sleeve ④ ; otherwise it may get deformed. (h) Remove the "O"-rings from the plugs ( ⑦ , 6-3) and connector (6-1).

- 102 -

6. HYDRAULIC SYSTEM

(2) Reassembly After disassembly, clean all parts in clean mineral oil. Inspect each part for burrs, scratches or other defects. Due attention should be paid to the sliding area of the housing ① and diameter of the spool ② .

All "O"-rings should be replaced with new ones.

Fig. 6.30 (a) Apply a good quality grease in new "O"-rings and install them on the respective positions. (b) Install the sleeve ④ with the snap ring ⑤ on the housing ① . (c) Install a bolt into the threaded area in the spool ② and attach the spring ③ . Install the spool ② and spring ③ into the housing ① carefully. (d) Push in the spool ② slightly, and the sleeve ④ will project at the opposite side of the housing ① .

Holding both ends of the spool ② and sleeve ④ with your fingers, check to see if the spool ② moves smoothly. (e) Screw in the plug ⑦ by two or three turns so as not to allow the spool ② to drop on the land of the housing ① and install the connector ⑥ from the opposite side. (The connector ⑥ should be reassembled in the sequence opposite to disassembly.) (f) Tighten the plugs ( ⑦ , 6-3) and connector (6-1) to the specified torque.

- 103 -

6. HYDRAULIC SYSTEM

(3) Disassembly of relief valve (a) Loosen the plug ⑪ and remove it from the housing ① .

Note: If the lock nut is loosened, be sure to check the relief pressure with a pressure gauge thereafter. (b) Hold the convex part of the housing ⑪ in round pliers and remove the housing ⑪ from housing ① . (c) The poppet ⑩ comes out along with the housing ⑪ . (d) Put the housing ⑪ vertical and remove the spring ⑨ .

(4) Reassembly Clean all parts and make sure to get all necessary parts. Visually check the seats of the housing ⑪ and poppet ⑩ for any sign of defect. Reassembly should be performed in a sequence opposite to disassembly.

(5) Adjustment of relief valve ■ Main relief valve (a) Remove the plug from the outlet section gauge port (PT1/4) and install a pressure gauge on the port. (b) Loosen the lock nut of the relief valve and turn loose the adjuster by 1/4 or 1/2 of a turn. (c) Start the engine. Move the tilt cylinder to the stroke end and read the pressure gauge. (d) When the reading is not as specified, obtain the specified value by turning the adjuster. (e) Tighten the lock nut and recheck the pressure. (f) Remove the pressure gauge. Install the plug on the gauge port.

Main relief pressure: 19.6 MPa {200 kg/cm2 (2845 psi)} ■ PF relief valve (a) Remove the plug from the outlet section PF gauge port (PT1/8) and install a pressure gauge on the port. (b) Loosen the lock nut of the PF relief valve and turn loose the adjuster by 1/4 or 1/2 of a turn. (c) Start the engine. Move the tilt cylinder to the stroke end and read the pressure gauge. (d) When the reading is not as specified, obtain the specified value by turning the adjuster. (e) Tighten the lock nut and recheck the pressure. (f) Remove the pressure gauge. Install the plug on the gauge port.

PF relief pressure: 11.8 MPa {120 kg/cm2 (1707 psi)}

- 104 -

7. LOAD HANDLING SYSTEM

7. LOAD HANDLING SYSTEM 7 ton

Name

8 ton

10 ton

VM-30C VM-30F VM-30G

Type Roller type 2-stage telescopic mast with free lift Standard max. lifting height

3000 mm (118.11 in)

Fork lifting system

Hydraulic

Fork tilting system

Hydraulic

Lift chain

Leaf chain BL1034

Leaf chain BL1046

Leaf chain BL1434

Mast rail dimensions Cross section of outer rail

A: 152+1.5 mm A: 184+1.5 mm 0 0

(6.0+0.06 in) (7.24+0.06

-0 -0 in)

B: 30 ± 0.8 mm B: 30 ± 0.8 mm (1.18 ± 0.03 in) (1.18 ± 0.03 in)

C: 212 mm C: 244 mm (8.35 in) (9.61 in)

D: 67 ± 0.6 mm D: 67 ± 0.6 mm (2.64 ± 0.02 in) (2.64 ± 0.02 in)

E: 67 ± 0.6 mm E: 67 ± 0.6 mm (2.64 ± 0.02 in) (2.64 ± 0.02 in)

Cross section of inner rail

A: 152+1.50 mm A: 184+1.5

0 mm

(6.0+0.06 in) (7.24+0.06

-0 -0 in)

B: 30 ± 0.8 mm B: 30 ± 0.8 mm (1.18 ± 0.03 in) (1.18 ± 0.03 in)

C: 212 mm C: 244 mm (8.35 in) (9.61 in)

D: 67 ± 0.6 mm D: 67 ± 0.6 mm (2.64 ± 0.02 in) (2.64 ± 0.02 in)

E: 115 ± 1 mm E: 115 ± 1 mm (4.53 ± 0.04 in) (4.53 ± 0.04 in)

- 105 -

←

7. LOAD HANDLING SYSTEM

7.1 GENERAL DESCRIPTION

The load handling system is of roller type having a two-staged telescopic mast. It consists of an outer channel, inner channel and carriage.

7.1.1 OUTER & INNER CHANNEL Outer and inner channels are of welded construction. The lower part of the outer channel is provided with a support to be used for installing the mast assembly on the drive axle.

The center of the outer channel is supported by the frame via the tilt cylinder. The mast assembly tilts forward and rearward by expanding and contracting the tilt cylinder.

The outer channel has a ]-shaped section (J-shaped section for VM-30G) and is provided with end rollers and side rollers at their upper parts.

The inner channel has a J-shaped section and is provided with end rollers and side rollers at their lower parts. ⑥ ⑤ ④

⑦

⑧

③

⑨

⑩

② ① ⑪

⑫ ⑬ ⑭

Fig. 7.1 Outer and Inner Channel (VM-30C)

- 106 -

1. INNER CHANNEL 2. OUTER CHANNEL 3. CHAIN SHEAVE 4. SLIPPER 5. SHIM 6. SPACER 7. SHIM 8. SIDE ROLLER 9. BUSHING 10. CAP 11. END ROLLER 12. SPACER 13. SHIM 14. SIDE ROLLER

7. LOAD HANDLING SYSTEM

⑥

⑤

⑦

④

1. INNER CHANNEL 2. OUTER CHANNEL 3. CHAIN SHEAVE 4. SLIPPER 5. SHIM 6. SPACER 7. SHIM 8. SIDE ROLLER 9. BUSHING 10. CAP 11. END ROLLER 12. SPACER 13. SHIM 14. SIDE ROLLER

⑧

③

⑨ ② ① ⑪

⑫

⑬ ⑭

Fig. 7.2 Outer and Inner Channel (VM-30F)

- 107 -

⑩

7. LOAD HANDLING SYSTEM

⑥ ⑤

⑦

1. INNER CHANNEL 2. OUTER CHANNEL 3. CHAIN SHEAVE 4. SLIPPER 5. SHIM 6. SPACER 7. SHIM 8. SIDE ROLLER 9. BUSHING 10. CAP 11. END ROLLER 12. SPACER 13. SHIM 14. SIDE ROLLER

⑧

④

③

② ⑨

① ⑪

⑫

⑬ ⑭

Fig. 7.3 Outer and Inner Channel (VM-30G)

- 108 -

⑩

7. LOAD HANDLING SYSTEM

7.1.2 CARRIAGE The carriage has end rollers that roll along the inside of the inner channels, each installed on the end roller shaft through a bearing with a snap ring. The end roller shafts are welded to the carriage. The side rollers that roll along on the inside collar of each inner channel are bolt fitted, being shim adjusted.

The carriage has also retaining rollers, each installed on its right and left sides, absorb the side thrust of the finger bar and roll along on the outside of the inner channel.

Longitudinal load is received by the end rollers, and lateral load by the upper-located retaining rollers and lower-located side rollers.

⑦ 1. FORK 2. STOPPER 3. SPRING 4. WHEEL 5. RETAINING ROLLER 6. SNAP RING 7. BACK REST 8. SHIM 9. SHAFT 10. SIDE ROLLER 11. SNAP RING 12. SNAP RING 13. END ROLLER 14. CARRIAGE

④ ③ ②

⑤

⑥

⑧ ⑨

⑪ ⑩

⑬ ⑫

⑭

①

Fig. 7.4 Carriage (VM-30C)

- 109 -

7. LOAD HANDLING SYSTEM

⑦

④ ⑤

⑥ ⑧

③ ②

⑨

⑪ ⑩

⑬ ⑫

⑭

①

Fig. 7.5 Carriage (VM-30F)

- 110 -

1. FORK 2. STOPPER 3. SPRING 4. WHEEL 5. RETAINING ROLLER 6. SNAP RING 7. BACK REST 8. SHIM 9. SHAFT 10. SIDE ROLLER 11. SNAP RING 12. SNAP RING 13. END ROLLER 14. CARRIAGE

7. LOAD HANDLING SYSTEM

②

④ ⑤

③

⑦

⑥

⑧

①

⑨

⑩

⑪

⑫

Fig. 7.6 Carriage (VM-30G)

- 111 -

1. FORK 2. SNAP RING 3. END ROLLER 4. SHIM 5. SIDE ROLLER SHAFT 6. SIDE ROLLER 7. SNAP RING 8. RETAINING ROLLER 9. SNAP RING 10. CARRIAGE 11. SHAFT 12. STOPPER

7. LOAD HANDLING SYSTEM

7.1.3 LOCATIONS OF ROLLERS The end, side and retaining rollers are installed on the outer channel, inner channel and carriage respectively. The end rollers support longitudinal load and the side rollers support lateral load so that the inner channels and carriage are raised and lowered smoothly.

Lower section

Upper section

CARRIAGE

RETAINING ROLLER END ROLLER SIDE ROLLER (adjust with shims)

SIDE ROLLER (adjust with shims) END ROLLER

SLIPPER (adjust with shims) OUTER CHANNEL INNER CHANNEL

Fig. 7.7 Location of Rollers (VM-30C)

- 112 -

7. LOAD HANDLING SYSTEM

VM-30F Lower section

Upper section CARRIAGE

SIDE ROLLER (adjust with shims) END ROLLER

RETAINING ROLLER END ROLLER SIDE ROLLER (adjust with shims) INNER CHANNEL SLIPPER (adjust with shims)

OUTER CHANNEL

VM-30G Lower section

Upper section CARRIAGE

END ROLLER OUTER CHANNEL

SIDE ROLLER (adjust with shims) END ROLLER

SIDE ROLLER (adjust with shims) INNER CHANNEL SLIPPER (adjust with shims)

Fig. 7.8 Locations of Rollers (VM-30F, VM-30G)

- 113 -

RETAINING ROLLER

7. LOAD HANDLING SYSTEM

7.2 MAINTENANCE

7.2.1 ADJUSTING LIFT CYLINDER ROD WITH SHIM After the lift cylinder, inner channel, and outer channel are replaced, the lift cylinder rod length needs to be adjusted.

(1) Install the piston head on each rod of the right and left cylinders without shim.

PISTON HEAD SHIM (2) Extend the lift cylinder rod slowly and check the difference of the time till each of right and left cylinder rods reaches the stroke end.

CYLINDER ROD (3) Add shim between the rod and piston head which CYLINDER CAP stop first.

Shim thickness: 0.2 to 0.5 mm (0.0079 to 0.0197 in) (4) Adjust the lift chain tension.

LIFT CYLINDER

Fig. 7.9

7.2.2 ADJUSTING HEIGHT OF CARRIAGE (1) Stop the truck on a level surface and stand the mast vertically.

(2) Keep the fork bottom on the ground and adjust the projected amount of carriage lower end roller to the value as shown in Table 7.1, using the chain anchor pin at the mast side.

Table 7.1

TIRE

INNER CHANNEL CARRIAGE END ROLLER FORK

Model

Mast Type

7 ton

VM-30C

50 - 55 (1.97 - 2.17)

8 ton

VM-30F

31 - 36 (1.22 - 1.42)

10 ton

VM-30G

31 - 36 (1.22 - 1.42)

mm (in)

- 114 -

Fig. 7.10

7. LOAD HANDLING SYSTEM

(3) Make sure that the clearance between the carriage and the inner channel stoppers is the value shown in the Table 7.2, when the fork is raised to the maximum lifting height.

INNER CHANNEL STOPPER

Note 1: When the mast lifting height is over 4000 is + 50 mm (1.97 in). mm, the dimension Note 2: If the mast has no free mast mechanism and the dimension becomes zero, the lift cylinder force presses against the carriage stopper. This causes the damage of the stopper and the carriage will pop out.

CARRIAGE STOPPER

CHAIN ANCHOR PIN AT MAST SIDE

Fig. 7.11 Table 7.2 Model

Mast Type

Free Lift Mechanism

mm (in)

7 ton

VM-30C

None

15 - 20 (0.591 - 0.787)

8 ton

VM-30F

None

15 - 20 (0.591 - 0.787)

10 ton

VM-30G

None

15 - 20 (0.591 - 0.787)

(4) Adjust the tension of the right and left chains to the same value with the chain anchor pin at the mast side when the fork is at the bottom position and the mast is tilted back all the way.

CHAIN

ANCHOR PIN

ADJUSTMENT NUT

LOCK NUT

Fig. 7.12

- 115 -

7. LOAD HANDLING SYSTEM

7.2.3 PROCEDURE FOR REPLACING ROLLERS AT CARRIAGE SIDE (1) Attach the pallet to the fork and stop the truck on a level surface.

(2) Lower the fork with the pallet to the ground.

(3) Remove the joint link of the mast side anchor pin and remove the chain from the sheave.

(4) Extend the lift cylinder rod to raise the inner channel. (See ① in Figure 7.13) (5) Move the truck backwards after making sure that the carriage is removed from the inner channel.

(See ② in Figure 7.13) (6) Replacing end rollers ① Remove the snap ring from each end roller and remove all end rollers with a puller. ② Install new end rollers and secure them with snap rings. Check for the stamp of L and install the roller which is marked the same stamp, pointing the stamp side to the carriage side.

Fig. 7.13

Stamp (L or none)

Fig. 7.14 (7) Replacing side rollers ① Remove the side roller assembly. Keep the numbers of the shims and their combination as they were. ② Remove the snap ring and pull out the roller from the shaft. ③ Install a new roller onto the shaft and secure it with the snap ring. ④ Install the side roller assembly using the shims removed in step ① . ⑤ If there is excessive looseness between the side roller and inner channel, add the shims between the end roller and the side roller.

- 116 -

SNAP RING

Fig. 7.15

7. LOAD HANDLING SYSTEM

(8) Extend the lift cylinder rod so that the inner channel bottom projects the upper section of the carriage.

(9) Bring the truck close to the carriage side so that each roller enters inside of the outer channel.

(See ① in Figure 7.16) (10) Contact the lift cylinder rod to lower the inner channels gradually. Place each roller of the carriage into the inner channel.

(11) Engage the chain with the sheave and connect the chain and anchor through the joint link.

(12) Adjust the height of the carriage. (See 7.2.2.)

- 117 -

Fig. 7.16

7. LOAD HANDLING SYSTEM

7.2.4 PROCEDURE FOR REPLACING ROLLERS AT MAST SIDE (1) Remove the carriage from the inner channel in the same procedure as described in "7.2.3 PROCEDURE FOR REPLACING ROLLERS AT CARRIAGE SIDE." (2) Move the truck to a level surface and put the both front wheels on the bench of 250 - 300 mm (9.8 11.8 in) in height.

(3) Apply the parking brake and block the both rear wheels securely with blocks.

(4) Remove the bolt securing the lift cylinder and inner channel, and hoist the inner channel with a crane, keeping shims at the end of the piston rod.

(5) Remove the lift cylinder mounting bolt at the lower section of the outer channel and cylinder support at the middle section, and remove the lift cylinder from the outer channel. Remove the hydraulic hose with two wrenches, using caution not to loosen the fittings at the cylinder side.

(6) Operate the crane to lower the inner channel gradually and remove the end roller from the lower section of the inner channel. At the same time, the end at upper section of the outer channel can also be removed.

(7) Replacing end rollers ① Remove the snap ring from the upper end roller shaft. ② Remove the upper end roller with a puller. ③ Install a new end roller and secure it with a snap ring. Check for the stamp of L and install the roller which is marked the same stamp, pointing the stamp side to the carriage side. (See Figure 7.14) ④ Replace the lower end roller, using same procedure as above. In this step, point the stamp side to the outer side.

Fig. 7.17

SHIM

SPACER SHIM SIDE ROLLER

SLIPPER

END ROLLER

END ROLLER

SPACER SHIM SIDE ROLLER

Fig. 7.18

- 118 -

7. LOAD HANDLING SYSTEM

(8) Replacing side rollers SNAP RING ① Remove the upper side roller assembly from the outer channel. Keep the numbers of the shims and their combination as they were. ② Remove the snap ring and pull out the roller from the shaft. ③ Install a new roller onto the shaft and secure it with the snap ring. ④ Install the roller assembly with the shims removed in step 1.

Fig. 7.19 ⑤ If there is excessive looseness between the inner and outer channels, add the shims to the side roller.

(9) Operate the crane to hoist the inner channel. Place each roller into the channels.

(10) Install the lift cylinder and carriage in the reverse order of disassembly.

- 119 -

7. LOAD HANDLING SYSTEM

NOTE

- 120 -

8. STEERING SYSTEM (ORBITROL TYPE)

8. STEERING SYSTEM (ORBITROL TYPE) Steering axle: Type:

King pin angle: Toe-in: Camber: Caster: Steering angle:

Inner wheel:

Outer wheel: Orbitrol:

Type:

Discharge: Power cylinder:

Type:

Cylinder bore:

Piston rod diameter:

Stroke: Valve unit: (Include control valve)

Flow rate:

Pressure setting:

Center-pin supported, Elliot type with box-shaped cross section of weld construction 0˚ 0 mm 1˚ 0˚ 76˚ 50˚ Open center, non-load reaction type 277 cm3 (16.88 in3)/rev.

Double-acting piston type 115 mm (4.53 in) 85 mm (3.35 in) 216 mm (8.5 in) (7.8 ton), 260 mm (10.21 in) (10 ton) 27 L/min (7.1 U.S. gal/min) 11.8 MPa {120 kgf/cm2 (1706 psi)}

8.1 GENERAL DESCRIPTION

The steering system consists primarily of a steering wheel, orbitrol, and power cylinder. When the steering wheel is turned, the rotation is transmitted to the orbitrol. The oil passages in the orbitrol are changed over to direct the hydraulic pressure from the valve unit to the power cylinder which extends or contracts depending on the hydraulic pressure, thereby steering the truck.

- 121 -

8. STEERING SYSTEM (ORBITROL TYPE)

8.1.1 STEERING AXLE The steering axle is of steel-welded construction with a box shaped cross section, incorporating a power cylinder inside it. See Figure 8.1. The power cylinder is housed in the axle to protect it from being damaged by obstacles on the road surface. The axle is installed onto the truck frame through a center pin with bushing and cap, and it cradles around this center pin.

Tightening torque: 470.7 - 549.2 N·m

{4800 - 5600 kgf-cm

(347 - 405 ft-lbs)} Tightening torque: 232.4 - 294.2 N·m

{2370 - 3000 kgf-cm

(171 - 217 ft-lbs)}

① ②③④

⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫

Tightening torque: 245.2 - 294.2 N·m

{2500 - 3000 kgf-cm

(181 - 217 ft-lbs)} Tightening torque: 470.7 - 549.2 N·m

{4800 - 5600 kgf-cm

(347 - 405 ft-lbs)} (Apply LOCTITE#270)

⑱

1. PS CYLINDER 2. SPHERICAL BUSHING 3. pin 4. Joint 5. NEEDLE BEARING 6. Thrust bearing

⑰

⑯ ⑮ ⑭ ⑬

7. Hub 8. Taper roller bearing 9. LOCK NUT (INNER) 10. LOCK NUT (OUTER) 11. Taper roller bearing 12. Oil seal

Fig. 8.1 Steering Axle

- 122 -

13.

14.

15.

16.

17.

18.

Knuckle King pin Oil seal Spacer NEEDLE BEARING LOCK PIN

8. STEERING SYSTEM (ORBITROL TYPE)

(1) Knuckle and king pin The king pin is secured to the knuckle with a lock pin at its flank and to the bosses of the axle assembly with needle bearings at its top and bottom.

Between the upper boss and the knuckle is a thrust bearing to let the knuckle rotate around the king pin smoothly under a heavy load.

The needle and thrust bearings are lubricated with grease supplied through the grease fittings at the top and bottom of the king pin.

CAP GASKET King pin

NEEDLE BEARING

COLLAR

OIL SEAL

THRUST BEARING

NEEDLE BEARING

Knuckle

SPACER NEEDLE BEARING OIL SEAL

LOCK PIN

SHIM

Fig. 8.2 Knuckle

(2) Wheel hub The wheel hub is fitted to the spindle of the knuckle with two tapered roller bearings and preloaded with a nut.

- 123 -

8. STEERING SYSTEM (ORBITROL TYPE)

8.1.2 STEERING WHEEL ASSEMBLY The steering wheel assembly is arranged as shown in Figure 8.3. The orbitrol is located at the bottom of the assembly. At the center of the wheel is the horn button.

The steering shaft is connected to the drive shaft of the orbitrol and the steering wheel can be moved to a certain extent back and forth to suit the operator's physique.

Steering wheel

Lock lever

Orbitrol

Fig. 8.3 Steering Wheel Assembly

- 124 -

8. STEERING SYSTEM (ORBITROL TYPE)

8.1.3 ORBITROL The orbitrol sends pressure oil from the pump selectively to the power cylinder. It consists primarily of a control valve and a metering device. Figure 8.4 shows the cross sectional views of the orbitrol.

The control valve used in the orbitrol is not an ordinary spool valve whose spool moves in the axial direction, but a rotary valve which consists of a sleeve and a spool that rotate together forming different oil passages through the combination of their oil holes. The valve housing is provided with four ports which lead to the pump, tank, right and left chambers of the cylinder. Between the inlet port and return port is a check valve.

The metering device consists of an internally toothed stator and an externally toothed rotor. During normal operation, it operates as an oil motor. In an emergency, it can be used as hand pump. The rotor is mechanically linked with the sleeve through the drive shaft so that feedback operation is possible.

The sleeve is interlocked with the motor's rotor through the cross pin and drive shaft while the spool is splined to the steering shaft.

Sleeve

Check valve

Spool

Plug

Trochoid motor

Thrust bearing

Drive shaft Sleeve Spool

Leaf spring

Drive shaft

Fig. 8.4 Orbitrol

- 125 -

Pin

8. STEERING SYSTEM (ORBITROL TYPE)

(1) Operation of orbitrol (a) In "Neutral" While the steering wheel is in straight position, the oil from the pump flows through oil passage ① to oil groove ② . The sleeve has 24 oil holes ③ which are now in line with the holes ④ in the spool so that the oil that flowed into groove ② passes through oil holes ③ and ④ to space ⑤ between the spool and drive shaft. Then the oil flows through spool groove ⑥ and sleeve groove ⑦ back to the oil tank.

Since cylinder ports ⑳ and 21 are respectively open to oil holes ⑱ and ⑰ in the sleeve but not to groove ⑯ nor ⑲ in the spool, the oil in the cylinder does not go any where.

Oil passage ⑮ that leads to the hydraulic motor is open to oil hole ⑭ in the sleeve which is used as the inlet and outlet for the hydraulic motor, but not to grooves ⑬ nor ⑯ in the spool and thus the oil remain unmoved.

Fig. 8.5 (b) When steering wheel is turned counterclockwise As the steering wheel is turned counterclockwise, the grooves in the spool shift to the left in relation with the holes and grooves in the sleeve so that holes ④ in the spool get out of line with holes ③ in the sleeve. The oil that has flowed into groove ② thus far begins to flow into hole ⑫ in the sleeve, passing through grooves 23 and ⑬ in the spool, hole ⑭ in the sleeve, and oil passage ⑮ in the housing, to the hydraulic motor.

The hydraulic motor thus rotates in the counterclockwise direction and the oil discharged from the hydraulic motor flows through oil hole ⑭ in the sleeve, groove ⑯ in the spool, and oil hole ⑱ in the sleeve to the cylinder port L and thus actuates the steering cylinder.

The returning oil from the power cylinder flows, passing through the cylinder port R, groove ⑪ in the valve housing, oil hole ⑰ in the sleeve, groove ⑲ in the spool, oil hole 22 in the sleeve, and groove ⑧ in the valve housing, back to the oil tank.

Fig. 8.6

- 126 -

8. STEERING SYSTEM (ORBITROL TYPE)

(c) When steering wheel is turned clockwise As the steering wheel is turned clockwise, the grooves in the spool shaft to the right in relation to the oil holes and grooves in the sleeve so that oil holes ④ in the spool get out of line with holes ③ in the sleeve. The oil that has flowed into groove ② thus far begins to flow into oil hole ⑫ in the sleeve and then flows through grooves 23 and ⑬ in the spool, oil hole ⑭ in the sleeve, and oil passage ⑮ in the valve housing to the hydraulic motor. The hydraulic motor thus rotates in the clockwise direction and the oil discharged from the hydraulic motor flows through oil hole ⑭ in the sleeve, groove ⑯ in the spool, and oil hole ⑰ in the sleeve to the cylinder port R in the housing and thus actuates the power cylinder.

The returning oil from the power cylinder flows, passing through the cylinder port L, groove ⑩ in the housing, oil hole ⑱ in the sleeve, groove ⑲ in the spool, oil hole 22 in the sleeve and groove ⑨ in the housing back to the oil tank.

Fig. 8.7 (2) Relationship between rotating speed and operating force of steering wheel In principle, the force required to operate the orbitrol is only the force to change over the valve, i.e. the force of compressing the centering the centering spring or 2.94 N·m {0.3 kg–m (2.17 ft-lbs)}. In other words, since there are no mechanical connections between the steering wheel and the tires and only the spring compressing force is required, constant steering force is kept even at increased rotational speed.

The discharge of oil supplied from the rotor of the orbitrol to the cylinder is 277 cm3 (16.88 in3)/revolution.

(3) Neutral feedback of orbitrol The neutral feedback of the orbitrol is performed by changing-over in oil passages of the valve, due to the reactions force of centering spring. (When the steering wheel is turned and then released with the pump at rest, the steering wheel returns to the initial position.) Unless the neutral feedback is completely performed, the steering wheel may be turned, even though the operator does not turn the steering wheel.

(4) Steering with defective pump When the pump fails to supply hydraulic oil the orbitrol serves as an emergency hand steering device.

When the steering wheel is turned, the spool rotates. When turned by about 8˚, the spool contacts the cross pin, which rotates the drive shaft, which in turn rotates the rotates the rotor. Thus the metering device serves as a hand pump to supply oil to the cylinder. In this case the check valve provided between the return port and the suction port opens, so that oil flows from the cylinder to the suction side, thereby effecting an emergency steering.

- 127 -

8. STEERING SYSTEM (ORBITROL TYPE)

8.1.4 POWER CYLINDER The power cylinder is installed in the steering axle and is operated by oil from the orbitrol. The cylinder body is secured to the axle, with both rod ends connected to the knuckle with joints.

The cylinder cap has a bushing, oil seal, and dust seal, being secured to the cylinder with a lock washer.

①

1. WIPER SEAL 2. PACKING 3. BUSHING

② ③

④

⑤

⑥

4. "O"-rING 5. PACKING 6. CYLINDER

Fig. 8.8 Power Cylinder

- 128 -

⑦

⑧

7. CYLINDER CAP 8. ROD

8. STEERING SYSTEM (ORBITROL TYPE)

8.2 PREVENTIVE MAINTENANCE

8.2.1 DISASSEMBLY AND MAINTENANCE OF ORBITROL Prior to attempting to disassemble the orbitrol, clean the exterior of the unit and select a clean working place.

(1) Lightly hold the flange of the orbitrol in a vise equipped with a soft jaws (copper or other inserts) with the end cap upward. Do not hold it strongly.

Fig. 8.9 (2) Remove the fitting bolts from the end cap and remove the end cap.

Note: One of the seven bolts has a different shape from the others. Mark the housing to insure correct reassembly.

End cap

"O"-ring

Remove the "O"-ring from the end cap.

Fig. 8.10 (3) Remove the spacer from the spline section of the rotor set and remove the rotor set.

Note: Use caution not to lose the rotor set star.

Remove the "O"-ring from the rotor set.

Rotor set "O"-ring

Spacer

Fig. 8.11

- 129 -

8. STEERING SYSTEM (ORBITROL TYPE)

(4) Remove the spacer plate, "O"-ring, and drive from the housing.

Spacer plate "O"-ring

Drive

Fig. 8.12 (5) Remove the adapter screw from the housing.

Remove the ball.

Adapter screw Ball

Fig. 8.13 (6) Remove the housing from the vise and put it on clean cloth with the machined surfaced down.

Remove the retaining ring from the housing by first prying its end off with a small screwdriver.

CAUTION Wear protective glasses to protect your eyes from the retaining ring which might pops out of the housing.

(7) Turn the spool and sleeve so that the pin is parallel with the port surface. Then push the spool and sleeve in the housing, removing the seal gland bushing from the housing.

Fig. 8.14

Seal gland bushing

Fig. 8.15 (8) Remove the x-ring seal or one-piece teflon seal and dust seal from the seal gland bushing.

Note: The seal gland bushing has an x-ring or onepiece teflon seal incorporated. Use caution not to damage the seal gland seal when removing the seals.

X-ring seal Seal gland bushing

Dust seal

Fig. 8.16

- 130 -

8. STEERING SYSTEM (ORBITROL TYPE)

(9) Remove the thrust bearing.

Bearing race

Thrust bearing

Fig. 8.17 (10) Remove the spool and sleeve from the housing in the direction indicated by arrow in Figure 8.18.

Remove the pin from the spool and sleeve assembly.

Note: Mark the sleeve and spool with oil-based marker to insure correct reinstallation.

Fig. 8.18 (11) Remove the spool a part way from the sleeve and remove the centering spring from the spool.

CAUTION Wear protective glasses to protect your eyes from the centering spring which might pop out of the spool.

Fig. 8.19

- 131 -

8. STEERING SYSTEM (ORBITROL TYPE)

8.2.2 REASSEMBLY OF ORBITROL Inspect the contact surfaces of all parts for scores, scratches or burrs which would cause oil leak if neglected, and if unsatisfactory, replace with new ones. Clean all metallic parts and dry with compressed air. For drying purpose, do not use cloth or paper; otherwise lint or paper dust sticks on the surface and would cause trouble in the hydraulic equipment. Replace will "O"-rings and seals with new ones.

(1) Align the grooves in the spool with those in the sleeve and put the spool into the sleeve, turning the spool slowly.

Spring glove Control sleeve Spring glove

Control spool

Match mark

Fig. 8.20 (2) Align the spring groove in the spool with that in the sleeve and put them on a plane plate. Install the spring.

CAUTION Wear protective glasses to protect your eyes from the centering spring which might pop out of the spool.

Fig. 8.21

(3) Insert the pin through the spool and sleeve holes.

Pin

Fig. 8.22 (4) Install the spool and sleeve assembly in the housing from the rear side. Use caution not to allow the sleeve assembly end face to go farther inside from the housing shoulder surface.

Fig. 8.23

- 132 -

8. STEERING SYSTEM (ORBITROL TYPE)

(5) Install the thrust bearing and "O"-ring on the housing.

Thrust needle bearing

Bearing race

"O"-ring

Fig. 8.24 (6) Install the dust seal and X-ring seal on the seal gland bushing.

Retaining ring Seal gland bushing (w/ seal)

Fig. 8.25 (7) Insert the seal gland bushing into the spool, turning the latter slowly. Drive the bushing in place with a plastic hammer. Install the retaining ring on the housing.

CAUTION Wear protective glasses to protect your eyes from the retaining ring which might pop out of the housing.

Driver Dust seal Retaining ring Seal gland bushing X-ring seal "O"-ring

Fig. 8.26

Fig. 8.27 (8) Hold the housing in a vise. Make sure that the end faces of the spool and sleeve are sunk from the housing surface.

Fig. 8.28

- 133 -

8. STEERING SYSTEM (ORBITROL TYPE)

(9) Install the ball in the position shown in Figure 8.29 and attach the adapter screw.

Adapter screw Ball

Fig. 8.29 (10) Install the "O"-ring on the housing. Clean the surfaces of the housing and spacer plate, then put the spacer plate on the housing.

Fig. 8.30 (11) Turn the spool and sleeve assembly so that the port surface is parallel to the pin and install the drive.

Draw a line on the drive's spline end face, parallel to the pin.

Port surface

Parallel to port surface

Pin

Fig. 8.31 (12) Install the "O"-ring on the rotor set.

Fig. 8.32

- 134 -

Drive

8. STEERING SYSTEM (ORBITROL TYPE)

(13) Putting the "O"-ring side of the rotor set toward the spacer plate side, place the rotor on the housing, with the star's root aligned with the drive (see Figure 8.33). Then, securing the engagement of the drive and the star, align the bolt holes in the rotor set with those in the housing.

A B C

Fig. 8.33 (14) Install the spacer in the rotor set and install the "O"-ring on the end cap.

End cap "O"-ring

Spacer

Fig. 8.34 (15) Put the end cap on the rotor set and align the bolt holes with each other. Apply oil on the thread parts of the bolts and tighten them to the torque of 14.7 N·m {1.5 kgf-m (10.8 ft-lbs)}. Then tighten them to 22.6 N·m {2.3 kgf-m (16.6 ft-lbs)} torque in the order indicated in Figure 8.35.

Note: Remember that one of the seven bolts at the marking position of the housing has a different shape from the others.

- 135 -

6

4 2

1 3

5

7

Fig. 8.35

D

8. STEERING SYSTEM (ORBITROL TYPE)

8.2.3 ADJUSTING PRELOAD OF REAR WHEEL BEARING (1) As shown in Figure 8.36, apply grease to the hub, inner bearing, outer bearing, and cap. Also apply grease to the oil seal lips.

(2) Set the bearings on the hub, then install the hub on the knuckle spindle.

(3) Place a washer, then tighten the adjustment nut with a torque of 205.9 - 235.4 N·m {21 to 24 kgf-m (151.9 - 173.6 ft-lbs)}. Loosen the adjustment nut, then retighten it with a torque of 9.8 N·m {1 kgf-m (7.2 ft-lbs)}.

(4) Gently tapping the hub with a mallet, make sure there is no looseness.

(5) Tighten the adjustment nut to the position where the cotter pin can be set.

(6) Tapping the hub with a mallet, give it a few turns. Then measure the starting force.

Starting force: 107.9 - 156.9 N {11 - 16 kgf (24.3 - 35.3 lbs)} (7) If the starting force measured is beyond the standard range, replace the washer and adjustment nut.

Then, repeat the steps from (3) to (6) till the standard range is acquired.

(8) Lock the adjustment nut with cotter pin.

Outer bearing Inner bearing

Washer Cap

Cotter pin Adjustment nut Hub

Oil seal

Fig. 8.36 Pre-Load Adjustment

- 136 -

8. STEERING SYSTEM (ORBITROL TYPE)

8.2.4 TROUBLESHOOTING GUIDE Trouble

Steering wheel is hard to turn.

Truck is zigzagged or

swung.

Unusual

temperature

Oil leakage Steering wheel cannot be operated.

Problem Location Defective or damaged pump Stuck or damaged relief valve Stuck, damaged or worn relief control valve Damaged hose joint and clogged oil passage Low oil level in the oil tank Insufficient air bleeding Low pressure Stuck or damaged control valve Loose spool in the control valve Damaged control valve Broken or weakened spring Low oil level in the oil tank Clogged inlet tube or filter Stuck or broken control valve Improperly installed or damaged O-ring or oil seal of piping or control valve

- 137 -

Remedy Replace.

Wash or replace.

Replace or rub.

Replace or wash.

Add oil.

Bleed air.

See the preceding item.

Wash or replace.

Adjust tightening of the lock nut.

Replace.

Replace.

Add oil.

Wash or replace.

Replace.

Replace

View looking from A

ORBITROL

A

CONTROL VALVE

Fig. 8.37

- 138 BRAKE VALVE

ACCUMULATOR

POWER CYLINDER

RETURN FILTER

8. STEERING SYSTEM (ORBITROL TYPE)

9. ELECTRIC WIRING

9. ELECTRIC WIRING 9.1 ELECTRICAL SYSTEM

The electric components of the truck are wired through several types of wire harnesses and the color coded by circuit.

The wire harnesses are connected with connectors (2 types) or screw.

Example: Yellow coating with a blue marking

B

Black

G

Green W

White

L

Blue

Yellow

O

Orange

P

Pink

R

Y

Red

Lg Light green Sb

Light blue

Example: White coating without marking

Table 9.1 Color symbols and examples

Connecting type

Plug-in type

Plug-in side

Receptacle side

Remarks The alphabet letters mean colors.

(Table 9.1)

Housing Plug Screw type Table 9.2 Connector symbol

The dotted lines in the circuit diagrams are given for optional equipment.

DANGER! Use due caution when handling the battery unit.

1. Never short the circuit, spark, smoke or use fire near the battery unit. Since flammable gas is always released from the battery, there is a danger of causing an explosion.

2. The battery electrolyte is dilute sulfuric acid. It will cause burns if it gets on the skin. If electrolyte comes in contact with the skin, flash with water. It can cause blindness if it gets into eyes. If electrolyte gets into your eyes, flush your eyes out with water and get to a doctor.

- 139 -

9. ELECTRIC WIRING

9.1.1 INTERLOCK SYSTEM 1) TRAVEL AND LOAD HANDLING INTERLOCK

The traveling and load handling interlock system is a safety device for lift trucks.

When the operator gets out of the seat, the system turns on a switch that shifts the transmission into neutral and locks all the load handling levers. This system helps prevent an accident from happening if the operator of the truck is not in the driving position or a control is moved unintentionally when he is not in the operator’s seat.

Interlock operation A buzzer sounds if the operator leaves his seat while the starter switch is on. After about 3 seconds, the transmission is locked in neutral and the hydraulic circuit is blocked (i.e., the truck won’t move nor the load handling system won’t operate without an operator in the seat even if the shift lever or any load handling lever is operated). The warning light comes on.

(If the operator returns to the operator’s seat within 3 seconds, the buzzer stops and it is possible to start the truck and operate the load handling system as usual.)

The buzzer also sounds and the lifting operation is locked off if the operator leaves his seat without applying the parking brake when the starter switch is off.

Releasing interlocks • Releasing traveling interlock When the operator gets in the operator’s seat and shifts the shift lever to neutral, the traveling interlock is released, the buzzer stops, and the warning light goes out.

• Releasing load handling interlock When the operator gets in the operator’s seat and places all the load handling levers in neutral, the load handling interlock is released, the buzzer stops and the warning light goes out.

Note: • The buzzer will not sound when the interlock is activated, if the parking brake is in operation.

• The traveling interlock only shifts the transmission to neutral; it doesn’t engage the brakes.

• If, while the truck is going up a ramp for loading onto a trailer truck, the operator leaves the seat or rises up from the seat, or operates the truck from a position that does not press body weight on the seat, the traveling interlock is activated, the transmission is shifted to neutral, and the truck will roll back.

• Fasten the seat belt. Don’t leave or rises up from the operator’s seat while traveling.

• Don’t rest anything on the operator’s seat; otherwise the traveling interlock may fail to operate as it should.

• If the operator’s seat is replaced with a new one, use a genuine operator’s seat equipped with a seat switch.

• If the operator gets in the seat with the engine not running, and turns the starter switch to “ON”, the forks can be lowered in the same manner as usual.

- 140 -

9. ELECTRIC WIRING

2)

SEAT BELT INTERLOCK (OPTION) The seat belt interlock prevents the engine from starting up when the seat belt is correctly fastened. If the operator does not fasten the seat belt correctly in the operator’s seat, the lift truck won’t move nor operate. This helps prevent injury in the event of an accident.

Seat belt interlock operation: The engine won’t start up when the seat belt is correctly fastened after the operator seats himself in the operator’s seat and turns the ignition switch on.

If the seat belt is unfastened during driving, an alarm buzzer will sound. After about 3 seconds, the transmission is locked in neutral as well as the load handling system is also locked in neutral, with an alarm lamp turning on.

(If the seat belt is fastened again within 3 seconds, the alarm stops sounding and the truck will remain operative.)

Releasing the seat belt interlock: When the ignition switch is ON and you are in the operator’s seat, fasten the seat belt. This makes it possible to start up the engine.

If the seat belt switch is turned on before the operator sits in the seat, the engine won’t start up.

Unfasten the seat belt, sit in the seat, turn the ignition switch on, and fasten the seat belt again. This makes it possible to start up the engine.

If the interlock is activated due to the seat belt being unfastened during driving, make sure that you are seated properly and the ignition switch is turned on, return the shift lever into neutral, place the load handling levers in neutral and fasten the seat belt correctly.

Note: • Which is the first, turning on the ignition switch or seating in the operator’s seat, makes no difference to the operation of application and release of the seat belt interlock.

• If the seat belt is fastened before the operator seats himself, the engine won’t start up.

• If the ignition switch is turned off with the seat belt fastened, the engine won’t start up unless the seat belt is fastened again in the correct manner.

• On trucks with the seat belt interlock, the traveling and load handling interlock system will be activated if the seat belt is unfastened as well as the operator leaves his seat. Refer to the section about the travel and load handling interlock.

- 141 -

9. ELECTRIC WIRING

9.1.2 INSPECTING SEAT BELT INTERLOCK 1)

SEAT BELT INTERLOCK FUNCTION CONFIRMATION REQUIREMENT 1. Pull the parking brake lever and confirm that the change lever is in neutral.

2. Sit on the seat and turn the starter switch to “ON” with the seat belt removed.

3. Confirm that the meter panel displays the seat belt indication.

Note: Please refer to Figure 1.5 Combination Meter Panel (page 7).

4. Confirm that the meter panel displays the interlock indication.

5. Turn the starter switch to “START” and confirm that the engine is not start.

6. Return the starter switch to “ON” and set the seat belt.

7. Confirm that the meter panel does not display the seat belt indication.

8. Confirm that the meter panel does not display the interlock indication.

9. Turn the starter switch to “START” and confirm that the engine is start.

10. Confirm that the cargo handling lever (all) can be operated.

11. Confirm that lift truck can move back and forward.

12. Remove the seat belt and confirm the meter panel displays the seat belt indication.

13. Wait until the meter panel displays the interlock indication.

14. Confirm that the cargo handling lever (all) can not be operated.

15. Confirm that lift truck can not move back and forward.

- 142 -

9. ELECTRIC WIRING

2)

INSPECTING SWITCHES Disconnect the wiring connector from each switch.

Check for continuity (when the switch is ON) between the terminals of the switch using a multimeter.

(1) Seat switch Seat switch status

Continuity between terminals (1) and (2)

ON (occupied)

Continuity

OFF (empty)

No continuity

1 2 3

SW SEAT

(2) Seat belt switch

3)

(1) (2) (3)

LB

(1)

B

(2)

Br/W

(3)

LB B

Seat belt switch status

Continuity between terminals (2) and (3)

ON (occupied)

Continuity

OFF (empty)

No continuity

SW SEAT BELT Br/W

Fig. 9-a

INSPECTING RELAYS Disconnect the wiring connector from each relay.

(1) Interlock relay (5P) 1. C o n n e c t a 2 4 - V p o w e r s u p p l y t o terminals (1) and (2) and check whether there is continuity between terminals (3) and (4). There should be no continuity between terminals (3) and (5).

2. Disconnect the 24-V power supply from terminals (1) and (2) and check whether there is no continuity between terminals (3) and (4). There should be continuity between terminals (3) and (5).

3. Set the multimeter to the resistance measurement mode and apply the probes to terminals (1) and (2) to measure the resistance between them.

Standard resistance: 320Ω±10% (2) Interlock relay (4P) 1. Connect a 24-V power supply to terminals (1) and (2) and check whether there is continuity between terminals (3) and (4).

2. Disconnect the 24-V power supply from terminals (1) and (2) and check whether there is no continuity between terminals (3) and (4).

3. Set the multimeter to the resistance measurement mode and apply the probes to terminals (1) and (2) to measure the resistance between them.

Standard resistance: 320Ω±10% - 143 -

5

4 3

2

1

Fig. 9-b

4

2

3

1

Fig. 9-c

9. ELECTRIC WIRING

9.1.3 INSPECTING FUSES BOX 1) FUSE BOX The fuse box holds fuses which prevent the wire harnesses from burning due to overcurrent. The fuses are installed for each circuit. The fuses have different capacities for different circuits. Use caution when replacing the fuses.

10A 10A

Fig. 9-d 2) REPLACING FUSES

[Checking fuse]

CAUTION The fuses protect the electric circuit against overcurrent.

Use fuses of the specific ampere rating.

Check to see that the components in each circuit are operating properly. If every component in a circuit is not functioning, it indicates that the corresponding fuse is blown out. Replace the blown fuse with a spare fuse of the same capacity and color.

If some of the components in a circuit do not function properly, it suggests that a bulb has burnt out. Replace the burnt bulb with a new one of the same capacity. ① - ③ : They function regardless of the key switch position. ④ - ⑧ : They function when the key switch is in “ON”.

Normal fuse

Blown fuse

Fig. 9-e

LAMP HORN OPTION, REAR WORK LIGHT METER, ENGINE BACK LAMP, TURN SIGNAL TRANSMISSION TRANSMISSION CONTROLLER AUXILIARY

Fig. 9-f

- 144 -

- 145 -

Fig. 9.1 Locations of Electrical Parts

B

F/R SWITCH

LIGHTING SWITCH

HORN

KEY SWITCH

WIRE HARNESS SEAT BELT INTERLOCK

SWITCH STOP LAMP

A

KEY SW.

TURN SIGNAL SWITCH

LIGHTING SWITCH

SEAT BELT INTERLOCK SYSTEM

to WIRE HARNESS HEAD GUARD WIRE HARNESS FRONT

WIRE HARNESS FRONT

F/R SWITCH

HANDLE COLUMN COVER

to PARKING LEVER

WIRE HARNESS F/R SWITCH

LAMP TURN

COMBINATION METER

DETAIL B

WIRE HARNESS HEAD GUARD

LED HEAD LAMP

BKT RELAY

BONNET

SEAT

FLYWHEEL HOUSING

AIR CLEANER

DETAIL A

WR

LED REAR COMB LAMP

ALTERNATOR

to WIRE HARNESS REAR COMB LAMP

BR

to WIRE HARNESS REAR COMB LAMP

WATER TEMP. SENSOR

ALARM BUZZER

BACK BUZZER

STARTER

FRAME EARTH

BY L

to C

WIRE HARNESS SEAT BELT INTERLOCK

BATTERY TRAVEL AND LOAD HANDLING INTERLOCK SYSTEM (BKT BATTERY RELAY)

SAFETY OIL RELAY PRESSURE SW. GLOW PLUG

DIODE

WIRE HARNESS ENGINE

MOTOR STOPPER

FUSIBLE LINK WIRE

1/2 SOL. F/R SOL.

to MAIN VALVE

ATM CONTROLLER

to WIRE HARNESS HEAD GUARD

KEY SW.

to ACC

to B

YL

to BR BR

to R1

to R2

WIRE HARNESS SEAT SWITCH

WIRE HARNESS FRONT

9. ELECTRIC WIRING

9.2 WIRE HARNESS

9. ELECTRIC WIRING

A

FRONT

WIRE HARNESS ENGINE

B

RELAY BATTERY YL

L

DIODE UNIT

B

BY

BATTERY RELAY CONNECTING PROCEDURE VIEW A

TIMER 24V

RELAY

TRAVEL AND LOAD HANDLING INTERLOCK

RELAY

VIEW B

Fig. 9.2 Locations of Electrical Parts, Travel and Load Handling Interlock - 146 -

9. ELECTRIC WIRING

WIRE HARNESS ENGINE FRONT

B A

PLATE

LEFT SIDE OF TRUCK FRAME (viewed from inside the truck)

RELAY COVER

RELAY

SEAT BELT INTERLOCK TIMER 24V

Insert joint harness through body frame and plate

JOINT HARNESS

DETAIL A

VIEW B

Fig. 9.3 Locations of Electrical Parts, Seat Belt Interlock - 147 -

WIRE HARNESS OKM

PARKING LEVER

ER

WIRE HARNESS FRONT

ET

M

COMBINATION METER

WIRE HARNESS COMBINATION METER

CLAMP

BATTERY

9. ELECTRIC WIRING

Fig. 9.4 Locations of Electrical Parts, Combination Meter

- 148 -

YB

L

RG WR

YG

ＧＬ

B

Ｂ

ＬＲ ＷＹ

BrR

LW RW YW

Ｂ

Ｏ

Ｇ

ＹＲ

BrW

to F/R SWITCH

Ｗ ＬＷ

Ｌ

Ｂ

Ｌ

Ｙ Ｂ

Ｂ

RB

ＡＣ

２Ｂ

ＢＲ

２Ｗ

２Ｌ

Ｃ

３Ｌ

Ｒ ２Ｗ

５Ｂ Ｒ ５ＢＹ

Ｒ１

Ｒ

Ｂ

Ｒ２

to OPTIONAL ELECTRIC COMPONENTS

ＲＷ

Ｌ

Ｗ

Ｌ

to KEY SWITCH

to COMBINATION METER (to Fig.9.10:Wire Harness Combination Meter)

LW BR

to LIGHTING SWITCH

ＲＧ ２Ｒ

to HORN SWITCH

ＲＷ

Ｗ

Ｂ

ＲＧ

Ｂ ＧＲ ＲＷ

ＲＢ

ＧＲ

ＷＲ

ＷＲ

ＧＹ

ＧＬ

Ｒ

５Ｂ

Ｗ

５Ｂ

to WIRE HARNESS FOR OVERHEAD GUARD (LEFT)

ＬＧ

３Ｌ

５ＢＹ

ＧＬ

to HORN

ＧＢ

to TURN SIGNAL SWITCH

to HOUR METER

to CONTROL RESISTANCE

５ＢＷ

Ｙ

ＧＬ ＲＷ

Ｂ

to WIRE HARNESS FOR OVERHEAD GUARD (RIGHT)

ＧＹ

ＹＲ

２Ｂ ＧＢ ２Ｗ ２Ｌ

ＷＬ

２Ｒ

ＮＯＴＥ： Connector terminal position is viewed from terminal side.

ＧＬ

ＬＲ

BrR BrW

LG

to WIRE HARNESS ENGINE

２Ｂ

２ＷＲ ＧＲ

ＬＷ

ＲＧ

Ｇ ＲＷ

to CONTROLLER

ＢＲ ＹＷ ＹＬ Ｏ

ＲＧ ＬＷ

- 149 -

ＹＢ

Fig. 9.5 Wire Harness, Front Guard

ＢＬ ＷＹ

ＹＬ ＹＧ

to ALARM BUZZER

9. ELECTRIC WIRING

Fig. 9.6 Wire Harness, Engine

２Ｂ

２ＹＬ

Ｂ ＹＬ

Ｂ

Ｌｇ Ｂ

Ｖ

ＷＬ

ＢＬ

Ｒ

ＲＢ

YR BR

Ｖ

ＬＹ

ＬｇＲ

Ｂ

Ｐ

Ｇ ＹＲ Ｂ Ｌｇ

ＹＷ

３ＢＷ

Ｂ

５ＢＷ

to F/R RELAY

ＹＲ ＹＲ ＷY Ｖ

Ｂ

Ｃ

V B

Ｐ ＲＬ

Ｗ ３Ｂ

ＲＬ Ｂ

to BACK BUZZER

Ｂ

ＷＲ Y

ＹＧ

ＲＧ

Ｂ

ＲＢ ＲＷ Ｂ

ＧＬ ＲＬ

ＹＧ

３Ｌ

３ＢＹ

ＦＵＳＥ ＢＯＸ

１０Ａ

１０Ａ

１０Ａ

１０Ａ

１０Ａ

１０Ａ

１０Ａ

３０Ａ

ＲＢ ＲＷ Ｂ

ＧＲ ＲＬ

Ｙ

ＹＲ

Ｐ

ＬＷ

２Ｌ

ＧＢ

２Ｒ

ＣＯＮＴＲＯＬＬＥＲ

Ｔ／Ｍ

ＢＡＣＫ．ＴＵＲＮ

ＭＥＴＥＲ ＥＮＧＩＮＥ

ＯＰＴＩＯＮ

ＨＯＲＮ

ＬＡＭＰ

to REAR COMBINATION LAMP (LEFT)

to REAR COMBINATION LAMP (RIGHT)

to WATER TEMPERATURE SENDING UNIT

Ｒ

ＷＲ

to AIR CLEANNER (OPTION)

ＬＷ

Ｅ

３Ｂ

to ALTERNATOR

Ｂ

３Ｌ

to WARNING BUZZER

to SAFETY RELAY

Ｂ

to BACK LAMP RELAY

to SAFETY Ｂｒ RELAY

DIODE

DIODE

Ｇｙ ＬＲ

Ｇｙ Ｖ

Ｇｙ Ｌｇ

２Ｗ Ｂ

to REAR WORKING LAMP

to GLOW PLUG

to NEUTRAL RELAY

ＹＢ

to OIL PRESSURE SWITCH

Br WR BR Y

ＲＷ

ＬＢ Ｂ ＢｒＷ

to SEAT SWITCH

to LICENCE LAMP (OPTION)

to STARTER

３Ｒ

to FUEL LEVEL SENDING UNIT

Ｂ

to F/R RELAY

Ｂ

Ｙ

to WIRE HARNESS SEAT BELT INTERLOCK

Ｂ ＬＹ ＢＹ

ＬｇＲ Ｌ

to MOTOR STOPPER

to DIODE

Ｂ

Ｂ Ｌｇ

to ＧＹ FLASHER UNIT

Ｌ

ＹＬ

３Ｂ

Ｙ ＹＲ ＷＲ Ｂ

(RELAY 5)

Ｂ

to GROUND

２Ｌ ＧＢ ２Ｒ Ｐ ＹＲ ＬＷ

B O

to AUTOMATIC STOPPER RELAY

to FUSE BOX

to WIRE HARNESS FRONT GUARD

ＲＷ Ｇ ＲＧ ＬＷ ＹＢ ＹＧ ＧＷ ＹＷ ＷＲ ＹＬ Ｏ ＷＹ ＢＬ

to PRESSURE SWITCH FOR ACCUMULATOR

ＹＧ

BrW BrR

ＬＧ

to WIRE HARNESS FRONT

ＮＯＴＥ： Connector terminal position is viewed from terminal side.

５ＢＷ

５ＢＹ ３Ｌ

to WIRE HARNESS FRONT GUARD

to FUSIBLE LINK WIRE

to BRAKE LAMP SWITCH

ＧＷ

to TOR-CON OIL TEMPERATURE SENDING UNIT

ＷＲ Ｂ

to SOLENOID

Ｂ Ｂ Ｂ Ｇy Ｐ Ｗ Ｙ Ｗ

to TRANSMISSION CONTROL VALVE

to F/R SOLENOID

to 1ST/2ND SPEED SOLENOID

to BATTERY RELAY

３ＢＹ

３Ｌ

Ｒ ＬＧ Ｐ Ｂ ＬＢ ＹＲ

(TIMER and RELAY 6)

５Ｂ

to DIODE COUPLER

DIODE COUPLER

３Ｂ ３Ｌ Ｙ

- 150 -

ＬＲ ＧＲ WR ２Ｒ ２Ｂ ＹＲ ＷＬ ２Ｌ ２Ｗ ＧＢ ＧＹ ＧＬ Ｙ

３Ｒ

Ｙ

to RELAY TRAVELING AND LOADING INTERLOCK SYSTEM to WIRE HARNESS (RELAY 2) (RELAY 3) to TIMER FOR TRAVELING Ｐ Ｇ Ｗ ＹＲ ＹＬ ＢｒＲ ＹＲ ＹＲ AND LOADHANDLING Ｂ Ｂ Ｂ (RELAY 4) Ｂ Ｐ Ｙ Ｂ INTERLOCK Ｐ ＹＬ Ｐ to TIMER

9. ELECTRIC WIRING

Y/R B BR O

to WIRE HARNESS ENGINE

- 151 -

L/R

L

to LEAD WIRE INTERLOCK

BR/W

L/B

⑩ L/W

B Y/R

Y/R

BR/W R/G Y/R

G/R

to DIODE COUPLER

INSTALL

DIODE COUPLER

B

R/Y

Y/G

R/G

Y/G R/Y

Y/R R/G

R/G

G/R

⑥ to SEAT ON RELAY

BR/W

Y/R

Fig. 9.7 Wire Harness, Seat Belt Interlock L

B

R/Y

BR/Y

L/R

O

⑧ to INTERLOCK RELAY 2

BR/W L/B

Y/R

BR

Y/R G/R

⑦ to INTER LOCK RELAY 1

BR/W

Y/R

④ to SEAT BELT RELAY

ＮＯＴＥ： Connector terminal position is viewed from terminal side.

Please refer to Fig. 9.14 Circuit Diagram.

B

⑨ to SEAT BELT RELAY 2

Y/R BR/Y

L/B

L/W

② to TIMER UNIT CNB

⑤ to SEAT ON KEEP RELAY

③ to SEAT OFF RELAY

B

L/W

B

Y/R

① to TIMER UNIT CNA

to SEAT BELT INTERLOCK

9. ELECTRIC WIRING

9. ELECTRIC WIRING

to SEAT SWITCH B

L/B

BR/W to WIRE HARNESS SEAT BELT INTERLOCK

L

B

BR/W

L/B

L/R

L

L/R

to WIRE HARNESS ENGINE

ＮＯＴＥ： Connector terminal position is viewed from terminal side.

Fig. 9.8 Wire Harness, Seat Belt Interlock

to SEAT SWITCH

to SEAT SWITCH

B

L/B to FRAME

BR/W

B

B

L/B

BR/W

to SEAT BELT SWITCH

ＮＯＴＥ： Connector terminal position is viewed from terminal side.

Fig. 9.9 Wire Harness, Seat Switch - 152 -

9. ELECTRIC WIRING

to COMBINATION METER Y

BR YL

YG YB

L

RG WR

LW RW YW B

RB BrW

BrR

to WIRE HARNESS OKM

RB

YW RW ＬＷ BrR

ＢｒＷ

L B

YG

WR RG

Ｂ

ＹＬ

ＲＢ

Ｙ

BR YB

to WIRE HARNESS FRONT GUARD (to Fig.9.5:Wire Harness, Front Guard) ＮＯＴＥ： Connector terminal position is viewed from terminal side.

Fig. 9.10 Wire Harness, Combination Meter

to PARKING BRAKE SWITCH ＲＢ to BATTERY CAPACITY SENSOR

Ｂ

Ｙ to LEAD WIRE OKM ＹＬ

Ｂ

Ｙ

ＲＢ

to RADIATOR LEVEL SENSOR

ＹＬ

Ｂ

ＮＯＴＥ： Connector terminal position is viewed from terminal side.

Fig. 9.11 Wire Harness, OKM (OK Monitor) - 153 -

9. ELECTRIC WIRING

to WIRE HARNESS FOR FRONT COMBINATION LAMP

GW B

G to WIRE HARNESS FOR FRONT GUARD

to HEAD LIGHT

RY RG

B

B

RY

G

GW

RG

NOTE: Connector terminal position is viewed from terminal side.

Fig. 9.12 Wire Harness, Overhead Guard

to TRANSMISSION CONTROLLER

to SPEED SENSOR SELECTION SWITCH

to SPEED SENSOR

WB

NOTE: Connector terminal position is viewed from terminal side.

Fig. 9.13 Wire Harness, Transmission Control - 154 -

9. ELECTRIC WIRING

SEAT BELT INTERLOCK

① TIMER UNIT CNA

② TIMER UNIT CNB

③ SEAT OFF RELAY

④ SEAT BELT RELAY

⑤ SEAT ON KEEP RELAY

⑥ SEAT ON RELAY

⑦ INTERLOCK RELAY 1

⑧ INTERLOCK RELAY 2

⑨ SEAT BELT RELAY 2

⑩ DIODE COUPLER

TRAVELING AND LOADING INTERLOCK

Fig. 9.14 Circuit Diagram - 155 -

ISSUED: SEP., 2017

JB-1709001(AN) Printed in Japan