Hitachi Ex800h-5 Excavator Service Repair Manual

Hitachi EX750-5, EX800H-5

Excavator Service Manual

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EX750-5, EX800H-5

Workshop Manual

SECTION

1

GENERAL IMFORMATION

CONTENTS

Group 1 Precautions for Disassembling and Assembling

Precautions for Disassembling and Assembling...........................................W1-1-1

Maintenance Standard

Terminology..........................................W1-1-4

Group 2 Tightening

Tightening Torque Specification..............W1-2-1

Torque Chart..........................................W1-2-2

Piping Joint............................................W1-2-5

162W-1-1

GENERAL INFORMATION / Precautions for Disassembling and Assembling

PRECAUTIONS FOR DISASSEMBLING AND ASSEMBLING

Precautions for Disassembling and Assembling

• Clean the Machine

Thoroughly wash the machine before bringing it into the shop. Bringing a dirty machine into the shop may cause machine components to be contaminated during disassembling/assembling, resulting in damage to machine components, as well as decreased efficiency in service work.

• Inspect the Machine

Be sure to thoroughly understand all disassembling /assembling procedures beforehand, to help avoid incorrect disassembling of components as well as personal injury.

Check and record the items listed below to prevent problems from occurring in the future.

• The machine model, machine serial number, and hour meter reading.

• Reason for disassembly (symptoms, failed parts, and causes).

• Clogging of filters and oil, water or air leaks, if any.

• Capacities and condition of lubricants.

• Loose or damaged parts.

• Prepare and Clean Tools and Disassembly Area

Prepare the necessary tools to be used and the area for disassembling work.

• Precautions for Disassembling

• To prevent dirt from entering, cap or plug the removed pipes.

• Before disassembling, clean the exterior of the components and place it on a work bench.

• Before disassembling, drain gear oil from the reduction gear.

• Be sure to provide appropriate containers for draining fluids.

• Use matching marks for easier reassembling.

• Be sure to use the specified special tools, when instructed.

• If a part or component cannot be removed after removing its securing nuts and bolts, do not attempt to remove it forcibly. Find the cause(s), then take the appropriate measures to remove it.

• Orderly arrange disassembled parts. Mark and tag them as necessary.

• Store common parts, such as bolts and nuts with reference to where they are to be used and in a manner that will prevent loss.

• Inspect the contact or sliding surfaces of disassembled parts for abnormal wear, sticking, or other damage.

• Measure and record the degree of wear and clearances.

• Precautions for Assembling

• Be sure to clean all parts and inspect them for any damage. If any damage is found, repair or replace it.

• Dirt or debris on the contact or sliding surfaces may shorten the service life of the machine. Take care not to contaminate any contact or sliding surfaces.

• Be sure to replace O-rings, backup rings, and oil seals with new ones once they are disassembled. Apply a film of grease before installing.

• Be sure that liquid-gasket-applied surfaces are clean and dry.

• If an anti-corrosive agent has been used on a new part, be sure to thoroughly clean the part to remove the agent.

• Utilize matching marks when assembling.

• Be sure to use the designated tools to assemble bearings, bushings and oil seals.

• Keep a record of the number of tools used for disassembly/assembly. After assembling is complete, count the number of tools, so as to make sure that no tools are missing.

W1-1-1

GENERAL INFORMATION / Precautions for Disassembling and Assembling

Bleeding Air from Hydraulic System

When hydraulic oil is drained, the suction filter or the suction lines are replaced, or the removal and install ation of the pump, swing motor, travel motor or cylinder is done, bleed air from the hydraulic system in the following procedures:

• Bleeding Air from Hydraulic Pump

IMPORTANT:If the engine is started with air trapped in the hydraulic pump housing, damage to the pump may result. Be sure to bleed air before starting the engine.

• Remove the air bleeding plug from the top of the pump and fill the pump housing with hydraulic oil.

• After the pump housing is filled with hydraulic oil, temporarily tighten the plug. Then, start the engine and run at slow idle speed.

• Slightly loosen the plug to bleed air from the pump housing until hydraulic oil oozes out.

• After bleeding all the air, securely tighten the plug.

• Bleeding Air from Travel Motor/Swing Motor

• With the drain plug/hose on travel motor/swing motor removed, fill the motor case with hydraulic oil.

• Bleeding Air from Hydraulic Circuit

• After refilling hydraulic oil, start the engine. While operating each cylinder, swing motor and travel motor evenly, operate the machine under light loads for 10 to 15 minutes. Slowly start each operation (never fully stroke the cylinders during initial operation stage). As the pilot oil circuit has an air bleed device, air trapped in the pilot oil circuit will be bled while performing the above operation for approx. 5 minutes.

• Reposition the front attachment to check hydraulic oil level.

• Stop the engine. Recheck hydraulic oil level. Replenish oil as necessary.

W1-1-2

GENERAL INFORMATION / Precautions for Disassembling and Assembling

Floating Seal Precautions

1. In general, replace the floating seal with a new one.

If the floating is to be reused, follow these procedures:

(1) Keep seal rings together as a matched set with seal ring faces together. Insert a piece of cardboard to protect surfaces.

(2) Check seal ring face (C) for scuffing, scoring, corrosion, deformation or uneven wear.

(3) Check O-ring (B) for tears, breaks, deformation or hardening.

2. If incorrectly assembled, oil leakage or damage will occur. Be sure to do the following, to prevent trouble.

(1) Clean floating seal (A) and seal mounting bores with cleaning solvent. Use a wire brush to remove mud, rust or dirt. After cleaning, thoroughly dry parts with compressed air.

(2) Clean the floating seal and seal mounting bores, as dust on them tends to enter the floating seal when installing it.

(3) Check that the O-ring is not twisted, and that it is installed correctly on the seal ring.

(4) After installing the floating seal, check that seal face (C) is parallel with seal mounting bores ring face (D) by measuring the distances (C) and (D) at point (a) and (b), as illustrated. If these distances differ, correct the O-ring seating.

W1-1-3

GENERAL INFORMATION / Precautions for Disassembling and Assembling

MAINTENANCE STANDARD TERMINOLOGY

“Standard”

1. Dimension for parts on a new machine.

2. Dimension of components or assemblies adjusted to specification.

Both dimensions are shown with tolerances as necessary.

“Allowable Limit”

1. Normal machine performance cannot be accomplished after exceeding this limit.

2. Repair or replacement is required before reaching this limit.

Machine performance will decrease, and maintenance and down time expense will increase as machine operating hours accumulate. It is recommended that parts are repaired or replaced before reaching the “Allowable Limit”.

W1-1-4

GENERAL INFORMATION / Tightening

TIGHTENING TORQUE SPECIFICATIONS

NOTE:(1)Apply lubricant (e.g. white Zinc B dissolved into spindle oil) to bolts and nuts to stabilize friction coefficient of them.

(2)Make sure bolt and nut threads are clean before installing.

W1-2-1

(3)Apply LOCTITE to threads before installing and tightening swing bearing mounting bolts.

GENERAL INFORMATION / Tightening

TORQUE CHART

CAUTION:Use tools appropriate for the work to be done. Makeshift tools and procedures can create safety hazards. For loosening and tightening nuts and bolts, use the correct tools. Avoid bodily injury caused by slipping wrenches.

Bolt Types

Tighten nuts or bolts correctly to torque specifications. Four kinds of bolts, hexagon bolts T, H, M and socket bolt, each made of different material, are used. Make sure to employ the correct bolts and tighten them to specification when assembling the machine or components.

Specified Tightening Torque Chart

W1-2-2

Socket Bolt Hexagon T BoltHexagon H BoltHexagon M Bolt

GENERAL INFORMATION / Tightening

IMPORTANT:(1)Apply lubricant (i. e. white zinc B dissolved into spindle oil) to nuts and bolts to stabilize their friction coefficients.

(2)Torque tolerance is ± ± 10 %.

(3)Be sure to use bolts of correct length. Bolts that are too long cannot be tightened, as the bolt tip comes into contact with the bottom of the bolt hole. Bolts that are too short cannot develop sufficient tightening force.

(4)The torques given in the chart are for general use only. Do not use these torques if a different torque is given for a specific application.

(5)Make sure that the nut and bolt threads are clean before installing. Remove dirt or corrosion, if any.

Bolt Tightening Order

When tightening two or more bolts, tighten them alternately, as shown, to ensure even tightening.

W1-2-3

GENERAL INFORMATION / Tightening

Service Recommendations for Split Flange

IMPORTANT:(1)Be sure to clean and inspect sealing surfaces. Scratches/ roughness cause leaks and seal wear. Unevenness causes seal extrusion. If defects cannot be polished out, replace the component.

(2)Be sure to use only specified Orings. Inspect O-rings for any damage. Take care not to file Oring surfaces. When installing an O-ring into a groove, use grease to hold it in place.

(3)Loosely assemble split flange halves. Make sure that the split is centrally located and perpendicular to the port. Handtighten the bolts to hold the parts in place. Take care not to pinch the O-ring.

(4)Tighten bolts alternately and diagonally, as shown, to ensure even tightening.

(5)Do not use air wrenches. Using an air wrench often causes tightening of one bolt fully before tighten the others, resulting in damage to O-rings or uneven tightening of bolts.

Nut and Bolt Lockings

• Lock Plate

IMPORTANT:Do not reuse lock plates. Do not try to bend the same point twice.

• Cotter Pin

IMPORTANT:Do not reuse cotter pins. Match the holes in the bolt and nut while tightening, not while loosening.

• Lock Wire

IMPORTANT:Apply wire to bolts in the bolttightening direction, not in the boltloosening direction.

W1-2-4

GENERAL INFORMATION / Tightening

PIPING JOINT

Pipe Thread Connection/Union Joint Tightening

Torque Specifications

Union Joint

Metal sealing faces (4) and (5) of adaptor (1) and hose (2) fit together to seal pressure oil. Union joints are used to join small-diameter lines.

IMPORTANT:(1)Do not over-tighten union nut (3). Excessive force will be applied to metal sealing surfaces (4) and (5), possibly cracking adaptor (1). Be sure to tighten union nut (3) to specifications.

(2)Scratches or other damage to sealing surfaces (4) or (5) will cause oil leakage at the joint. Take care not to damage them when connecting/disconnecting.

NOTE:Tightening torque for the non-union type 37 ° male joint is the same as the 37 ° female union joint.

W1-2-5

GENERAL INFORMATION / Tightening

O-ring Seal Joint O-ring (6) seats against the end face of adaptor (7) to seal pressure oil.

IMPORTANT:(1)Be sure to replace O-ring (6) with a new one when reconnecting.

(2)Before tightening union nut (9), confirm that O-ring (6) is seated correctly in O-ring groove (8). Tightening union nut (9) with Oring (6) displaced will damage Oring (6), resulting in oil leakage.

(3)Take care not to damage O-ring groove (8) or sealing face (10). Damage to O-ring (6) will cause oil leakage.

(4)If union nut (9) is found to be loose, causing oil leakage, do not tighten it to stop the leak. Instead, replace O-ring (6) with a new one, then tighten union nut (9) after confirming that O-ring (6) is securely seated in place.

W1-2-6

GENERAL INFORMATION / Tightening

Screwed-In Connection

IMPORTANT:Many types of screwed-in connections are used for hose connections.

Be sure to confirm that the thread pitch and thread type (tapered or straight) are the correct type before using any screw-in connection.

Seal Tape Application

Seal tape is used to seal clearances between male and female threads, so as to prevent any leakage between threads.

Be sure to apply just enough seal tape to fill up thread clearances. Do not overwrap.

• Application Procedure

Confirm that the thread surface is clean, free of dirt or damage.

Apply seal tape around threads as shown. Wrap seal tape in the same direction as the threads.

Low-Pressure-Hose Clamp Tightening Torque

Low-pressure-hose clamp tightening torque differs depending on the type of clamp. See below for correct tightening torque of each type of low-pressure-hose clamp.

T-Bolt Type Band Clamp:

4.4 N m (0.45 kgf m, 3.25 lbf ft)

Worm Gear Type Band Clamp:

5.9 to 6.9 N m (0.6 to 0.7 kgf m, 4.3 to 5.1 lbf ft)

W1-2-7

GENERAL INFORMATION / Tightening

Connecting Hose

CAUTION:

(1)When replacing hoses, be sure to use only genuine Hitachi service parts. Using hoses other than genuine Hitachi hoses may cause oil leakage, hose rupture or separation of fitting, possibly resulting in a fire on the machine.

(2)Do not install hoses kinked. Application of high oil pressure, vibration, or an impact to a kinked hose may result in oil leakage, hose rupture or separation of fitting. Utilize print marks on hoses when installing hoses to prevent hose from being installed kinked.

(3)If hoses rub against each other, wear to the hoses will result, leading to hose rupture. Take necessary measures to protect hoses from rubbing against each other.

Take care that hoses do not come into contact with moving parts or sharp objects.

WRONGRIGHT

W105-01-01-011

WRONGRIGHT

Rubbing Against Each Other

WRONGRIGHT

W105-01-01-012

WRONGRIGHT

W105-01-01-013

W1-2-8

W105-01-01-014

Clamp Clamp

Rubbing

Rubbing

Clamp

Group 1 Cab

SECTION 2 UPPERSTRUCTURE

CONTENTS

Group 2 Counterweight Remove

Group 3 Pump Device Remove

Group 4 Control Valve

Group

Group 6 Pilot Valve

Remove and Install Right

Pilot Valve.........................................W2-6-1

Remove and Install Left

Pilot Valve.........................................W2-6-4

Remove and Install

Travel Pilot Valve...............................W2-6-7

Disassemble Right and Left

Pilot Valve.........................................W2-6-8

Assemble Right and Left

Pilot Valve.......................................W2-6-10

Disassemble Travel

Pilot Valve.......................................W2-6-14

Assemble Travel

Pilot Valve.......................................W2-6-16

Group 7 Pilot Shut-Off Valve

Remove and Install

Pilot Shut-off Valve............................W2-7-1

Disassemble Pilot Shut-off Valve.........W2-7-4

Assemble Pilot Shut-off Valve..............W2-7-6

Group 8 Shockless Valve

Remove and Install Front

Attachment Shockless Valve..............W2-8-1

Disassemble and Assemble

Shockless Valve

(Front Attachment)............................W2-8-4

Remove and Install

Travel Shockless Valve......................W2-8-7

Disassemble and Assemble

Travel Shockless Valve....................W2-8-10

Group 9 Solenoid Valve

Remove and Install

Two-Spool Solenoid Valve.................W2-9-1

Disassemble and Assemble

Two-Spool Solenoid Valve.................W2-9-3

162W-2-2

UPPERSTRUCTURE / Cab

REMOVE AND INSTALL CAB

Removal

1. Remove nuts (2) and seat (1).

:13 mm

2. Loosen bolts (5) behind the cab and bolts (6) in rear boxes (3 and 4). Remove rear boxes (3 and 4). :13 mm

3. Loosen bolts (8) to remove rear box lower cover (7). :13 mm

4. Remove filter (25). Loosen screws (9) to remove duct (10) from the cab.

UPPERSTRUCTURE / Cab

5. Remove cable connectors (11) located inside cab at the rear.

6. Disconnect wiper limit switch (12), cab light (13), speaker (14), antenna (15) and ground (17) located inside the cab. Remove washer vinyl hose(16) outside the cab.

7. Disconnect work light plug connector (18) outside the cab.

8. Remove cap (21) from duct cover (19). Loosen screws (20) to remove duct cover (19).

W2-1-2

UPPERSTRUCTURE / Cab

9. While pushing the mating face of duct (22) toward the rear side of the cab, remove duct (22).

10. Attach lifting straps to the top of the cab.

CAUTION:cab weight : 260 kg (573 lb)

11. Remove cab mounting bolts (23) and nuts (24).

12. Carefully remove the cab.

W2-1-3

Installation

UPPERSTRUCTURE / Cab

CAUTION: cab weight : 260 kg (573 lb)

1. Attach the lifting straps to the cab. Install the cab onto the frame.

2. Tighten bolts (23) and nut (24).

:17 mm

:49 N m (5 kgf m, 36 lbf ft)

:24 mm

:205 N m (21 kgf m, 152 lbf ft)

:8 mm

:64 N m (6.5 kgf m, 47 lbf ft)

3. Install duct (10) to the cab with screws (9). Install filter (25) into the duct.

:4.9 N m (0.5 kgf m, 3.6 lbf ft)

W2-1-4

W157-02-01-001 W157-02-01-010 W158-02-01-001 24

W162-02-01-001 23 25 10

9

UPPERSTRUCTURE / Cab

5. Reconnect wiper limit switch (12), cab light (13), speaker (14) antenna (15) and ground (17) located in the cab. Reinstall washer vinyl hose (16) outside the cab.

:19.5 N m (2 kgf m, 14.5 lbf ft)

6. Reconnect work light plug connector (18) outside the cab.

7. Install rear box lower cover (7) with bolts (8).

:13 mm

:19.5 N⋅m (2 kgf ⋅m, 14.5 lbf⋅ft)

8. Install rear boxes (3 and 4) with bolts (5 and 6). :13 mm

:19.5 N⋅m (2 kgf ⋅m, 14.5 lbf⋅ft)

W2-1-5

UPPERSTRUCTURE / Cab

9. While pushing duct (22) to the front of the cab, insert duct (22) into the front duct until the mating faces come in contact with each other.

10. Install duct cover (19) with screws (20). Install caps (21).

W2-1-6

11. Secure seat (1) with nuts (2). :13 mm

N m (2 kgf m, 14.5 lbf ft)

UPPERSTRUCTURE / Cab

DIMENSIONS OF THE CAB GLASS

NOTE:Material:JIS-R3211,R3212

or equivalent

UPPERSTRUCTURE / Cab

No polish chamfering are required in this range.

UPPERSTRUCTURE / Counterweight

REMOVE AND INSTALL COUNTERWEIGHT

Removal

CAUTION:Counterweight weight: 12500 kg (27560 lb)

1. Attach wire ropes with shackles to the lifting lugs on the top of the counterweight. Take out any slack on the wire ropes by applying tension slowly with a crane.

CAUTION:Use care to prevent hand injury from the power wrench reaction bar.

2. Use a power wrench to remove bolts (7), nuts (10), stoppers (8) and washers (6 and 9).

:65 mm

3. Loosen bolts (1) to remove spring washers (2), stoppers (3) and spacers (4). Remove shims (5) if equipped.

:36 mm

4. Remove the counterweight.

W162-02-02-001

W162-02-02-002

UPPERSTRUCTURE / Counterweight

Installation

CAUTION:Counterweight weight: 12500 kg (27560 lb)

1. Attach wire ropes with shackles to the lifting lugs on the top of the counterweight.

CAUTION:Never allow anyone under the lifted counterweight.

2. Lift the counterweight. With the bosses on the back face of the counterweight aligned with holes on the frame, install the counterweight.

CAUTION:Use care to prevent hand injury from the power wrench reaction bar.

IMPORTANT:Apply a lubricant to bolts (7) before installing. Install stoppers (8) with flanges positioned downward.

3. Install bolts (7), nuts (10), stoppers (8) and washers (6 and 9). Tighten bolts (7) using a power wrench.

:65 mm

:2750 N m (280 kgf m, 2025 lbf ft)

4. Install shims (5), spacers (4), stoppers (3), and spring washers (2) and bolts (1). Detach the wire ropes and shackles.

:36 mm

:390 N⋅m (40 kgf ⋅m, 290 lbf⋅ft)

W2-2-2

UPPERSTRUCTURE / Pump Device

REMOVE AND INSTALL PUMP DEVICE

CAUTION:Escaping fluid under pressure can penetrate the skin, causing serious injury. Avoid this hazard by relieving pressure before disconnecting hydraulic lines.

Hydraulic oil may be hot after operation. Hot hydraulic oil may spout, possibly causing severe burns. Be sure to wait for oil to cool before starting any repair work.

The hydraulic oil tank cap may fly off by remaining pressure if removed quickly. Slowly loosen the cap to completely release any remaining pressure.

Preparation

1. After stopping the engine, move the control levers several times to release any pressure remaining in the system.

2. Rotate the hydraulic oil tank cap approx. 30° counterclockwise to release trapped air in the hydraulic oil tank.

Removal

1. Disconnect all hydraulic lines and electrical cables from the pump.

:22 mm, 27 mm

:8 mm, 14 mm

2. Place a block (100 mm square, approx. 30 mm thick) underneath the engine flywheel housing.

CAUTION:Pump device weight: 445 kg (980 lb)

3. Remove the pump device mounting bolts and rear side engine mounting bolts to remove the pump device.

:36 mm, 16 mm

Installation

1. Install the pump with the mounting bolts.

2. Connect all hydraulic lines and electrical cables to the pump.

3. Bleed air trapped inside the pump. (Refer to page W1-1-2.)

IMPORTANT:After installing the pump, be sure to perform break-in operation to prevent seizure.

Break-In Operation Process:

1. Start the engine and run at slow idle speed for 20 minutes. Check for oil leaks while running at slow idle.

2. Increase the engine speed to the fast idle speed. Raise and lower the boom for 20 minutes repeatedly. (Do not operate the control levers quickly. Slowly move the levers to full stroke.)

W2-3-1

Engine Rear Side Mounting Bolt

UPPERSTRUCTURE / Pump Device

UPPERSTRUCTURE / Pump Device

Disassemble Pump Transmission

• Before starting any repair work, thoroughly read all “Precautions for Disassembling and Assembling” (W1-1-1).

CAUTION:Pump device weight: 145 kg (320 lb)

1. Place casing (1) on a work bench with the main pump mounting side facing downward.

2. Remove bolts (10). :8 mm

CAUTION:Pump device weight: 145 kg (320 lb)

3. Re-position casing (1) on the work bench so that the engine mounting side faces downward.

NOTE:At this time, lay two wooden blocks (100 mm high) under the casing so that the blocks are not under cartridges (9 and 13).

4. Attach metal protector (dia 30 mm) to top of sleeve (3) and tap the protector over top of sleeve (3) with a plastic hammer until gear (5) comes in contact with casing (1). Then, cartridge (9) and bearing (7) are pushed out of casing (1).

CAUTION:Pump device weight: 145 kg (320 lb)

5. Lay two wooden blocks (150 mm high) on the work bench. Place casing (1) on the wooden blocks with the main pump mounting side facing downward.

6. Remove cartridge (9) from casing (1). Remove Oring (8) from cartridge (9).

7. Attach metal protector (dia 25 mm) to top of sleeve (3) and tap the protector over top of sleeve (3) with a plastic hammer until gear (5) comes in contact with casing (1). Remove sleeve (3) from the outer race of bearing (7).

8. Using a puller, remove the outer race of bearing (7).

9. Remove retaining ring (6) from sleeve (3).

10. Attach metal protector (dia. 30 mm) to top of sleeve (3) and tap the protector over top of sleeve (3) with a plastic hammer to remove sleeve (3) and bearing (2) from casing (1).

11. Using a press, remove bearing (2) from sleeve (3).

12. Remove retaining ring (4) from sleeve (3).

13. Remove bolts (11) and cartridge (13). :17 mm

14. Remove oil seal (12) and o-ring (14) from cartridge (13).

CAUTION:Pump transmission weight: 140 kg (310 lb)

15. Lay two wooden blocks (150 mm high) on the work bench. Place casing (1) on the wooden blocks with the engine mounting side facing downward.

16. Attach metal protector (dia 90 mm) to top of gear (16). Using a press, push gear (16) out of casing (1).

17. Take gear (5) out of casing (1).

18. Using a press or puller, remove bearings (15 and 17) from gear (16).

W2-3-3

UPPERSTRUCTURE / Pump Device

ASSEMBLE PUMP TRANSMISSION

W2-3-4

W162-02-03-001

1 - Casing6 - Retaining Ring10 - Bolt (5 Used)14 - O-Ring

2 - Bearing7 - Bearing11 - Bolt (8 Used)15 - Bearing

3 - Sleeve8 - O-Ring12 - Oil Seal16 - Gear

4 - Retaining Ring9 - Cartridge13 - Cartridge17 - Bearing

5 - Gear

UPPERSTRUCTURE / Pump Device

Assemble Pump Transmission

1. Press bearings (15 and 17) onto gear (16).

2. Install retaining ring (4) to sleeve (3).

3. Press bearing (2) onto sleeve (3).

4. Install gear (5) into casing (1).

IMPORTANT:Press bearing (2) into casing (1) until the end face of bearing (2) is flush with the stepped face in the casing bore.

5. With splines on sleeve (3) and gear (5) aligned, press sleeve (3) with bearing (2) into casing (1).

CAUTION:Assembly weight of casing (1), gear (5), etc.: 125 kg (276 lb)

6. Turn casing (1) over.

7. Install retaining ring (6) to sleeve (3).

8. After centering the outer and inner races of bearing (7), press the outer race of bearing (7) into casing (1).

9. Install O-ring (8) around cartridge (9).

10. Install cartridge (9) in casing (1) with bolts (10).

:13 mm

:20 N m (2 kgf m, 14.5 lbf ft)

11. Press gear (16) into casing (1) so that gear (16) meshes with gear (5).

12. Attaching a protector on oil seal (12), press oil seal (12) into cartridge (13).

13. Apply grease on the inner lip of oil seal (12).

14. Install O-ring (14) in cartridge (13).

15. Install cartridge (13) in casing (1) with bolts (11).

:17 mm

:49 N m (5 kgf m, 36 lbf ft)

CAUTION:Pump transmission weight: 145 kg (320 lb)

16. Check that bearing (2) and sleeve (3) are correctly installed in casing (1) by softly tapping bearing (2) with a plastic hammer.

W2-3-5

(Blank)

UPPERSTRUCTURE / Pump Device

W2-3-6

UPPERSTRUCTURE / Pump Device

REMOVE AND INSTALL MAIN PUMP

CAUTION:Escaping fluid under pressure can penetrate the skin, causing serious injury. Avoid this hazard by relieving pressure before disconnecting hydraulic lines.

Hydraulic oil may be hot after operation. Hot hydraulic oil may spout, possibly causing severe burns. Be sure to wait for oil to cool before starting any repair work.

The hydraulic oil tank cap may fly off by remaining pressure if removed quickly. Slowly loosen the cap to completely release any remaining pressure.

Preparation

1. After stopping the engine, move the control levers several times to release any pressure remaining in the system.

2. Rotate the hydraulic oil tank cap approx. 30° counterclockwise to release trapped air in the hydraulic oil tank.

Removal

1. Disconnect all hydraulic lines and electrical cables from the pump.

:22 mm, 27 mm

:8 mm, 14 mm

CAUTION:Main pump weight: 300 kg (661 lb)

2. Remove the pump mounting bolts to remove the pump.

:36 mm

Installation

1. Install the pump with the mounting bolts.

2. Connect all hydraulic lines and electrical cables to the pump.

3. Bleed air trapped inside the pump. (Refer to page W1-1-2.)

Break-In Operation Process:

Mounting Bolt

W2-3-7

T162-03-01-001

1. Start the engine and run at slow idle speed for 20 minutes. Check for oil leaks while running at slow idle.

2. Increase the engine speed to the fast idle speed. Raise and lower the boom for 20 minutes repeatedly. (Do not operate the control levers quickly. Slowly move the levers to full stroke.)

UPPERSTRUCTURE / Pump Device

UPPERSTRUCTURE / Pump Device

NOTE:Parts (6 to 9, 12 to 18, 20 to 41, 55, and 56) in housing (61) are the same as those used in housing (19).

W2-3-9

UPPERSTRUCTURE / Pump Device

UPPERSTRUCTURE / Pump Device

Disassemble Main Pump

• Before starting any repair work, thoroughly read all “Precautions for Disassembling and Assembling” (W1-1-1).

IMPORTANT:Do not remove screws (13 and 48) and nuts (12 and 49). If removed, the pump set flow rate may be changed.

1. Remove two plugs (32) and O-rings (31) to drain hydraulic oil from the pump.

:36 mm

2. Remove socket bolt (22) and regulator (21). Remove A sensors (30) (two places).

:6 mm

IMPORTANT:Take care not to allow valve plates (42 and 58) to drop when separating housing (19) assembly, cover (45) assembly, cover (71) assembly, and housing (61) assembly.

3. Insert a steel bar or pipe into the pump mounting bolt holes in covers (11 and 65). While holding the bar or pipe to prevent the pump assembly from rotating, loosen socket bolts (10 and 66) to separate housing (19) assembly, cover (45) assembly, cover (71) assembly and housing (61) assembly.

At this time, remove O-rings (44, 59, 60, and 74 to 76), spring pins (52 and 70), and filters (53 and 69).

:17 mm

4. Remove booster (50), coupling (51), valve plate (42) and pin (54) from cover (45). Remove valve plate (58) and pin (68) from cover (71).

NOTE:Do not remove bearing (43, 57) unless required.

5. Remove cylinder blocks (41), springs(40), spacers (39), spherical bushings (38), retainers (37) plungers (36), and shoes (35) from housings (19 and 61).

6. Loosen socket bolts (1 and 64) to remove covers (2 and 63) and O-rings (3 and 62). Remove oil seal (4) from cover (2).

:6 mm

7. Tap covers (11 and 65) with a plastic hammer to remove from housings (19 and 61). Remove Orings (27) and spring pins (14).

8. Remove swash plates (33) and shoe plates (55) from housings (19 and 61).

NOTE:Do not remove feedback links (56) unless required.

9. Tap with a plastic hammer to remove shafts (5 and 67) from covers (11 and 65).

10. Remove retaining rings (9), spacers (8), bearings (7) and spacers (6) from shafts (5 and 67)

IMPORTANT:LOCTITE is applied to the joint between servo piston (23) and tilt pin (20). Take care not to damage servo piston (23) when disassembling.

11. Remove stoppers (16), stoppers (26), servo pistons (23) and tilt pins (20) from housings (19 and 61).

W2-3-11

UPPERSTRUCTURE / Pump Device

NOTE:Parts (6 to 9, 12 to 18, 20 to 41, 55, and 56) in housing (61) are the same as those used in housing (19).

UPPERSTRUCTURE / Pump Device

Assemble Main Pump IMPORTANT:Apply LOCTITE (medium adhesive) to the joint between servo piston (23) and tilt pin (20).

1. Install A sensors (30), tilt pins (20), servo pistons (23), O-rings (18 and 24), backup rings (17 and 25) and stoppers (16 and 26) into housings (19 and 61).

:6 mm

:29 N m (3 kgf m, 22 lbf ft)

2. Heat bearing (7). Install spacers (6), bearings (7), spacers (8) and retaining rings (9) onto shafts (5 and 67).

3. Install pins (14), O-rings (15 and 27) to covers (11 and 65). Install covers (11 and 65) to housings (19 and 61).

IMPORTANT:Install feedback link (56) to swash plate (33) with the link hole connected to tilt pin (20).

4. Install shoe plate (55) to swash plate (33). Install swash plates (33) into housings (19 and 61) so that the swash plate joins with tilt pin (20).

NOTE:After installing swash plate (33), make sure that the swash plate can be moved smoothly by hand.

5. Press shafts (5 and 67) in covers (11 and 65). Install oil seals (4), O-rings (3 and 62) to covers (2 and 63). Install covers (2 and 63) to covers (11 and 65) with socket bolts (1 and 64).

:6 mm

:29 N m (3 kgf m, 22 lbf ft)

6. Install springs (40), spacer (39), spherical bushing (38), plungers (36), retainer (37) and shoes (35) to cylinder block (41). Install the cylinder blocks onto shafts (5 and 67) while aligning splines.

IMPORTANT:Apply greae to the valve plate (42).

7. Install spring pins (52), filter (53), pin (54), valve plate (42) and O-rings (44) to cover (45).

NOTE:When installing valve plate (42), align the pin hole position with pin (54).

8. Install housing (19) assembly to cover (45) with socket bolts (10).

:17 mm

:630 N m (64 kgf m, 463 lbf ft)

9. Install coupling (51) and booster (50) to cover (45).

IMPORTANT:Apply a film of grease to valve plate (58).

10. Install spring pins (70), filter (69), pin (68), valve plate (58) and O-rings (60, 59, 74, 75, and 76) to cover (71).

NOTE:When installing valve plate (58), align the pin hole position with pin (68).

11. Install housing (61) to cover (71). Then, install them to housing (19) assembly with socket bolts (66).

:17 mm

:630 N⋅m (64 kgf ⋅m, 463 lbf⋅ft)

12. Install regulator (21) onto housing (19) with socket bolts (22) so that the regulator feedback lever joints with tilt pin (20).

:6 mm

:29 N⋅m (3 kgf ⋅m, 22 lbf⋅ft)

13. Install O-rings (31) and plugs (32).

:36 mm

:165 N m (17 kgf m, 123 lbf ft)

W2-3-13

UPPERSTRUCTURE / Pump Device

MAINTENANCE STANDARDS

1. Clearance between Plunger (36) Outer Diameter (d) and Cylinder Block (41) Bore Diameter (D).

D dUnit : mm (in)

StandardAllowable Limit 0.047 (0.002)0.094 (0.004)

2. Free Length (L) of Spring (40) Unit : mm (in)

StandardAllowable Limit

(1.95)48.0 (1.89)

3. Clearance (e) between Plunger (36) and Shoe (35) and Thickness (t) of Shoe (35).

eUnit : mm (in)

StandardAllowable Limit 0 to 0.1 (0 to 0.004)0.35 (0.014)

tUnit : mm (in)

StandardAllowable Limit 6.5 (0.26)6.3 (0.25)

4. Height difference from the reverse face of retainer (37) to the top of spherical bushing (38)

H hUnit : mm (in)

StandardAllowable Limit 16.5 (0.65)15.5 (0.61)

W2-3-14

(Blank)

UPPERSTRUCTURE / Pump Device

W2-3-15

UPPERSTRUCTURE / Pump Device

DISASSEMBLE REGULATOR

UPPERSTRUCTURE / Pump Device

Disassemble Regulator

• Before starting any repair work, thoroughly read all “Precautions for Disassembling and Assembling” (W1-1-1).

1. Remove pump control solenoid valve (23).

:32 mm

2. Loosen socket bolts (25) to remove valve cover (24).

:5 mm

3. Remove O-ring (29), valve seat (30), steel ball (31), and stopper (32) from casing (1).

4. Remove O-ring (22), sleeve (21), and pilot piston (20) from casing (1).

5. Remove plug (11) to remove feedback lever (18), pin (17), sleeve (19), and spool (16).

:6 mm

NOTE:Feedback lever (18) and pin (17) will come off at the same time .

6. Loosen socket bolts (7) to remove cover (6).

:5 mm

IMPORTANT:Do not remove screw (8) and nut (9). If removed, the pump flow rate setting may be changed.

7. Using forcing bolt (M4), remove stopper (4). Then, remove spring (3) and spring seat (2).

8. Remove O-ring (38), valve seat (37), steel ball (36), and stopper (35) from casing (1).

W2-3-17

UPPERSTRUCTURE / Pump Device

ASSEMBLE REGULATOR

W2-3-18

UPPERSTRUCTURE / Pump Device

Assemble Regulator

1. Install stopper (35), steel ball (36), valve seat (37) and O-ring (38) into casing (1).

2. Install sleeve (19) and spool (16) into casing (1). Then, install feedback lever (18) to sleeve (19) with pin (17).

NOTE:Take care not to mistake the installing direction of sleeve (19) and spool (16).

3. Install O-ring (10) around plug (11). Align the pin holes of feed back lever (18) and casing (1). Then, install plug (11) with O-ring (10) into casing (1).

:6 mm

:19 N m (2 kgf m, 15 lbf ft)

NOTE:After installing plug (11), check that the feedback lever (18) moves smoothly.

4. Install spring seat (2), spring (3), stopper (4) and O-ring (5) into casing (1). Install cover (6) with socket bolts (7).

:4 mm :12 N m (1.2 kgf m, 8.7 lbf ft)

5. Install pilot piston (20), sleeve (21), and O-ring (22) into casing (1).

6. Install stopper (32), steel ball (31), valve seat (30) and O-ring (29) into casing (1).

7. Install pump control solenoid valve (23) to valve cover (24). Install valve cover (24) to casing (1) with socket bolts (25).

:32 mm

:44 N m (4.5 kgf m, 33 lbf ft)

:4 mm

:12 N m (1.2 kgf m, 8.7 lbf ft)

W2-3-19

UPPERSTRUCTURE / Pump Device

UPPERSTRUCTURE / Pump Device

Remarks

1Housing1

2Flange1

3Oil Seal1Apply grease to oil seal lip when installing.

5Retaining Ring1

6Seal2Apply grease to seal when installing.

7Cover1

9Backup Ring2Apply grease to backup ring when installing.

10Key2

12O-Ring2Apply grease to O-ring when installing.

13Gear1

14Gear1

15Washer4

16Bolt4 :1739 to 444 to 4.529 to 33

26Bushing2Apply a film of hydraulic oil to bushing when installing.

27Bushing2Apply a film of hydraulic oil to bushing when installing.

W2-3-21

(Blank)

UPPERSTRUCTURE / Pump Device

W2-3-22

UPPERSTRUCTURE / Control Valve

REMOVE AND INSTALL CONTROL VALVE

CAUTION:

1.Escaping pressure hydraulic oil can penetrate the skin or eyes, causing serious injury. Avoid this hazard by relieving pressure before disconnecting hydraulic lines.

2.Hydraulic oil may be hot after operation. Hot hydraulic oil may spout, possibly causing severe burns. Be sure to wait for oil to cool before starting work.

3.The hydraulic oil tank cap may fly off due to internal pressure if turned quickly. Slowly turn the cap to release internal pressure before completely removing the cap.

Preparation

1. Park the machine on firm and level surface. Lower the front attachment to the ground.

2. Stop the engine. Move all control levers to release any pressure remaining in the system.Slowly turn the hydraulic oil tank cap approx. 30 degrees counterclockwise to release any remaining pressure from the hydraulic oil tank. Refer to “Bleed Pressure from Hydraulic Circuit” on page W1-1-2.

3. Remove the cap and connect a vacuum pump. Operate the vacuum pump constantly to maintain the negative pressure in the hydraulic oil tank.

NOTE:Keep the vacuum pump running continuously while working.

W2-4-1

Hitachi EX750-5, EX800H-5

Excavator Service Manual

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