7.11 Possible failures of FDA and guidelines for troubleshooting

Oil pressure loss in transmission hydraulic system

Breakdown of gear wheel pump in transmission hydraulic system Replace gear wheel pump of transmission hydraulic system

Transmission hydraulic system pump actuator Engage transmission hydraulic system pump actuator

Damaged parts of transmission hydraulic system pump actuator Replace damaged parts of transmission hydraulic system pump actuator

High oil pressure in transmission hydraulic system

Oil does not corresponds to the current season (ambient temperature) Fill in corresponding seasonal oil Deadlock of distributor-filter bypass valve Rinse distributor-filter bypass valve

Increased noise

Insufficient oil level in transmission Check oil level in transmission as indicated in section 6 “Maintenance service”. Refill oil up to the required level if necessary.

Wear or breaking of bearings of other transmission components Replace bearings

7.11 Possible failures of FDA and guidelines for troubleshooting

List of possible failures of front driving axle and guidelines for troubleshooting are shown in Table 7.11. Table 7.11

Failure, external manifestations, cause Troubleshooting

increased wear and delaminating of front tires

Faulty toe-in Adjust toe-in as indicated in section 6 “Maintenance service”.

Noncompliance of pressure in tires to the recommended standards

Adjust pressure in tires as indicated in subsection 4.2.8 “Choice of optimal inflation pressure of tire depending on operating conditions and tractor axle load, and tires operating rules”

Drive clutch does not transmit torque

Pressure loss in clutch booster Disassemble distribution valve, rinse case and spool Failure of system electrics Detect and correct trouble in ECS of FDA

Insufficient value of torque transferred

Low pressure in transmission hydraulic system Adjust pressure in transmission hydraulic system up to the value 0.9 to 1.0 MPa Increased leakage in drive control hydraulic system: - wear of O-rings of piston and drum; - wear of mating surfaces sleeve –drum hub, drum – piston; Replace O-rings Replace worn-out parts

- wear of disk packs. Replace worn-out parts

Drive does not operate in automated mode

In automated mode FDA drive can not be engaged when guide wheels are in “forward” position Detect and correct trouble in ECS of FDA

FDA drive is permanently engaged in automated mode (can not be disengaged when guide wheels are turned) Disconnect switch of FDA drive automatic switching-on sensor got out of adjustment Detect and correct trouble in ECS of FDA

Adjust disconnect switch of FDA drive automatic switching-on sensor

Increased noise generated by main gear

Increased clearance in driving gear bearing of reducing gear and differential Check and adjust if necessary conical bearing preload of central gearbox and differential driving gear, as indicated in subsection 3.12.2 “Central gearbox”

Lateral clearance space in main twin of central gearbox got out of adjustment Adjust lateral clearance space in main twin of central gearbox

Breaking of differential bearings Disassemble, replace failed items

Table 7.11 finished Failure, external manifestations, cause

Troubleshooting

Oil leakage through wheel-hub drive

Worn-out or damages wheel-hub drive flange sealings Replace sealings Increased clearance in wheel-hub drive flange bearings Make adjustment as indicated in section 6 “Maintenance service”

Increased oil level in wheel-hub drive Set the required level of oil in wheel-hub drive as indicated in section 6 “Maintenance service”

Oil leakage through central gearbox

Worn-out or damages flange sealings of driving gear of main gear Replace sealing

Oil leakage from FDA beam

Worn-out or damages double hinge pivot sealing Replace sealing

ATENTION: AFTER ANY DISMOUNTING OF STEERING LINK AND ITS SUBSEQUENT INSTALLATION, HAVING MADE ALL NECESSARY ADJUSTMENTS, TIGHTEN TWO CASTLE NUTS 20 1.5 OF BALL PINS WITH TORQUE FROM 100 TO 140 , AND FASTEN THEM BY COTTER (WITH MATCHING OF NUT SLOT AND OPENING OF BALL PIN TURNING OFF OF THE NUT IT IS NOT ALLOWED) AND TWO LOCKING NUTS 27 1.5 (WITH THE LEFT AND RIGHT-HAND THREAD) OF STEERING LINK PIPE WITH TORQUE OF 100 TO 140 N·M!

7.12 Possible failures of hydrostatic steering control and guidelines for troubleshooting

List of possible failures of hydrostatic power steering and guidelines for troubleshooting are shown in Table 7.12. Table 7.12

Failure, external manifestations, cause Troubleshooting

Great efforts at steering wheel

Pressure loss or insufficient pressure in steering control hydraulic system (it must be from 14.0 to14.5 MPa (steering wheel is turned up to the stop)) due to the following reasons: - HSC wasn’t bled Bleed air from the HSC hydraulic system by turning steering wheel with movement of guide wheels from left-most to the right-most position (stop stop-to-stop position) for 2-3 times

- faulty adjustment of dosing pump pressure relief valve (low pressure)

- faulty feed pump

Hard abrasion or blocking up in steering column mechanical components

Increased torque of FDA reducing gear turn Contact the dealer. Adjust pressure relief valve for the required pressure1). Operation is performed only by maintenance department

Contact the dealer. Pump does not generate pump due to low efficiency coefficient Stop abrasion in steering column, for which perform the following: - loosen upper nut; - lubricate friction surfaces of plastic bushings; - eliminate contact of universal-joint fork with steering column bracket walls Make repair of FDA

Steering wheel is rotating without turn of steerable wheels

There is no oil in the tank Fill the tank with oil up to the required level and bleed air from the hydraulic system of HSC

Disadjustment of dosing pump valves. Adjusting pressure of pressure-relief valve exceeds pressure of anti-shock valves Contact the dealer. Adjust pressure-relief valve and anti-shock valves up to the required pressure. Operation is performed only by maintenance department

1)

Worn-out sealing of hydraulic cylinder piston Repair or replace hydraulic cylinder

When steering wheel is rotated the steerable wheels turn right-about

Incorrect high-pressure hose connection to the corresponding pocket of dosing pump or hydraulic steering cylinder Connect high-pressure hoses to the pocket corresponding to direction of steering wheel turning Wrong adjustment of the dosing pump safety valve (adjusted for low pressure or hung up in the open position due to clogging) Contact the dealer. Washing and adjustment of safety valve up to the required pressure shall be carried out by the maintenance department 1)

Table 7.12 continued Failure, external manifestations, cause

Troubleshooting

Steering if too slow and too hard in course of quick turning of steering wheel

Hard abrasion or blocking up in steering column mechanical components Stop abrasion in steering column, for which perform the following: - loosen upper nut; - lubricate friction surfaces of plastic bushings; - eliminate contact of universal-joint fork with steering column bracket walls

"Motoring" of the dosing pump (steering wheel continue to rotate after turning)

Gripping of sleeve with spool (perhaps due to dirt accumulation) Contact the dealer. Rinse of dosing-pump components is required. Assembly and check of operability should be is performed only by maintenance department in accordance with manufacturer’s instruction 1)

Spool recentering springs of dosing pump have lost spring power or are broken Contact the dealer. Replacement of springs, assembly and check of operability should be is performed only by maintenance department in accordance with manufacturer’s instruction 1)

Permanent adjustment of steering wheel is required (steering wheel does not follow selected direction)

Spool recentering springs of dosing pump have lost spring power or are broken Contact the dealer. Replacement of springs, assembly and check of operability should be is performed only by maintenance department in accordance with manufacturer’s instruction 1)

One of anti-shock valves setting springs is broken or gerotor twin is worn-out

Worn-out sealing of hydraulic cylinder piston Contact the dealer. Replacement of faulty components assembly and check of operability should be is performed only by maintenance department in accordance with manufacturer’s instruction 1) Replace faulty components of cylinder

Increased clearance of steering wheel

Cone-shaped pins of HSC hydraulic cylinders have not been tightened Tighten pin nuts as indicated in section 6 “Maintenance service”

Clearance in steering joints Correct clearance in steering joints, as indicated in section 6 “Maintenance service”

Worn-out steering column splines shank Replace lower universal-joint fork

Worn-out steering column cardan shaft Spool recentering springs of dosing pump have lost spring power or are broken Replace cardan shaft

Contact the dealer. Replacement of springs, assembly and check of operability should be is performed only by maintenance department in accordance with manufacturer’s instruction 1)

Table 7.12 continued

Failure, external manifestations, cause Troubleshooting

Wobbling of steerable wheels when moving

Cone-shaped pins of HSC hydraulic cylinders have not been tightened Tighten pin nuts as indicated in section 6 “Maintenance service” Clearance in steering joints Correct clearance in steering joints, as indicated in section 6 “Maintenance service” Worn-out mechanical joints or bearings Replace worn-out components

Air in HSC hydraulic system Bleed air from the HSC hydraulic system by turning steering wheel with movement of guide wheels from left-most to the right-most position (stop stop-tostop position) for 2-3 times

Break of dosing pump air tightness throughout spool shank, socket casing - gerotor twin – cover

Wear of spool sealing Contact the dealer. Replacement of faulty sealing, assembly and check of operability should be is performed only by maintenance department in accordance with manufacturer’s instruction 1) Loose dosing-pump cover bolt Tighten bolts with torque of 30 to 35 N·m Damaged sealing disks under dosing-pump cover bolt heads Replace sealing disks

Different minimum minimal radius of tractor turning to the left and to the right

Faulty toe-in of front wheels Adjust toe-in of front wheels according to section 6

Partial steering angle of steerable wheels

Insufficient pressure in HSC hydraulic system due to the following reasons: - faulty adjustment of dosing pump pressure relief valve (low pressure) - Faulty feed pump Contact the dealer. Adjust pressure relief valve for the required pressure1). Operation is performed only by maintenance department. Contact the dealer. Increased FDA reducing gear steering torque Make repair of FDA

High pressure in HSC hydraulic system due to the following reasons:

- Incorrect high-pressure hose connection

- locking of back-pressure valve or dosing pump pressure relief valve (perhaps due to dirt accumulation) Connection should be carried out in strict correspondence to operation manual

Contact the dealer. Rinse of dosing-pump components is required. Assembly and check of operability should be is performed only by maintenance department in accordance with manufacturer’s instruction 1)

Breakdown of feed pump

__________________________________________________________________________________________________ 1) Considering baffling complexity and responsibility of dosing pump from the point of view of steering system safety, its assembly and disassembly can be carried out only by servicing personnel of manufacturing company (or other authorized maintenance department), properly