SPECIFICATIONS

Vehicle Systems Testing And Adjusting
Problem: The mast does not tilt correctly or
moves too slowly.
Probable Hydraulic Cause:
1. There is an air leak, which lets air into the
hydraulic system on the inlet side of the hydraulic
pump.
2. The relief valve opens at low oil pressure.
3. The hydraulic pump has too much wear.
4. The internal valve of the tilt spool is stuck.
5. Control valve tilt spool has a restriction.
Probable Mechanical Cause:
1. Damage or failure of the piston rods on the tilt
cylinders.
Problem: The carriage will not lower correctly.
Probable Hydraulic Cause:
1. There are restrictions in the lift line.
2. The lift spool in the control valve has a restriction
caused by foreign material and does not operate
freely.
3. The lift cylinder flow control valve has a restriction.
4. Lift cylinders excess flow protectors have a restric-
tion.
5. Air in the hydraulic system.
Probable Mechanical Cause:
1. The mast is not in alignment with the other lifting
components and does not move freely.
2. Carriage chains need an adjustment.
3. Not enough lubricant on the part of the mast that
moves.
4. The carriage or mast rollers (bearings) are worn
and do not move (seized).
Problem: The lift or tilt cylinders do not hold their
position with the valve control levers in neutral
position.
Probable Cause:
1. The valve spools do not hold their positions
because the springs for the valve spools are weak
or broken.
2. Control valve leakage caused by worn valve
spools.
3. The check valve or flow control valves in the con-
trol valve are bad.
4. Leakage of the cylinder lines or piston seals.
5. There is foreign material in the control valve.
Hydraulic Pump
Problem: Noise in the pump.
Probable Cause:
1. The oil level is low.
2. The oil is thick (viscosity too high).
3. The pump inlet line has a restriction in it.
4. Worn parts in the pump.
5. Oil is dirty.
6. Air leaks into the inlet line.
Problem: The oil temperature is too high.
Probable Cause:
1. The oil level is low.
2. There is a restriction in an oil passage.
3. The relief valve setting is too low.
4. The oil is too thin.
5. There is air leakage in the system.
6. The pump has too much wear.
7. The system operates at too high a pressure.
a. Relief valve setting too high.
b. Attachment components cause a restriction dur-
ing movement.
c. Restrictions in flow control valve, check valve
and in oil lines.
Problem: Leakage at the pump shaft seal.
Probable Cause:
1. The shaft seal is worn.
2. The inner parts of the pump body are worn.
3. Operation with too low oil level in tank causes
suction on the seal.
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