GROVE
Published 1-20-2017, Control# 483-02
4-7
CD5515-2/YB5515-2 SERVICE MANUAL
HYDRAULIC SYSTEM
4
Table 4-5
Main Hoist Circuit Troubleshooting
Table 4-6
Swing Circuit Troubleshooting
Problem
Possible Cause
Remedy
Hoist will not lift maximum (rated) load,
considerable reduction in line speed.
Faulty load sense relief valve.
Replace the relief valve.
Dirt in load sense relief valve, keeping
the valve off the valve seat.
Remove and clean the relief valve. See
Main Relief and Port Relief Valves.
Not enough oil from the pump.
Check hoses and lines for restrictions
to or from pump.
Improper primary pump pressure.
Check and adjust pressures.
Malfunction or damage to hoist
components.
Check and overhaul the hoist, if
necessary. See Chapter 11, 1. Check
for binding or damaged sheaves.
Internal leakage in the hoist motor.
Replace the hoist motor.
Raise speed is slower than lowering
speed.
Restriction in hose to control valve.
Check and repair.
Faulty counterbalance valve.
Replace the counterbalance valve.
Motor will not hold the load when the
control lever is in neutral — load drops
rapidly.
Overload condition.
Decrease the load.
Faulty counterbalance valve.
Replace the counterbalance valve.
Motor will not hold the load when the
control lever is in neutral — load drifts
down slowly.
Overload condition.
Decrease the load.
Faulty counterbalance valve.
Replace the counterbalance valve.
Hoist does not move.
Restriction in holding valve cartridge.
Clean or replace the holding valve
cartridge.
Brake not releasing.
Check condition of the brake. Repair
as necessary.
Low pilot pressure.
Check and adjust.
Hook block lowers, but will not raise.
Malfunction in anti-double blocking
electrical system.
Bad cartridge in anti-double blocking
solenoid valve.
Faulty controller.
Faulty controller.
Repair or replace.
Restriction in pilot control line to control
valve.
Locate and correct.
Problem
Possible Cause
Remedy
Mast will not rotate when the swing
control is actuated.
Damaged or broken motor shaft.
Repair or replace the swing motor.
Damaged or broken gearbox shaft or
gear.
Overhaul or replace the gearbox. See
Chapter 11, 1.
Faulty pump.
Overhaul or replace the pump.
Leakage in hydraulic swivel.
Replace seals in the swivel.
Main relief valve malfunction.
Check main relief pressure.
Dirt or restriction in swing relief.
Clean the relief valve.
Low pilot pressure.
Check and adjust.
Faulty controller.
Repair or replace.
Difficult or slow swing.
Friction or restriction in mast bearing.
See Chapter 11, 1.
Faulty swing motor or gearbox.
Repair or replace.
Reference Only
