SECTION 3 – TROUBLESHOOTING
3120933 Rev. 0
USTC
3-9
Add oil.
Remove line and clear
obstruction or replace line.
Repair or replace pump.
Repair or replace control cable.
Check pressure delivery from
control valve and repair or
replace valve.
Repair or replace motor.
Repair or replace swing brake.
Repair or replace drive hub.
Adjust or replace relief valve.
Remove line and clear
obstruction or replace line.
Check pressure delivery from
control valve and repair or
replace valve.
Remove obstruction and check
for damage. Repair as
necessary.
Replace counterbalance valve.
Add oil.
Remove line and clear
obstruction or replace line.
Repair or replace pump.
Replace pinion gear or swing
bearing.
Repair or replace motor.
Repair or replace swing brake.
Replace counterbalance valve.
Hydraulic oil level low.
Restricted or broken supply line.
Malfunctioning hydraulic pump
section.
Control cable broken, kinked or
disconnected.
Worn control valve spool.
Malfunctioning swing motor.
Malfunctioning swing brake.
Malfunctioning drive hub.
Relief valve in control valve inlet
set too low.
Restricted or broken supply line.
Worn control valve spool.
Foreign object wedged in swing
gear teeth.
Malfunctioning counterbalance
valve.
Hydraulic oil level low.
Restricted or broken supply line.
Malfunctioning hydraulic pump.
Worn or broken teeth on drive
hub pinion or swing bearing
gears.
Malfunctioning swing motor.
Malfunctioning swing brake.
Malfunctioning counterbalance
valve.
No turntable swing in either
direction.
TROUBLE
PROBABLE CAUSE
REMEDY
Table 3-4. Hydraulic Components (continued)
Turntable swings in only one
direction.
Swing motion erratic.