Komatsu 830E-AC Shop Manual page 780

Trouble
No pump output
Low pump output
Unresponsive or slug-
gish control
Loss of pressure
Excessive or high peak
pressure
L10-12
TROUBLESHOOTING CHART
(Steering Pump)
Possible Cause
Trapped air inside steering pump.
Broken pump drive shaft.
Excessive circuit leakage.
No oil to pump inlet.
Low pump pressure.
Compensator valve, seat, spring or
packing failure.
Worn or scored pistons and bores.
Maximum volume stop limiting
pump stroke.
Worn or damaged piston shoes,
swashblock or swashblock wear
plate.
Worn or grooved cylinder wear plate
and/or port plate.
Restricted inlet.
Insufficient inlet oil.
Control piston seals broken or dam-
aged.
Swashblock saddle bearings worn
or damaged.
Faulty output circuit components.
Worn piston pump.
Worn or grooved cylinder wear plate
and/or port plate: wear plate and/or
port plate separation from cylinder,
each other or valve plate.
Worn pistons, shoes or piston
bores.
Faulty output circuit components.
Hydraulic Check-out Procedure
Suggested Corrective Action
Bleed trapped air. Refer to "Pressure Check
And Adjustment Procedure", this Section.
Replace pump drive shaft.
Check for loose fittings, broken or cracked
tubes.
Check hydraulic tank oil level. Make sure
shut-off valve is open.
Check or adjust compensator pressure set-
ting.
Repair or replace compensator.
Repair or replace pistons or pump housings.
Turn volume stop screw counterclockwise.
Tighten jam nut.
Repair or replace defective parts.
Repair or replace defective parts.
Clear restriction. Make sure suction line
shut-off valve is open. Clean suction
strainer.
Check for proper hydraulic tank oil level and
make sure suction line shut-off valve is
open.
Repair or replace broken parts.
Repair or replace broken parts.
Repair or replace relief valve or pressure
compensator valve.
Repair or replace worn parts.
Repair or replace worn parts.
Repair or replace worn parts.
Repair or replace relief valve or pressure
compensator valve.
L10028