Thomas 85 - Hydraulic System; Final Drive Transmission

42
Problem Cause Remedy
Replenish with 10W30
API SE/CD oil. Check
for hose or fitting leak.
Inspect and replace
damaged parts. Check
for misalignment
between engine and
pumps.
Inspect coupling for
sheared splines. Also
check pump shaft
bearings.
Inspect and repair
Replenish with 10W30
API SE/CD oil.
Inspect and adjust
Disengage
Check pressure and
adjust
Replenish with 10W30
API SE/CD oil.
Check for leak between
reservoir and pump.
Bleed system by
extending and
retracting lift cylinders
several times.
Inspect and repair or
replace
Replenish with 10W30
API SE/CD oil.
Inspect and adjust
Disengage
Check RPM and reset
Replace
4 MAINTENANCE
4. 11C Hydraulic System
Reservoir low on
oil.
Universal joint
between engine and
pump failure
Spline coupling
failure between front
and rear hydrostatic
pump.
Hydraulic gear
pump not
functioning
Reservoir low on
oil.
Foot pedal linkage
disconnected or
binding
Auxiliary hydraulics
engaged
Relief valve failure
in control valve
Reservoir low on
oil.
Air in hydraulic
system
Anti-cavitation
check valve not
functioning
Reservoir low on oil
Control linkage
binding
Auxiliary foot pedal
engaged
Engine RPM too
slow
Pilot check valve
spring broken
Loss of hydraulic
power (no flow
from gear pump)
Loss of hydraulic
power (flow from
gear pump)
Hydraulic action
jerky
Boom raises slowly
at full engine RPM
Problem Cause Remedy
Check pressure flow
and repair or replace
pump as necessary
Check pump flow and
repair or replace pump
as necessary
Install new piston seal
kits
Check for leak and
correct
Check for sticking foot
pedal linkage Check
for broken or stuck
return spring on valve
spool.
Install new piston seal
kits
Replenish with 10W30
API SE/CD oil
Disengage
Check RPM and adjust
Replace
Pressure relief valve
in control valve
faulty
Internal leakage in
pump due to wear
Oil bypassing one or
both lift cylinder
piston seals
External leak
between or at
control valve and
cylinders
Control valve spool
not centering
Oil leaking by one
or both cylinder
piston seals
Reservoir low on
oil.
Auxiliary hydraulics
engaged
Engine RPM too
slow
Inoperable
temperature sensor
Boom raises slowly
at full engine RPM
Lift or tilt cylinders
will not support a
load
Hydraulic oil
overheating
Problem Cause Remedy
Check and bring oil to
the proper level. Use
10W30 SE/CC engine
oil
Pre-load axle bearings
removing all end play
Inspect and adjust or
replace damaged parts.
Replace parts
No lubricating oil
Axles have too
much end play
Parking brake
damaged or out of
adjustment
Chain loose
Final drive
transmission noisy
4. 11D Final Drive Transmission