15 - 3
Fault Probable Cause Action
5 A spool is sticking. Oil temperature abnormally high. Check for correct fluid, see Lubricants
and Capacities. Check oil cooler and
grille for blockage.
The hydraulic fluid is dirty. Clean the tank strainer. If strainer badly
clogged, drain and flush hydraulic system
Fill with clean hydraulic fluid.
The service pipe connection Check tightening torque.
is over tightened.
The valve housing was twisted Loosen retaining bolts and tighten to
during installation. correct torque figures.
Pressure too high. Check system pressure.
A control linkage is bent Disconnect the linkage. Repair the
linkage if possible, or fit a new one
A spool is bent Dismantle the control valve. Renew spool
as necessary.
A return spring is broken. Renew as necessary.
A return spring or cap is out of Remove the cap, check that the spring is
alignment. in the correct position. Refit cap and
torque tighten bolts
Temperature distribution within Warm the entire system up before
control valve not uniform. using service.
6 Leaking Oil Seal (Control Valves) Paint or dirt on the seal face. Remove the seal and clean.
The back pressure in the valve Check circuit pressures, adjust if
circuit is excessively high. possible. Otherwise investigate
thoroughly.
Spool damaged. Dismantle. Inspect all parts. Renovate or
renew as necessary.
The seal is not secured. Clean the seal and tighten the retaining
bolts to the correct torque.
The seal is cut or damaged. Fit a new seal.
7 Ram creep. Associated ram or pipe lines from Check and rectify as required.
ram leaking.
Check valve malfunctioning Test check valve, rectify as required.
(if fitted, e.g. stabiliser circuit)
Associated valve section spools Rectify, check for contamination.
leaking.
Associated ARV leaking Rectify, check for contamination .
Note: Refer also to Service Procedures, Ram Creep Tests - All Services
Section E
Hydraulics
9803/3280
Section E
15 - 3
Issue 1
Fault Finding
To Next Page
Loading...
Need help?
General
