Troubleshooting (Continued)
Problem
Cause
Correction
Unable to push valve
Bent spool
Replace with new spool section.
spool in
Foreign particles
Clean system and valve.
Misalignment of control handle
Check linkage for binding condition.
linkage
Spring centered spools
Paint on valve spool; sticking
Clean valve spool. Binding is usually
do not return to neutral
valve spool or scored valve
caused from an over tightened plug,
spool
mounting bolt, fitting in valve body or
tie rod bolt. If a plug or fitting in the
valve body is leaking, do not overtighten
in an effort to stop leak. This will distort
body casting and cause spools to bind.
Instead, the plug and fitting should be
removed from valve body and be
reconnected, using a new O-ring. Do
not apply excessive pressure on
mounting bolts. The rods for CBH70,
CBH80 should be torqued to 14 ft/lbs for
5/16” nuts and 33 ft/lbs for 3/8”nuts.
Never force spool.
Oil leakage past spool seal into
Remove cap. If it contains oil replace spool
spool cap
seal O-rings. Check O-ring retainer to be
sure it is flat. If it has been “belled” check
for restriction from outlet to reservoir of
valve which would cause excessive back
pressure. If supply and return lines are
reversed, pressure on low pressure / return
side of valve will cause problem.
Make sure hoses are connected correctly
at bulkhead connection on backhoe.
Broken return springs
Replace springs.
Bent spool
Replace with new spool section.
Foreign particles
Clean system and valve.
Misalignment of control handle
Check linkage for binding condition.
linkage
24
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