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Troubleshooting (Continued)
Problem Cause Correction
Leaky valve Paint on valve spool; sticking (cont.)
valve spool or scored valve spool 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.
Ball in anti-cavitation check Clean anti-cavitation valve carefully, being
valve is stuck or not seating sure that checks move freely and seat
properly. properly, or replace cartridge.
Sticky valve spool Paint on valve spool; sticking Clean valve spool. Binding is usually
spool in valve spool or scored valve caused from an overtightened 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 exces-
sive 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.
Bent spool Replace with new spool section.
Foreign particles Clean system and valve.
Misalignment of control handle Check linkage for binding condition
linkage
Unable to push valve Paint on valve spool; sticking Clean valve spool. Binding is usually
spool in valve spool or scored valve caused from an overtightened 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 exces-
sive 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.
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