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Section 6: Troubleshooting
7/14/08
BH3512 Backhoes 340-131M
Land Pride
Table of Contents
Problem Cause Solution
Sticking plungers in
Hydraulic Valve
Excessively high oil temperature. Eliminate restrictions in pipe lines and filtering system.
Dirt in oil. Change oil-clean system.
Pipe fittings too tight. Check torque.
Valve warped from mounting. Loosen valve and check.
Excessively high pressure in valve Check with gauge on inlet and cylinder lines.
Handle or linkage binding. Free up linkage.
Plunger bent. Replace valve or section.
Return spring damaged. Replace faulty parts.
Spring or detent cap binding. Loosen cap, re-center and re-tighten.
Valve not at thermal equilibrium. Let system warm up.
Leaking Seals in
Hydraulic Valve
Paint on or under seal. Remove and clean.
Excessive back pressure. Open or enlarge line to reservoir.
Dirt under seal. Remove and clean.
Scored plunger. Replace valve or section.
Loose seal plates. Clean and tighten.
Cut or scored seal. Replace faulty parts.
Unable to move plunger
in Hydraulic Valve
Dirt in valve. Clean and flush out.
Plunger cap full of oil. Replace seals.
Bind in linkage. Free up linkage.
Blown or leaking O-ring
seals between valve sec-
tions in Hydraulic Valve
Improperly connected. Replace O-Ring seals. Make sure all connections are as
shown in the assembly section of this manual.
Return line was replaced with high
pressure hose.
Replace O-Ring seals. Remove high pressure hose and
replace it with correct low pressure hose.
Valve used in power beyond applica-
tion without installation of power
beyond sleeve.
Replace O-Ring seals. Install power beyond sleeve as
shown in assembly section of this manual.
Can’t get pressure in
Relief Valve
Poppet stuck open or dirt under
seat.
Check for foreign matter between poppets and their mat-
ing members. Members must slide freely.
Erratic pressure in Relief
Valve
Pilot poppet seat damaged. Poppet
sticking in relief valve housing.
Remove and clean dirt out. If parts are damaged, replace
complete relief valve.
Pressure setting not
correct in Relief Valve
Wear due to dirt. Locknut and
adjustment screw loose.
See “How to Set Pressure”.
Check seats for scratches, nicks or other marks. Replace
valve if damaged.
Relief Valve leaks
Damaged seats, worn O-Rings,
parts sticking due to dirt.
Replace worn or damaged O-Rings and back up rings.
Inspect for free movement of components, check seat for
scratches, nicks or other marks. Replace complete relief if
metal parts are damaged.
Backhoe does not
operate
Low oil supply. Add oil.
Hoses not properly connected. Check hose connections.
Worn or damaged pump. Replace or repair pump.
Broken line. Check for leaks. Replace line.
Section 6: Troubleshooting