TROUBLESHOOTING GUIDE
5-7
TABLE OF CONTENTS
Hydraulic System
Most hydraulic system failures follow the same pattern: a
gradual or sudden loss of pressure or flow with a
resulting loss of cylinder or motor power. Any one of the
system’s components may be at fault. By following
step-by-step procedures, the trouble can be located in a
short time.
PROBLEM PROBABLE CAUSE SOLUTION
SEMITRAILER LOCKED IN TILTED
POSITION
Velocity fuse activated Raise the trailer slightly (to reset the
velocity fuse), then lower the trailer
slowly.
SYSTEM INOPERATIVE Not enough oil in system Fill, check for leaks.
Wrong oil in system Change oil, see specifications (See
Table 4-1 on page 4-3.)
Filter dirty or clogged Drain oil and replace filter.
Hydraulic lines dirty or collapsed Clean or replace as necessary.
Air leaks in pump suction line Repair or replace as necessary.
Worn or dirty pump Clean, repair or replace. Check for
contaminated oil. Drain and flush.
Badly worn components Examine for internal leakage. Replace
faulty components. Check for cause
of wear.
Leakage Check all components, and relief valve
for proper settings.
Excessive load Check unit specifications for load limit
(See “Standard Specifications”
on page 2-1.)
Slipping or broken pump drive Repair or replace couplings. Check for
alignment.
SYSTEM OPERATES ERRATICALLY Air in the system Check suction side of system for leaks.
Repair leaks.
Cold oil Allow ample warm-up time. Use proper
weight oil for operating temperature.
Dirty or damaged components Clean or repair as needed.
Restriction in filters or lines Clean and/or replace filter or lines.
Not enough oil in system Fill and check for leaks.
SYSTEM OPERATES SLOWLY Oil viscosity too high, or “cold oil” Allow oil to warm up before operating.
Low pump drive speed Increase engine speed (check pump
owner’s manual for specifications.)
Low oil level Check reservoir and add oil as
necessary.
Air in system Check suction side for leaks. Repair
leaks.
Badly worn pump, valves, cylinders, etc. Repair or replace faulty component(s)
as necessary.
Restrictions in lines or filter Clean and/or replace filter or lines.
Improper adjustments Check orifices, relief valves, etc. Adjust
as necessary.
Oil leaks Tighten fittings. Replace seals, gaskets
and damaged lines.
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