6-47
2. TROUBLESHOOTING
Diagnose malfunction charts are arranged from most probable and simplest to verify, to least
likely, more difficult to verify. Remember the following steps when troubleshooting a problem :
Step 1. Operational check out procedure (see section 1)
Step 2. Operational checks (see group 2)
Step 3. Troubleshooting
Step 4. Tests and adjustments (see group 3)
※
Problem
Cause
Remedy
Noisy hydraulic pump
Low oil supply or wrong viscosity.
Plugged or pinched suction line.
Air in oil.
Plugged suction strainer.
Loose or missing hydraulic line clamps.
Hydraulic lines in contract with frame.
Worn or damaged pump.
Fill reservoir with recommended oil.
Clean or replace line.
Check for foamy oil. Tighten
connections.
Replace O-rings and or lines.
Inspect and clean strainer in reservoir.
Tighten or replace clamps.
Inspect and repair.
Do hydraulic pump performance check
in group 2. Do hydraulic pump flow test
in group 3.
No or Slow hydraulic
functions
Failed or worn hydrualic pump.
Cold oil.
Slow engine speed.
Suction line air leak.
Low oil supply.
Wrong oil viscosity.
Oil leaking past cylinders or control
valve.
Blocked or damaged line.
Faulty pilot control valve (RCV).
Binding loader control valve (MCV)
spool.
Faulty steering valve (EHPS).
Do performance check.
Warm oil up.
Adjust engine speed.
Check high idle speed.
Check for foamy oil.
Add recommended oil.
Use recommended oil.
Check cylinder drift in group 2.
Inspect lines.
Do pilot control valve (RCV) pressure
test in group 3.
Inspect valve.
Check priority valve, orifice of steering
valve (EHPS) specification.
Summary of Contents for HL955
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