9-9
6. HYDRAULIC SYSTEM
6. HYDRAULIC SYSTEM
Trouble symptom
1. Large fork lowering speed.
2. Large spontaneous tilt of
mast.
·
Seal inside control valve defective.
·
Oil leaks from joint or hose.
·
Seal inside cylinder defective.
·
Tilting backward : Check valve defec-
tive.
·
Tilting forward : Tilt lock valve defect-
ive.
·
Oil leaks from joint or hose.
·
Seal inside cylinder defective.
·
Clean or replace.
·
Clean or replace.
·
Replace.
·
Replace seal.
·
Replace spool or valve body.
·
Replace.
·
Replace packing.
Probable cause
Remedy
3. Slow fork lifting or slow
mast tilting.
4. Hydraulic system makes
abnormal sounds.
5. Control valve lever is locked
6. High oil temperature.
·
Lack of hydruilc oil.
·
Hydrauic oil mixed with air.
·
Oil leaks from joint or hose.
·
Excessive restriction of oil flow on
pump suction side.
·
Relief valve fails to keep specified
pressure.
·
Poor sealing inside cylinder.
·
High hydraulic oil viscosity.
·
Mast fails to move smoothly.
·
Oil leaks from lift control valve spool.
·
Oil leaks from tilt control valve spool.
·
Excessive restriction of oil flow pump
suction side.
·
Gear or bearing in hydraulic pump
defective.
·
Foreign matter jammed between sp-
ool and valve body.
·
Valve body defective.
·
Lack of hydraulic oil.
·
High hydraulic oil viscosity.
·
Oil filter clogged.
·
Add oil.
·
Bleed air.
·
Replace.
·
Clean filter.
·
Adjust relief valve.
·
Replace packing.
·
Change to SAE10W, class CF engine
oil.
·
Adjust roll to rail clearance.
·
Replace spool or valve body.
·
Replace spool or valve body.
·
Clean filter.
·
Replace gear or bearing.
·
Clean.
·
Tighten body mounting bolts uniform-
ly.
·
Add oil.
·
Change to SAE10W, class CF engine
oil.
·
Clean filter.