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Troubleshooting
Symptom
Possible Cause
Forks will not lift
1. Hydraulic oil low.
to max height.
Forks do not lift. 1. Hydraulic oil low/contaminated.
2. Too much hydraulic oil in pump assembly/air
in hydraulic system.
3. Pump valve nut too tight.
Forks do not
1. Lifting components jammed with debris.
lower.
2. Pump valve nut too loose.
3. Lifting components bent/damaged.
Forks lower by
1. Impurities in relief valve/hydraulic oil.
themselves.
2. Relief valve faulty/damaged.
3. Seals worn/damaged.
Forks lower too
1. Pump valve nut misadjusted.
slowly.
Forks lower too
1. Pump valve nut misadjusted.
quickly.
Oil leaks.
1. Relief valve damaged.
2. Oil fill plug gasket damaged.
3. Seals worn/damaged.
4. Cracked/worn/damaged parts.
Adjusting Pump Valve Nut
Pump valve nut on the back of the hydraulic cyl-
inder controls how open the pump valve is (see
Figure 9). If the nut is too loose, the forks will not
lower correctly, and if too tight, they won't lift.
Pump Valve Nut
Figure 9. Pump valve nut location.
Changing Hydraulic Oil
Hydraulic oil in the cylinder may need to be added
periodically after prolonged use or if it leaks
noticeably. We recommend ISO 32 or 46 grade
hydraulic oil.
To add hydraulic oil:
1.
Lower forks completely.
-4-
Possible Solution
1. Fill pump assembly with hydraulic oil.
1. Fill pump assembly with hydraulic oil. If necessary,
drain old/contaminated oil and replace.
2. Pump off extra hydraulic oil/air.
3. Loosen pump valve nut.
1. Inspect mechanism, clear debris.
2. Tighten pump valve nut.
3. Inspect/replace damaged lifting components.
1. Clean relief valve/change hydraulic oil.
2. Inspect/replace.
3. Inspect/replace.
1. Tighten pump valve nut.
1. Loosen pump valve nut.
1. Inspect/replace.
2. Inspect/replace.
3. Inspect/replace.
4. Inspect/replace.
2.
Remove both hydraulic cylinder plugs (see
Figure 10) and allow oil to drain completely.
Figure 10. Hydraulic cylinder plug locations.
3.
Replace lower plug and add replacement oil
to upper fill hole until level reaches bottom of
hole.
4.
Without replacing fill plug, pump one lift
handle 10–15 times to expel any trapped air.
5.
Replace fill plug and clean up any hydraulic
oil residue. Old oil can be stored in a sealable
metal or thick plastic container and recycled
at a recycling center near you.
Model T31643 (Mfd. 9/19)
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