Clark GEX20 - Troubleshooting

Group 34, Uprights
SM 765, Nov ’06 Troubleshooting • 34-2-1
The visual inspection and the operational checks pre-
sented in Section 3 should be used to determine problems
with the upright. Possible problems, causes, and remedies
are listed below.
Other troubleshooting information about the hydraulic cir-
cuit and components appears in the troubleshooting Sec-
tions of Groups 29 and 30. Use these other
troubleshooting Sections for more detailed problem isola-
tion with Upright hydraulic functions.
WARNING
!
The procedures for troubleshooting uprights,
carriages, and forks involve movement of the
components. Failure to follow these warnings
can result in serious injury.
Make sure overhead clearances are adequate
before raising the upright to full lift height.
Do not walk or stand under raised forks.
Block carriage and upright whenever making
checks with the upright elevated.
Keep clear of load and carriage when making
any check or adjustment.
Keep your arms and fingers away from mov-
ing parts of the upright.
Do not reach through open areas of the
upright.
Upright noise
• Bent or broken components; inspect upright thor-
oughly and repair or replace components as
required.
• Damaged upright roller; check condition of rollers
and replace defective rollers.
• Roller scuffing rails; clean and lubricate rails.
• Roller (carriage or upright) shimming needs
adjustment; check and adjust as required.
• Fit between roller edge and rail flange excessively
loose in rails; replace with oversized, “Select-Fit”
rollers. See “Upright Roller Clearance Check and
Shim Adjustment.”
• Dry lift chain; lubricate chain.
• Dry hose sheave or rollers; check condition of all
sheaves and rollers and lubricate as necessary.
• Damaged chain sheaves; check condition of chain
sheaves and repair or replace.
• Excessive fork hanger or carriage fork bar wear;
inspect and replace as necessary.
• Seals dry; lubricate rod.
• Seals dry - all primary cylinders; remove gland and
add 100 ml (3.4 oz) of hydraulic oil to rod side of
piston, see “Cylinder Removal, Shimming, Over-
haul, and Replacement.”
No lift, tilt, or auxiliary function
• Hydraulic fluid level low; check level and fill.
• Broken hoses or fittings; check and repair.
• Damaged or blocked sump strainer; check and
clean.
• Hydraulic pump defective; see Group 29 for pump
troubleshooting.
• Defective main hydraulic control valve; see Group
30 for valve troubleshooting.
• Defective upright load-lowering flow valve; disas-
semble valve, check and clean or replace.
No lift function but tilt operates
• Broken hoses or fittings; check and repair.
• Cylinder is damaged; inspect and repair.
• Main hydraulic control valve, lift section defective;
see Group 30 for valve troubleshooting and ser-
vice information.
• Upright load-lowering flow valve damaged; disas-
semble valve, check and clean or replace.
Section 2
Troubleshooting