TM 10-3930-641-34-1
HYDRAULIC SYSTEM TROUBLESHOOTING
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
HYDRAULIC SYSTEM
1. HYDRAULIC SYSTEM WILL NOT LIFT LOAD
Step 1. Inspect for air leaks on low pressure side of hydraulic oil pump (suction side).
Repair. (See page 7-13.)
Step 2. Test relief valve for proper operation. (See TM 10-3930-641-20.)
Adjust relief valve. (See TM 10-3930-641-20.)
Step 3. Inspect hydraulic pump for worn components.
a.
Repair/replace. (See page 7-5.) Drain and flush system (see LO 10-3930-641-12.)
b.
Find and correct the cause of pump failure (cavitation, aeration, dirty oil).
Step 4. Inspect hydraulic pump drive for damage.
Repair/replace as necessary.-(See page 7-5.)
Step 5. Inspect mast sliding blocks, rollers, and chains for proper lubrication.
Lubricate components as necessary. (See LO 10-3930-641-12.)
Step 6. Inspect carriage rollers and bearings for wear.
Replace/repair as necessary. (See page 7-94.)
Step 7. Check adjustment of mast with other lifting components. (See page 7-76.)
Adjust mast as necessary. (See page 7-76.)
2. CARRIAGE WILL NOT LOWER CORRECTLY
Step 1. Check for restrictions in lift line.
Clean/replace. (See TM 10-3930-641-20.)
Step 2. Check lift cylinder packing nut for tightness.
Loosen packing nut.
Step 3. Inspect lift cylinder flow control valve.
Clean/repair as necessary. (See page 7-44.)
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