HYDRAULIC SYSTEM TROUBLESHOOTING (CONT)
TEST OR INSPECTION
2. CARRIAGE WILL NOT LOWER CORRECTLY (CONT)
Step 4. Inspect control valve lift spool.
Clean/replace as necessary. (See page 7-44.)
Step 5. Inspect mast sliding blocks, rollers and bearings for proper lubrication. (See LO 10-3930-641-12.)
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 mas t with other lifting components. (See page 7-76.)
Adjust mast as necessary. (See page 7-76.)
3. MAST TILTS OR LIFTS TOO SLOWLY
Step 1. Inspect for air leaks on low pressure side of hydraulic 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.
Repair/replace as necessary. (See page 7-5.)
Find and correct the cause of the pump failure. (Dirty oil, cavitation, aeration).
Step 4. Check engine performance.
Step 5. Inspect tilt cylinder rods for damage.
Replace as necessary. (See page 7-54.)
Step 6. Check lift or tilt cylinder packing nuts for tightness.
Loosen packing nuts. (See page 7-54 or 7-66.)