TM 9-2320-260-34-1
Table 2-1. Mechanical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 2. Check hydraulic lock operation. Operate controls to raise dump body (TM 9-2320-260-10).
Observe hydraulic lock operation.
a. If hydraulic lock will not release, manually open hydraulic lock and secure in open
position. Operate dump body to raise. Replace hydraulic cylinder or lock assembly if
dump body raises (para. 15-15 or 15-16).
b. Check control valve and relay control box if dump body will not raise with hydraulic lock
open (paras. 15-19 and 15-20).
Step 3. Check control box operation. Move main control lever in cab and observe control box levers
movement.
If control box lever will not operate control valve lever through full travel, check control box
lever for defective woodruff key(s). Replace woodruff key(s) if defective (para. 15-19).
WARNING
Bleed hydraulic pressure before cracking hydraulic lines. Failure
to do so may result in damage to equipment and injury to
personnel.
Overhead lifting device capacity must exceed dump body weight.
A swinging, shifting, or falling load may cause injury to
personnel.
Step 4. Check hydraulic system for leaks.
a. Tighten or replace hydraulic hose fittings if leaking (para. 15-20).
b. Replace hydraulic hoses if leaking (para. 15-20).
Step 5. Attach overhead lifting device to dump body and secure dump body hydraulic lock. Raise
dump body with lifting device until dump body is in fully raised position. Secure dump body
with safety braces (TM 9-2320-260-10).
Step 6. Remove all hydraulic hose ends from hydraulic pump only. Install tee fitting into one of
three open ports of hydraulic pump and plug two ports in hydraulic pump. Install high
pressure gage into tee. Remove one hydraulic hose from lock cylinder and adapt ends to
connect to tee and other open port on pump.
Step 7. Operate dump body with main control lever (set in D position) (TM 9-2320-260-10). Maintain
engine speed at 1000 rpm for 10 seconds and observe pressure gage.
a. Remove hoist pump adapter and clean or replace stuck or broken springs, relief valve,
or plunger if pressure reading is uneven or zero (para. 15-17).
b. Replace hoist pump adapter if defective (para. 15-17).
Step 8. Replace hoist pump if pressure reading is uneven or zero (para. 15-17).
Step 9. Replace control valve if pressure readings decrease slowly (para. 15-19).
Step 10. Check hoist cylinders operation. Remove safety braces and lower dump body until seated on
subframe. Remove lifting device. Operate dump body to raised position
(TM 9-2320-260-10).
a. Check hoist safety latch position if dump body will not raise. Replace hoist safety latch if
not in release position (para. 15-16).
b. Replace hoist cylinders if dump body remains inoperative (para. 15-15).
END OF TESTING!
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