TM-9-2320-260-34-1

TRUCK, 5-TON, 6X6, M809 SERIES (DIESEL)

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE; VOLUME 1 OF 2

JULY 1994
TM-9-2320-260-34-1

  TM-9-2320-260-34-1 - Page 41 of 657

TM 9-2320-260-34-1
Table 2-1. Mechanical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
72. BOOM FAILS TO RAISE OR RAISES AND LOWERS SLUGGISHLY
Step 1. Perform pressure check (TM 9-2320-260-20). Tee into hydraulic lift line crossover and tee in
test gage.
a. Proceed to step 2 if pressure is sufficient.
b. Proceed to malfunction 68, steps 2 and 3 if pressure is low or erratic.
WARNlN G
All personnel must stand clear during lifting operations.
A swinging or shifting load may cause injury to personnel.
Step 2. Determine if one or both boom elevating cylinders are defective by disconnecting boom
elevating cylinders from boom (para. 16-14) and raising boom with suitable lifting device.
Operate control valve (TM 9-2320-260-10) and determine if one or both boom elevating
cylinders are defective.
Replace boom elevating cylinder(s) if defective (para. 16-14).
END OF TESTING!
TRACTOR WRECKER (M819)
NOTE
Tractor wrecker crane hydraulic systems are tested the same as
medium wrecker, except boom swing system.
73. CRANE BOOM FAILS TO SWING (OTHER HYDRAULIC SYSTEMS OPERATE SATISFACTORILY)
Step 1.
Step 2.
Step 3.
Determine if problem is in hydraulic or mechanical system. Attempt to rotate boom and
boom support with hydraulic pump turned off.
a. Proceed to step 2 if boom rotates easily and smoothly.
b. Proceed to step 3 if boom does not rotate easily or smoothly.
Tee into swing motor hydraulic control line and connect test gage. Operate swing control
valve.
a. Replace swing hydraulic motor if pressure is steady and sufficient (para. 16-30).
b. Perform malfunction 68, steps 2 and 3 if pressure is low or erratic.
Check crane base, bearings, and pivot post for mechanical binding or obstruction.
Repair base, bearings, or pivot post if binding or damaged (para. 16-34).
END OF TESTING!
HYDRAULIC LIFTGATE (M820A2)
74. LIFTGATE WILL NOT OPEN OR CLOSE
Step 1.
Step 2.
Step 3.
Check pump pressure (TM 9-2320-260-20). Tee into pump output hydraulic line and connect
test gage. Operate liftgate controls.
Replace auxiliary pump if output pressure is low (para. 15-56).
Check operation of control valve.
Clean or replace control valve if defective (para. 15-58).
Check if grasp locks are sticking or linkage is binding.
Replace control linkage or locks if defective (para. 15-55).
END OF TESTING!
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