Table 3-2 Troubleshooting

Table 3-2 Troubleshooting - Continued

Corrective action

Probable cause

Malfunction

b. Drain crankcase and fill with proper grade

b. Improper grade of oil.

of oil for operating temperature (LO

10-3930-621-12).

c. Perform compression test (para 3-27).

c. Faulty rings or valves.

d. Clean breather (para 3-26) or replace vent

d. Crankcase ventilation system clogged.

valve (para 3-26).

a. Drain to correct level.

a. Crankcase oil level too high.

9. Excessive exhaust smoke.

b. Replace gasket (para 3-24).

b. Cylinder head gasket leaking.

c. Adjust carburetor (para 3-29).

c. Carburetor out of adjustment.

a. Normal condition; no action required.

a. Battery fully charged.

10. Charging rate on ammeter lower than

b. Adjust belt tension (para 3-12).

b. Drive belt loose.

normal.

c. Adjust or replace regulator (para 3-42).

c. Improperly adjusted or defective

regulator.

d. Replace alternator (para 3-41).

d. Alternator defective.

a. Normal condition; no action required.

a. Battery charge low.

11. Charging rate on ammeter higher

b. Adjust or replace regulator (para 342).

b. improperly adjusted regulator or

than normal.

defective regulator.,

a. Replace lamp (para 349).

a. Defective lamp.

12. Lights do not function.

b. Check circuit for short in lights or wiring.

b. Blown fuse.

Replace fuse.

c. Replace switch (para 3-48).

c. Defective light switch.

a. Replace fuse.

a. Blown fuse.

13. Horn does not sound.

b. Replace horn button or parts.

b. Defective horn button.

c. Tighten connections or replace relay

c. Loose wiring or defective relay.

(para 349).

d. Replace horn (para 3-49).

d. Defective horn.

a. Adjust pedal free travel (para 3-62).

a. Improperly adjusted pedal or linkage.

14. Brakes drag.

b. Replace spring (para 3-62).

b. Weak or broken return spring.

c. Replace cylinder (para 3-63).

c. Wheel cylinder defective.

d. Adjust bearings (para 3-67).

d. Wheel bearings loose.

a. Bleed system (para 3-63).

a. Air in system.

15. Brake pedal soft or spongy when

b. Fill master cylinder (para 3-63).

depressed.

b. Inadequate oil supply.

c. Brake linings not fitted properly.

c. Replace brake shoes (para 3-64).

a. Improperly adjusted pedal or linkage.

a. Adjust pedal free travel (para 3-62).

16. Brake pedal is hard to depress.

b. Replace brake shoes (para 3-64).

b. Brake lining glared.

a. Pump pedal several times. If pressure builds

a. Air in system.

17. Excessive pedal travel required

up to hold pedal to normal travel, bleed

to apply brakes.

brake system (para 3-63).

b. Fill master cylinder.

b. Inadequate oil supply.

a. Replace brake shoes (para 3-64).

a. Fluid or grease on brake lining.

18. Truck pulls to one side when brakes

b. Replace spring (para 3-64).

are applied.

b. Brake shoe return spring defective.

c. Replace brake cylinder (para 3-65).

c. Defective wheel cylinder.

d. Adjust bearings (para 3-67).

d. Wheel bearings loose.

19. Inching mechanism not operating

a. Mechanism not adjusted properly.

a. Refer to direct and general support

properly.

maintenance personnel.

b. Refer to direct and general support

b. Defective transmission control valve.

maintenance personnel.

20. Steering mechanism not operating

a. Insufficient oil in hydraulic reservoir.

a. Fill as prescribed in LO 10-3930-621-12.

properly.

b. Tighten connections.

b. Air leaks in system.

c. Steering cylinder improperly adjusted.

c. Adjust cylinder (para 3-70).

d. Adjust tie rods (para 3-69).

d. Incorrect toe-in.

e. Defective hydraulic pump.

e. Refer to direct and general support

maintenance personnel.

f. Defective hydraulic steering valve.

f. Refer to direct and general support

maintenance personnel.

21. Truck will not lift or tilt load.

a. Load too heavy.

a. Lighten load to 4,000 pounds.

b. Insufficient oil in hydraulic reservoir.

b. Fill reservoir as prescribed in LO

10-3930-621-12.

c. Leaks in hydraulic system.

c. Inspect fittings, reservoir, and hose.

Tighten connections. Replace hose if

necessary.

d. Defective cylinder.

d. Replace cylinder (para 3-75). Refer to

direct and general support maintenance

personnel to repair cylinder.

3-9