HYDRAULIC PUMP TROUBLESHOOTING

TM 10-3930-638-24&P

3-22. HYDRAULIC PUMP TROUBLESHOOTING (cont)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1. VEHICLE WILL NOT TURN WHEN STEERING WHEEL IS TURNED (cont)

Step 2.

Check setting of hydraulic relief valve (para 2-48b(2), step 20).

a. If pressure indication is 2500 to 2550 PSI, proceed to MALFUNCTION 2, HYDRAULIC

OIL FOAMING

b. If pressure indication is not 2500 to 2550 PSI, adjust relief valve (para 2-48b(2), step 23).

If adjusting relief valve does not change pressure indication, replace relief valve (para 2-48b(2)).

If adjusting relief valve changes pressure indication, but will not adjust to 2500 to 2550 PSI,

repair hydraulic pump (para 3-24c).

2. HYDRAULIC OIL FOAMING

Check for air leakage in suction hose, clamps and fittings to hydraulic pump.

a. If air is leaking into suction hose, tighten clamps or replace fittings or hose (para 2-48b(2)).

b. If air is not leaking into suction hose, proceed to MALFUNCTION 3, EXCESSIVE HYDRAU-

LIC PUMP NOISE.

EXCESSIVE HYDRAULIC PUMP NOISE

Step 1.

Check for illuminated HYDRAULIC FILTER indicator light.

a. If HYDRAULIC FILTER light is on, replace hydraulic oil filter (para 2-56g(2)). If

HYDRAULIC FILTER light remains on after changing oil filter, check for clogged

hoses and fittings.

b. If HYDRAULIC FILTER indicator light is not on, proceed to step 2.

Step 2.

Check for plugged hydraulic reservoir strainer (para 2-56g(3)).

a. Clean strainer to remove obstructions (para 2-56g(3)).

b. If strainer is clean, and hydraulic pump operation is still noisy, proceed to step 3.

Check for plugged suction hose and fittings (para 2-48b(2)).

Step 3.

a. Replace obstructed suction hose and fittings (para 2-48b(2)).

b. If suction hose and fittings are not obstructed, repair hydraulic pump (para 3-24c).