SERVICE BRAKES SPONGY

TM 10-3930-638-24&P

2-41. BRAKE SYSTEM TROUBLESHOOTING (cont)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

3. SERVICE BRAKES SPONGY

NOTE

If service brakes are spongy, bleed air from brake system as des-

cribed in paragraph 2-43a. If brakes are still spongy, then proceed

to step 1 below.

Step 1.

Check brake lines and connections between hydraulic brake valve and wheel cylinders for brake fluid

a. If connections are leaking fluid, tighten; if brake lines are leaking fluid, replace (para 2-43b).

b. If brake lines and connections are okay, proceed to step 2.

Step 2.

Check hydraulic brake valve for leaking condition (para 2-43c).

a. If hydraulic brake valve master cylinder is leaking fluid, replace it (para 2-43c).

b. If hydraulic brake valve is okay, proceed to step 3.

Step 3.

Place blocks (6 by 6 by 18 inches wood blocks) at each wheel to prevent vehicle from moving.

Remove shipping lock pin from storage area under operator's seat (para 2-4b(1)) and install in chassis.

Ensure that parking brake is applied.

WARNING

Before raising axle off ground, be sure that shipping lock pin is in-

stalled. Failure to do so may cause vehicle to turn and slip off

jack or jack stands causing serious injury or death. If you are in-

jured by falling equipment, obtain medical aid immediately.

Raise one axle and wheels from ground.

Remove both wheel axle shafts and hub and drum assembles (para 2-39f).

Check wheel cylinders for leaking condition or sticking piston (para 2-43a, step 1).

Repeat for other axle and wheels.

a. If wheel cylinder is leaking or piston is sticking, replace wheel cylinder (para 243a).

b. If wheel cylinder is okay, reinstall hub and drum assemblies and axle shafts (para 2-39 f), lower

axle and wheels to ground, remove shipping lock pin (store under operator's seat) and remove

blocks from wheels. Replace or repair hydraulic brake valve master cylinder (para 2-43c(1)).