SPRING BRAKES DO NOT APPLY

TM 9-2320-270-20-1

TROUBLESHOOTING - CONTINUED

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

61. SPRING BRAKES DO NOT APPLY.

Check parking brake hand valve (1) (TM 9-2320-270-10).

Step 1.

If valve does not release air pressure, bleed off pressure and replace

valve (page 4-731).

Step 2.

Check spring brake valve (2) for damage or leaks by listening for hissing or using

soap solution and watching for bubbles (page 4-1).

If valve is damaged, replace valve (page 4-806).

Step 3.

Check hose no. 612 from parking brake hand valve (1) to spring brake valve (2)

and hose no. 622 from spring brake valve to doublecheck valve (3) for damage

or leaks by listening for hissing or using a mild soap solution and watching

watching for bubbles (page 4-1).

If hoses are damaged or leaking, repair or replace (page 4-609).

Step 4.

Check doublecheck valve (3) for damage or leaks by listening for hissing or using

soap solution and watching for bubbles (page 4-1).

If valve is damaged or leaking, replace (4-731).

Step 5.

Check exhaust port on relay valve (4) for damage or clogs (page 4-1).

If port is damaged or clogged, replace or clean (page 4-785).

TA239726

3-139