REAR SERVICE BRAKES RELEASE SLOWLY (Cont)

TM 9-2320-285-24-2

3-21. TREADLE VALVE AND BRAKE CONTROLS TROUBLESHOOTING (CONT)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

REAR SERVICE BRAKES RELEASE SLOWLY (Cont)

If rear service brakes on both sides release slowly, repair brake treadle (para 3-23).

If rear service brake on one side releases normally, and rear service brake on other side

releases slowly, repair or replace rear axle brake air chamber on affected side (para 2-51d(2)).

10 TRAILER BRAKES DO NOT RELEASE

Relieve air system of all pressure (para 2-41h(1)).

Disconnect air line from emergency side of tractor protection valve (hose

from air control valve to tractor protection valve).

Install calibrated air pressure gage.

Start engine and allow air system to build to 100 psi pressure.

Depress tractor protection valve.

Watch test gage.

If test gage indication is within 10 psi of AIR PRESS gage indication, repair or replace tractor

protection valve (para 3-24h).

If test gage indicates zero psi or differs from AIR PRESS gage indication by more than 10 psi,

repair or replace air control valve (para 3-24a).

11 TRAILER SERVICE BRAKES DO NOT FUNCTION (CAB GUARD)

Step 1

Relieve air system of all pressure (para 2-41h(l)).

Disconnect air hose connecting brake treadle valve to double check valve (located at bottom of

tractor protection valve).

Start tractor and allow air system to build to 100 psi pressure.

Install calibrated air pressure gage on hose.

Depress brake treadle valve fully.

Watch test gage.

Test gage shall indicate air system pressure (same as AIR PRESS gage indication).

If test gage indication differs by more than 10 psi from AIR PRESS gage indication, repair or

replace brake treadle valve (para 3-23).

If test gage indication is within 10 psi of AIR PRESS gage indication, proceed to step 2 below.

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