TM-9-2330-335-14-P

SEMITRAILER, TACTICAL, BREAKBULK/CONTAINER TRANSPORTER, 22-1/2 TON, RESET M871R, M871A1R AND M871A2R

TECHNICAL MANUAL; FIELD AND SUSTAINMENT MAINTENANCE MANUAL (INCLUDES REPAIR PARTS AND SPECIAL TOOLS LIST)

SEPTEMBER 2008

TM-9-2330-335-14-P - Page 583 of 640

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TM 9-2330-335-14&P

0102

FIELD AND SUSTAINMENT MAINTENANCE

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TROUBLESHOOTING SPRING PARKING BRAKE

NOTE

Points covered in this troubleshooting guide are limited and apply to service brake and spring

parking brake actuators.

INSUFFICIENT SERVICE BRAKE APPLICATION WHEN SERVICE PEDAL IS DEPRESSED

000102

1.

Restricted air flow or low air pressure to service chamber.

2.

Worn brake lining or drums worn or cracked.

3.

Improper brake adjustment (auto or manual slack adjusters).

4.

Automatic adjusters not operating properly.

5.

Improper service pushrod-to-slack-adjuster alignment or geometry (refer to vehicle manufacturer’s recommendations).

6.

Bent or broken cam brackets or chamber mounting brackets (cam brakes).

7.

Ruptured diaphragm.

8.

Air leak in lines, fittings, or valves and at actuator clamp ring.

9.

Improper pushrod length (not to vehicle manufacturer’s specifications).

INSUFFICIENT SPRING BRAKE APPLICATION

000102

NOTE

While most of the causes listed for “insufficient service brake application when service pedal is

depressed” will apply here, there are additional items which should be checked.

1.

Broken power spring.

2.

Insufficient size of spring brake or improper output force.

3.

Spring brake was not fully released during brake adjustment.

EXCESSIVE LEAKAGE, SERVICE BRAKE APPLIED

000102

1.

Leaking brake chamber diaphragm.

2.

Leaking hoses, tubes, or fittings.

3.

Faulty valves.

WARNING

Do not loosen or remove chamber clamp ring. Injury or death to personnel could result.

4.

Inspect for leakage at clamp ring. Tighten to 25 to 30 lb-ft (33.9 to 40.7 Nm) torque if leakage is found.

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