Air Drum Brake Adjustment Normal Wear, Eaton

Check your maintenance schedule for the recommended service intervals.

Measure the pushrod stroke in order to determine if the brakes are properly adjusted (1). The pushrod travel should be less than the maximum allowable stroke listed in the Dimensional Specifications Table. Refer to Air Drum Brake Component Specifications .

1. Block the wheels.
2. Perform the Push Rod Stroke Measurement Procedure to see if adjustment is needed.




Important: Automatic slack adjusters should never be manually adjusted in an effort to correct excessive chamber pushrod stroke. Manual adjustment of the automatic slack adjuster can result in a degradation of slack adjuster performance over time. If pushrod stroke is out of adjustment, determine root cause of excess stroke by checking the chamber clevis, clevis pins, brake return springs, camshaft bracket, camshaft bushings, and related foundation brake components for wear or damage. Replace any worn or damaged components. Also ensure that the clevis jam nut is not loose. If the pushrod stroke is still out of adjustment, replace the slack adjuster.

3. To adjust the chamber stroke or slack adjuster setting, perform the following:

3.1.	Loosen the slack adjuster control arm nut (1).

Important: A minimum of 17 N·m (13 lb ft) is necessary to overcome the clutch and a ratching sound will occur during back off.

3.2.	Turn the manual adjusting nut (2, 3) until the brake linings make contact with the drum.

3.3.	Back off the linings by turning the manual adjusting nut (2, 3) 1/2 to 3/4 of a turn in the opposite direction.

3.4.	Spin the wheel end assembly by hand.

3.5.	If brake drag is noted, back off the manual adjusting nut and recheck the push rod stroke measurement.

Notice: Refer to Fastener Notice in the Preface section.

3.6.	Tighten the slack adjuster control arm nut.

Tighten
Tighten the nut to 17 N·m (13 lb ft).

Air Drum Brake Adjustment Arvin-Meritor

Check your maintenance schedule for the recommended service intervals.

Measure the pushrod stroke in order to determine if the brakes are acceptably adjusted (1). The pushrod travel should be less than the maximum allowable stroke listed in the Dimensional Specifications Table. Refer to Air Drum Brake Component Specifications .

1. Block the wheels.
2. Perform the Push Rod Stroke Measurement procedure to see if adjustment is needed.




Important: Automatic slack adjusters should never be manually adjusted in an effort to correct excessive chamber pushrod stroke. Manual adjustment of the automatic slack adjuster can result in a degradation of slack adjuster performance over time. If pushrod stroke is out of adjustment, determine root cause of excess stroke by checking the chamber clevis, clevis pins, brake return springs, camshaft bracket, camshaft bushings, and related foundation brake components for wear or damage. Replace any worn or damaged components. Also ensure that the clevis jam nut is not loose. If the pushrod stroke is still out of adjustment, replace the slack adjuster.

3. To adjust the chamber stroke or slack adjuster setting, perform the following:

3.1.	Disengage the pawl (1) by using a flat-bladed tool to lift the button on the pawl assembly at least 1/32 inch.

3.2.	Turn the manual adjustment nut (2) 1/8 turn counterclockwise until the linings touch the drum.

3.3.	Back off the linings by turning the manual adjuster nut (2) a 1/2 turn in the opposite direction.

3.4.	Rotate the drum to check for clearance.

3.5.	Remove the flat-bladed tool from the pawl (1).