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rotation easier to see). This rotation indicates that an excessive clearance condition has been
determined by the slack adjuster, and it is making an adjustment to compensate. On each subsequent
brake release the amount of adjustment and pushrod travel will be reduced until the desired clearance
is achieved.
5. See "In Service Checking Procedure" for proper pushrod stroke.
Maintenance
During normal chassis lube, adjusters should be inspected for damage. Check anchor brackets to ensure that
they are tight.
During reline, check the de-adjustment torque. Place a torque wrench on the 7/16" adjusting hex. Turn the
torque wrench counterclockwise and check that the clutch does not slip at a torque less than 13 Ft. Lbs. A
ratcheting sound will occur while backing off. If clutch slips at a lesser torque, the adjuster must be replaced.
Lubrication
The Self-Adjusting Slack Adjuster should be lubricated in conjunction with the lubrication prescribed for
vehicle chassis. The lubrication interval should not, however, exceed 5,000 miles or 3 months. No special
grease is required, however the use of moly-disulphide loaded grease or oil is not recommended since it may
lower friction capabilities in the adjusting clutch parts, and decrease automatic adjustment reliability.
Inspection
1. During normal lubrication intervals, visually inspect slack adjuster and anchor bracket for damage. Check
that anchor bracket is tight and the control arm is in its "Full Release" position. (Refer to Step #3
"Installation Instructions")
2. Maintaining proper brake adjustment and brake balance cannot be accomplished by the slack adjuster
alone. The condition of foundation brake components has a direct bearing on the effectiveness of brake
adjustment; therefore, periodic inspection of these components is necessary.
a. BRAKE CHAMBERS
Check that brake chamber mounting bolts are tight and proper alignment is maintained to avoid
interference between chamber pushrod and chamber housing. Verify that the brake chamber
pushrod length is equal on opposing brake chambers of the same axle
b. CAMSHAFT BUSHINGS
Optimum brake adjustment cannot be achieved when worn bushings are used.
c. WHEEL BEARING ADJUSTMENT
Accurate wheel bearing pre-load is necessary to maintain proper alignment between the brake
drum and brake shoes.
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