BRAKE ADJUSTMENT PART 8: MAINTENANCE AND SERVICE
– 176 – Y53-6032 (R05/10)
• Proper Running Clearance is 0.08” (2 mm) of move-
ment of the brake caliper (approximately the thickness
of a nickel) in the inboard/outboard direction.
• Have a qualified mechanic provide further inspection
if the caliper does not move or appears to move more
than the specified clearance.
Drum Brakes
Have brake drum linings and disc brake pads inspected by
a qualified mechanic for wear at regular intervals accord-
ing to the maintenance schedule. In severe service or off-
highway applications inspect the linings more frequently.
Automatic Slack Adjusters
Periodically check the Brake Chamber Stroke. Replace
the slack adjuster if proper stroke cannot be maintained.
Operational checks of automatic slack adjusters
• Measure brake chamber stroke with the spring brake
released and the air pressure no less than 100 psi
(690 kPa).
• Brake Chamber Stroke is the difference between the
applied and the retracted position of the air chamber
pushrod.
• A correctly installed and functioning auto slack
adjuster will produce the following strokes:
Chamber Type Stroke
36 (rear brakes)
1
1
/2” - 2
1
/4” (38 - 57 mm)
30 (rear brakes)
1
1
/2” - 2” (38 - 51 mm)
16, 20, & 24 (front brakes)
1” - 1
3
/4” (25.4 - 44.4 mm)
02945a
Brake Chamber Stroke
Y53-6032.book Page 176 Monday, May 24, 2010 3:37 PM
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