MAINTENANCE AND LUBRICATION
4-23
Figure 4-13: Slack Adjuster
7.
Observe the guide pointer arrow:
If the guide pointer is above the clevis pointer, adjust
clevis CCW for alignment.
If the guide pointer is below the clevis pointer, adjust
clevis CW for alignment.
8.
Reposition clevis until the guide pointer aligns with
the clevis pointer.
9.
Verify by engaging 1/4” pin through the clevis and
guide.
10. Tighten jam nut to 50 ft.-lbs. torque min.
11. Remove the guide from cam shaft.
12. If the push rod threads extend through the clevis
more than 1/16”, remove clevis and cut rod to length.
13. If the push rod is not fully engaged in clevis body,
install a new push rod - cut to length.
14. Install the slack adjuster on the cam shaft.
15. Rotate the manual adjuster shaft CW until the slack
adjuster arm holes align with the clevis. Install 1/2”
and 1/4” pins and cotter pins.
Adjusting Slack Adjuster
1.
Rotate the manual adjuster clockwise until brake
shoes contact drum.
2.
Back off manual adjuster 1/2 turn. (counterclockwise)
3.
Manually uncage the spring brake.
4.
Build up vehicle air pressure.
5.
Fully apply and release the brakes several times to
check for adequate clearance to all adjacent
components.
6.
Measure the distance from air chamber to 1/2” pin.
Apply brakes with 100-105 psi air pressure and
remeasure distance to 1/2” pins.
7.
The stroke (difference of these two measurements)
must be less than 2 inches.
SLACK ADJUSTER
CLEVIS
PUSHROD
JAM NUT
COTTER PIN
1/2” CLEVIS PIN
COTTER PIN
1/4” CLEVIS PIN
INSTALLATION GUIDE
CAMSHAFT
ADJUSTMENT HEX
slack
