WARNING
IF THE ADJUSTER APPEARS NOT TO
BE OPERATING, CHECK THE OTHER
BRAKE COMPONENTS FOR PROPER
FUNCTION AND ELIMINATE ANY BIND-
ING. RECHECK THE AUTOMATIC
SLACK ADJUSTER. IF THE ADJUSTER
IS NOT FUNCTIONING, THE UNIT MUST
BE REPLACED BECAUSE FAILURE OF
PROPER ADJUSTMENT FUNCTION
WILL RESULT IN LOSS OF BRAKES.
b. Replacing Slack Adjuster (See Figure
4-14)
1.
Chock wheels to prevent vehicle from
rolling. Release spring and service brake.
Air chamber push rod must be
fully
released.
2.
To maintain a fully released parking brake,
a 90 - 100 psi reservoir pressure must be
maintained. If air pressure is not available
the spring brake must be manually caged.
3.
Remove the existing slack adjuster and
clevis -
DO NOT REMOVE EXISTING JAM
NUT.
4.
Install the new clevis (with 1/2" pin) onto the
push rod up to the jam nut -
DO NOT
TIGHTEN JAM NUT.
5.
Fit the installation guide over the cam
splines so the 1/2" pin slots face the air
chamber.
6.
Swing the guide into the clevis until the
appropriate slot totally engages 1/2" pin.
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.
c. 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 80 - 90 psi air
pressure and remeasure distance to 1/2"
pins.
7.
The stroke (difference of these two
measurements) must be less than 2 inches.
4-24
Summary of Contents for 900B Series
Page 8: ......
Page 12: ......
Page 52: ...4 12 Figure 4 5 Wired Remote Control Diagrams...
Page 53: ...4 13 Figure 4 6 Tandem Triple Axle Air Ride Suspension Figure 4 7 Air Ride Height Adjustment...
Page 56: ...4 16 Figure 4 9 Checking Axle Alignment Figure 4 10 Examples of Camber...
Page 61: ...4 21 Figure 4 13 Axle and Brake Assembly...
Page 71: ...4 31 Figure 4 21 Crank Landing Gear Assembly...
Page 81: ...5 9 NOTES...
Page 82: ......
