SERVICE MANUAL
7.
Install lock nut (11), yoke (14), pin (13) and
cotter pins (12).
8.
Assemble yoke and lock nut to push rod.
Test
To check for leaks, coat brake chamber around clamp
with soapsuds and apply air pressure to port in
pressure plate (4). No leakage allowed.
Preventive Maintenance
Every month, or every 6,000 km (4,000 miles), brake
chamber push rod travel should be checked. Push rod
travel should be kept at a minimum without brakes
dragging. Excessive travel of brake chamber push rod
shortens the life of the diaphragm. Over travel also
slows braking response.
Once each year, or every 160,000 (100,000 miles),
brake chamber should be disassembled and cleaned.
New diaphragms must be installed. Be sure to use
correct diaphragm return springs when reassembling
chamber or uneven braking may result.
Adjustment
After brake chamber is installed, the brakes must be
adjusted and checks made to be sure linkage does not
bind.
Adjustment
of
push
rod
length
may
be
accomplished by altering the location of yoke. With
brakes applied, the angle formed by the push rod and
slack adjuster must be 90 degrees and all slack
adjusters should be set at the same angle.
With brakes applied, after being adjusted, this angle
should still be no greater than 90 degrees. In other
words, slack adjuster should not go "over center" when
brakes are applied (Fig. 2).
SLACK ADJUSTERS
Slack adjusters provide a method of adjusting brakes to
compensate for brake lining wear and also serve as a
lever during braking operation (Fig. 24).
Slack adjusters were designed to conform to the
development of heavy duty, two-shoe foundation brakes.
During brake operation, the entire slack adjuster
rotates bodily with camshaft. When adjusting brakes,
the worm moves the gear so as to change position of
lever arms in relation to brake camshaft.
Information pertaining to automatic slack adjusters will
be found elsewhere in the
BRAKE section of the Service Manual.
Remove
1.
Remove cotter key and clevis pin from slack
adjuster and push rod clevis
Fig. 24 Section View of Slack Adjuster
2.
Remove snap ring from camshaft.
3.
Slide slack adjuster from end of brake camshaft.
Install
Slack adjuster installation is the reverse procedure of
removal.
Be sure that the spacer washers are installed to provide
a maximum end play of 1.59 mm (.062") with retaining
ring installed.
Two variations of snap ring grooves will be found;
namely a 1.5875 mm (1/16") and 3.1750 (1/8"). The
correct thickness of the retaining ring must be used
when installing the slack adjuster.
CTS-4080W - Page 17
