4
INITIAL INSTALLATION PREPARATION
1. If necessary, carefully remove the manual or automatic
slack adjuster currently installed, including the brake
chamber yoke assembly.
2. Before mounting the ASA-5
™
slack adjuster on the
camshaft, check the brake chamber push rod length to
determine whether shortening or replacement is required.
To accomplish this:
A. With the brake chamber in the released position,
place a square (or equivalent object) so that one edge
is parallel to the actuator push rod while the other
edge bisects the brake camshaft. Measure the
distance from the push rod end to the vertical edge
of the square and compare it to the values in Figure
5.
B. If the measurement is less than the minimum shown
in Figure 5, the brake actuator push rod must be
shortened. If the measurement is greater than the
maximum values, the brake actuator push rod may
require replacement. The extended adapter, available
as a separate service part (5/18"-18 pc. no. 297700
and 1/2"-20 pc. no. 297701) may avoid the need to
replace the brake actuator push rod. The extended
adapter is available for the easy-on yoke assembly
only. Note: Installing any other type of push rod
extender is not recommended, because these
devices may loosen over time and result in an
improperly adjusted brake.
3. Inspect the foundation brake, brake chamber and related
components. Make certain the camshaft bushings and
seals are not excessively worn. Lubricate the camshaft
bushings. Check the brake chamber bracket for cracks
and excessive corrosion. The brake actuator push rod
should not be loose or bent and the return spring should
be firm. Replace parts that are suspect.
4. Wire brush the foundation brake camshaft to loosen
contamination and wipe clean. Depending on
environmental conditions, an application of anti-seize
compound to both the camshaft and worm gear spline
may facilitate later slack removal.
INSTALLATION
1. Select the proper ASA-5
™
slack adjuster.
2. Install the ASA-5
™
slack adjuster on the brake camshaft.
3. If the ASA-5
™
slack adjuster has the easy-on yoke (see
Figure 3), position the brake actuator push rod jam nut
approximately 1-5/16 inches from the end of the brake
actuator push rod. Thread the easy-on yoke adapter on
the brake actuator push rod until it is approximately 3/8
inch from the end of the brake actuator push rod end.
Turn the ASA-5
™
slack adjuster manual adjustment hex
clockwise until the adapter extends into the threaded
bore of the yoke approximately 1/8 inch. Thread the
adapter into the yoke and tighten to 10 foot pounds.
The installation angle of a properly installed ASA-5
™
slack
adjuster:
SLACK "A" STD. "A"
ADJUSTER QUICK CONNECT EXTENDED
ARM OR EASY-ON EASY-ON
LENGTH ADAPTER ADAPTER
5" 1-15/16" - 3-1/32" 2-7/16" - 3-17/32"
5-1/2" 1-15/16" - 3-3/16" 2-7/16" - 3 11/16"
6" 1-3/16" - 3-3/16" 1-11/16" - 3-11/16"
MOUNTING
STUD
SQUARE
DISTANCE
"A"
FIGURE 5 - MEASURING THE BRAKE ACTUATOR PUSH
ROD
BRAKE ACTUATOR
PUSH ROD
Slack Adjuster
Arm Length Angle
5" 99°-113°
5.5" 98°-111°
6" 90°-109°
4. If the ASA-5
™
slack adjuster has the quick connect yoke
(see Figure 4), position the brake actuator push rod jam
nut approximately 1 inch from the end of the brake
actuator push rod. Thread the quick connect adapter
bushing on the brake actuator push rod until it is flush
with the end of the brake actuator push rod. Install the
retaining ring on the adapter bushing, making certain it
FIGURE 6 - INSTALLATION ANGLE
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