TM 9-2330 -326 -14&P
H-37. AUTOMATIC SLACK ADJUSTERS (Cont.)
INSTALLATION AND ADJUSTMENT OF AUTOMATIC SLACK ADJUSTERS (ASAs)
Make sure the wheels are chocked before servicing the semitrailer.
Release the parking brake and check that the push rod is fully released.
If the push rod is not fully released, the ASA cannot be installed
properly. Semitrailer movement may cause injury or de ath to personnel
and damage to the equipment.
Chock wheels to prevent semitrailer from moving. Check that the push rod on the air brake
chamber is FULLY RETRACTED. Apply air pressure to release spring brake.
If air pressure is not available, spring brake must be completely caged
back. Install anchor bracket but do not tighten air brake chamber nut,
Proper mounting location is determined by the length of the adjuster arm --5 and 5-1/2 inch
(12.7 and 14.0 cm) adjuster arm lengths utilize the shorter location, 6 and 6-1/2 inch (15.2 and
16.5 cm) lengths use the longer location. Do not tighten anchor bracket fasteners at this time.
Apply "anti-seize" type lubricant to "S" cam spline shaft.
Install the ASA onto the "S" cam shaft with the adjusting hex pointing away from the air brake
chamber. Secure the ASA on the "S" cam shaft. Rotate the 7/16 -inch (11 mm) adjusting hex nut
CLOCKWISE until the clevis hole on the air brake chamber clevis lines up with the ASA arm
clevis hole. Install clevis pin and cotter pin.
Rotate the control arm on the ASA, arm with indicator arrow, away from the adjusting hex
(toward the air brake chamber) until it comes to a definite internal stop. Indicator arrow must fall
within the slot for proper installation. IF THE CONTROL POSITION IS WRONG, TIGHT
BRAKES WILL OCCUR. Tighten all anchor bracket fasteners, making sure the ASA control arm
does not move from its position while tightening the anchor bracket fasteners.
The ASA must be manually adjusted at this time. Rotate the adjusting hex CLOCKWISE, using
a 7/16 -inch (11 mm) box head wrench, until the brake lining contacts the drum. Then back off
the adjuster by turning the adjusting hex COUNTER-CLOCKWISE one-half of a turn. A
minimum of 15 ft -lb (20.3 Nm) is necessary to overcome the internal clutch. A ratcheting sound
will occur. DO NOT USE AN IMPACT WRENCH FOR ANY ADJUSTMENTS.
FINAL INSPECTION: With full air pressure, release spring brake chamber push rod and check
that the "Installation Indicator" arrow is within the slotted area. If arrow is not within slotted area
the control arm must be reset (see Step 3).