ADJUSTER HEX
ROTATES
CLOCKWISE
DURING
ADJUSTMENT
STRAIGHT
LINE SCRIBED
ACROSS HEX
AND BODY
FIGURE 7 - TESTING ADJUSTER MECHANISM
pressure for this test can be achieved as follows: Build the system pressure up to 100 psi reading on the vehicle gauge. Shut the engine off. Fan the brakes to attain a 90‑95 psi reading. Make and hold a full brake application while the strokes are checked.
4.The Bendix® SureStroke™ indicator is also available as a visual stroke indicator. The SureStroke™ indicator is a metal bracketing system that bolts onto the brake chamber and allows drivers to check the indicator for operating stroke.
IF THE SLACK ADJUSTER DOES NOT AUTOMATICALLY ADJUST THE BRAKES
If the actuator stroke exceeds those shown in the stroke table, inspection of the foundation brake and/or the automatic slack should be performed. Maintenance of the foundation brake may be a factor in the excessive stroke conditions. Inspecting the foundation brake per the Brake Maintenance Inspection presented in this manual should determine how much of the long stroke condition is caused by the condition of the foundation brake. The ASA‑5® slack adjuster can be tested using the instructions presented in
this manual under Testing the ASA‑5® Adjuster Mechanism.
The automatic slack adjuster is not designed to function as a manual adjuster once it is unable to maintain adjustment automatically. Manual adjustment should only be done as a temporary measure to correct brake adjustment in an emergency situation. The routine manual adjustment of an automatic slack adjuster that is still within adjustment limits may shorten its service life. Automatic slack adjusters should not be manually adjusted in an effort to correct excessive pushrod stroke, because this condition indicates
that a problem exists with the automatic adjuster, with the installation of the adjuster, or with related foundation brake components, which manual adjustment will not fix. Replacement of the automatic slack adjuster or other foundation brake components may be necessary. Consult with the manufacturer's troubleshooting guidelines to find and fix the problem.
WARNING: Manual adjustment of automatic slack adjusters is a dangerous practice that could have serious consequences, because it can give the operator a false sense of security about the effectiveness of the brakes, which are likely to go out of adjustment again soon. Do not make manual adjustments of an automatic slack adjuster once it can no longer automatically adjust the brakes. Manual adjustment DOES NOT fix the underlying wheel end adjustment again. As soon as possible, have the vehicle inspected by a qualified technician or consult the manufacturer's troubleshooting guidelines to find and fix the problem.
TESTING THE ASA‑5® ADJUSTER MECHANISM
The following test can be made to determine if the ASA‑5® adjuster mechanism is functioning properly.
1.With the brakes released and the vehicle wheels blocked, de‑adjust the brakes by rotating the manual adjustment hex counterclockwise approximately 1/2 to 1 revolution.
Note: Considerable torque is required to rotate the manual adjustment hex counterclockwise and should be considered normal. The required torque may be as high as 70 foot pounds.
2.Using a straight edge, scribe a line across the manual adjustment hex head and slack adjuster body. (Refer to Figure 7).
3.Apply and COMPLETELY RELEASE the service brakes several times while observing the manual adjustment hex and the scribed line. The ASA‑5® slack adjuster manual adjustment hex should rotate clockwise during the application and remain stationary during release. No counterclockwise rotation of the hex should be observed. The amount of clockwise rotation (adjustment) will decrease progressively as the brake nears proper adjustment. If the ASA‑5® slack adjuster fails to perform as described, it will be necessary to repair or replace it.
4.Manually readjust the ASA‑5® slack adjuster being tested before returning the vehicle to service. (See section Installation, Step 6)
Note: While it is possible to use the automatic adjustment feature of the ASA‑5® slack adjuster to bring the brake back into adjustment, it will require numerous applications
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