Midland SIDE DUMP GRAVEL TRAILER Operator's Manual page 76

5.2.9 SLACK ADJUSTERS (cont'd)
5.2.9.2 AUTOMATIC SLACK ADJUSTER
MAINTENANCE (cont'd)
AUTOMATIC SLACK ADJUSTERS
While automatic slack adjuster designs vary in the
manner in which they are installed and operate, all are
designed to automatically maintain a predetermined
shoe-to-drum clearance or brake chamber stroke.
Some automatic slack adjusters adjust upon the
brake application stroke, others adjust upon release.
Automatic slack adjusters can greatly reduce manual
adjustments. Automatic slack adjusters do not
reduce the need for periodic maintenance.
Automatic Brake Adjuster Checking Procedures
If the brake adjuster is not maintaining the proper
applied stroke, before removing the brake adjuster,
check the condition of the foundation brake. If after
inspecting the foundation brake no apparent
problems are found, inspect the automatic brake
adjuster to determine if it is operating properly. The
inspection can be performed on or off
the vehicle using the following procedures.
Note:
- Block wheels to prevent vehicle from
rolling.
- Ensure system reservoir pressure is at
90-100 PSI.
- Check that push rod is fully retracted; apply
air to release spring brake.
- If air is not available, spring brake must be
manually caged back.
- Do not use air tools on brake adjuster!
On Vehicle Inspection
64
Automatic Brake Adjuster Operational Check
Functional operation of the brake adjuster can be
performed on the vehicle by using the following
procedure:
- Block wheels to prevent vehicle from
grolling.
- Ensure reservoir pressure is at 90-100
gpsi.
- Check that the push rod is fully
gretracted; apply air to release spring
brake. If air is not available, spring brake
must
be manually caged back.
Manually de-adjust brakes (turn adjustment hex
counterclockwise one full turn) to create an excessive
lining to drum clearance condition. (A ratcheting
sound should occur.)
Make a full service brake application. On release,
allow sufficient time for air chamber to fully retract.
During the brake release, observe rotation of the
adjustment hex (attaching a wrench on the hex or
scribing the hex will make this rotation easier to see).
This rotation indicates that an excessive clearance
condition has been determined by the brake adjuster,
and it is making an adjustment to compensate. On
each subsequent brake release, the amount of
adjustment and push rod travel will be reduced until
the desired lining to drum clearance is achieved.
If rotation of the adjustment hex is not observed,
refer to Foundation Brake Operational Check and
Troubleshooting Procedures at www.haldex.com.
If foundation brake assembly checks out okay
and hex still does not turn, check control arm and
mounting bracket for possible worn, bent or broken
components. If the control arm and mounting bracket
check out okay, replace the adjuster and hardware
per Installation Instructions at www.haldex.com.