29
MAINTENANCE
Grease the anchor pins, camshaft bracket bearing and
the spider bushing at four (4) grease fittings. Do Not use
an excessive amount of grease on the anchor pins and
spider bushing. Avoid getting grease on the brake lining
surfaces.
Slack Adjuster
Crewson Brunner Automatic Slack Adjuster
WARNING
This section is valid only for Crewson Brunner
slack adjusters. If your vehicle is equipped with
any other OEM’s slack adjusters, contact the
appropriate OEM for maintenance and
adjustment instructions.
Recommended Preventive Maintenance
Every Three Months or 25,000 Miles
1. Check the condition of the brakes, including drums,
shoes and linings, cams, rollers, bearings, etc.
2. Check for structural damage of the automatic slack
adjuster housing and condition of the boot for cuts, tears,
etc. Replace if necessary.
3. After allowing brake drum to cool to room tempera-
ture, check for correct chamber stroke. See chart below for
correct stroke measurements.
Chamber Type
Maximum Stroke
12
less than 1-3/8”
16
less than 1-3/4”
20
less than 1-3/4”
24
less than 1-3/4”
30
less than 2”
Every Six Months or 50,000 Miles
The Crewson Brunner automatic slack adjusters are
factory lubricated and extensively sealed to protect against
dirt, water, salt and other corrosive elements. Nevertheless,
periodic lubrication is recommended.
Figure 21. Slack Adjuster Lubrication Points
1. Grease the automatic slack adjuster.
(a) The styles of grease plugs or reliefs may
vary according to models.
(b) See Crewson Brunner service data for the
approved types of lubricant.
2. Test adjuster function.
Testing Adjuster Function
Check the operation of the slack adjuster by observ-
ing the auto-check indicator during several applications
of the brakes. The pointer should return to the “Home”
position and not go into the red zone when the brakes
are applied. Another way to check the operation is to
measure the maximum stroke during brake application.
If maximum stroke at 90 psi of the Crewson Brunner
automatic slack adjuster is less than the distance in
the Maximum Stroke Chart below, the adjuster is
functioning properly.
Chamber Type
Maximum Stroke
12
less than 1-3/8”
16
less than 1-3/4”
20
less than 1-3/4”
24
less than 1-3/4”
30
less than 2”
AUTO-CHECK
H
O
M
E
AUTO-CHEC
K
CREWSON
BRUNNER
Boot
Auto-Check
Indicator
Grease Fitting
(Far Side)
Hex Extension