Bendix Commercial Vehicle Systems VERSAJUST AUTOMATIC SLACK ADJUSTER - Manual (Page 8)

8
The Bendix ® Versajust ™ Slack Adjuster Troubleshooting Chart
Symptom Cause Remedy
1. Brake Actuator stroke is
too long.
WARNING: Automatic
slack adjusters should
not be manually
adjusted in an effort to
correct excessive push
rod 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.
A. Loose actuator push rod jam nut. A. Reposition components and torque to
specification.
B. Excessive clearance between adapter/
adapter bushing and yoke due to wear.
B. Replace damaged or worn parts.
C. Excessive clearance between
components: yoke pin — yoke link pin —
link yoke pin — body.
C. Replace worn parts.
D. Damaged (worn)
splines on slack or camshaft.
D. Replace damaged parts.
E. Weak or broken brake actuator return
springs. Weak or broken brake shoe
return spring.
E. Replace weak or broken springs.
F. Worn or broken foundation brake
components, including camshaft
bushings, brake chamber bracket, etc.
F. Repair or replace as required per In
Service Inspection.
G. Versajust adjuster mechanism not
functioning.
G. Lubricate, test adjuster mechanism,
conduct in service inspection, repair
components as necessary, replace.
H. Brake drum—worn, excessively
machined, bell-mouthed,
excessive thermal expansion.
H. Replace or repair as required.
I. Damaged Versajust slack adjuster. I. Replace component(s) or slack adjuster.
J. Versajust slack adjuster improperly
installed.
J. Correct installation position.
2. Brakes dragging —
apparent over-adjustment
of brakes.
A. Versajust slack adjuster improperly
installed. Too close to actuator: brakes
can’t fully release.
A. Correct the Versajust slack adjuster
installation.
B. Loose actuator push rod jam nut. B. Reposition components and torque to
specification.
C. Spring brakes not fully retracting. C. Check spring brake release air pressure
and repair or replace air valving as
necessary. Repair or replace spring
brake.
D. Broken foundation brake components,
including camshaft bushings.
D. Repair or replace as required per In
Service Inspection.
E. Vehicle brake torque imbalance. (More
work done by some brakes than others,
thermal expansion of drums).
E. Check other brakes to ensure they are
working. Check air pressure balance
and threshold pressure (refer to Bendix
publication BW1555). Check driver
braking habits, e.g. use of trailer control
valve. Use same friction material on all
axles.
F. Brake drum out-of-round, excessive
thermal expansion.
F. Replace or repair as required.
G. Air system malfunction, not exhausting
completely.
G. Inspect and correct.
H. New lining swells during break-in. H. Back-off adjustment until brakes are free.
CHART 4 - TROUBLESHOOTING SYMPTOM/CAUSE/REMEDY
BW7499 © 2011 Bendix Commercial Vehicle Systems LLC. All Rights Reserved. 03/11 Printed in U.S.A.