84
PROBLEM
CAUSE
SOLUTION
Air System (cont'd)
Park/emer brakes won't
release (cont'd).
Park/emer brakes won't hold.
Air reservoir leaks or loose
mounting.
Semi-trailer "Runs-Up" on
tractor.
Poor braking performance.
System or component failure
(cont'd).
System or component failure.
System or component failure.
Check brake linkage.
Uneven brakes.
Check open lines - no kinks,
bends, closed shut-off cocks,
restrictions, excessive elbows.
Check that brake shoes are not
frozen to drums.
Check slack adjuster and chamber/
spring brake push rod alignment
for interference.
Assure slack adjuster and
chamber/spring brake push rod
angle 90° applied with proper
adjustment.
Replace/use rubber grommets with
integral brackets.
Assure slack adjuster and
chamber/spring brake push rod
angle 90° applied with proper
adjustment.
Check gladhand connection.
Assure open lines - no kinks,
bends, closed shut-off cocks,
restrictions, excessive elbows.
Have authorized service center
check for adequate pressure and
timing balance relative to tractor/
trailer application.
Check slack adjuster and chamber/
spring brake push rod angle 90°
applied with proper adjustment.
Check slack adjuster and chamber/
spring brake push rod angle 90°
applied with proper adjustment.
Check open lines - no kinks,
bends, closed shut-off cocks,
restrictions, excessive elbows.
Check a leak free system by
applying service brake and
inspecting.
