|
ELECTRIC
BRAKE TROUBLESHOOTING GUIDE
|
|
COMPLAINT |
POSSIBLE CAUSE |
REPAIR PROCEDURE
|
|
NO BRAKES
|
Open circuit
|
Check for broken wires,
loose connections, and improper grounding or faulty connector plug between
car & trailer. |
|
Improperly wired or
inoperative
controller
|
Rewire controller, check
controller operation. |
|
Poor brake adjustment
|
Adjust brakes. |
|
Selective resistor defective
|
Check resistor for loose
connections. |
|
Worn or defective magnet
|
Replacement magnets |
|
Short circuit
|
Check electric circuit |
|
INTERMITTENT
OR
SURGING BRAKES
|
Out of round drums
|
Turn or replace drums. |
|
Inadequate trailer ground
|
Check for proper grounding.
Ground through trailer hitch is inadequate. |
|
Broken magnet lead wires
|
Bench check magnets &
replace if necessary. |
|
Loose wheel bearings
|
Check & adjust bearings. |
|
WEAK
BRAKES
|
Loose connections
|
Check that all connections
are clean and tight. |
|
inadequate trailer ground
|
Check for proper grounding. |
|
short circuit
|
Check electrical circuit. |
|
Selective resistor setting
incorrect
|
Check for proper setting to
avoid too much resistance. |
|
Worn or defective magnets
|
Replace magnets (magnet
power gets better with wear). |
|
Poor brake adjustment
|
Adjust brakes. |
|
Bent
backing
plate
|
Check backing plate flange.
Correct if necessary. |
|
Contaminated lining
|
Check and replace badly
contaminated linings |
|
Excessive load on trailer
|
Check to be sure trailer is
not under braked. Also be sure to have brakes on every axle. |
|
Using trailer brakes only
|
Use of trailer brakes can
cause early fade or loss of friction due to excessive heat. |
|
Inadequate gauge of wire
|
See wiring recommendations. |
|
GRABBING
OR
LOCKING
BRAKES
|
Flanges improperly installed
|
Check flange location. Refer
to axle manufacturer. |
|
Contaminated lining
|
Check & replace badly
contaminated linings. Disconnect red wire on controller. |
|
Controller not modulating
|
Disconnect red wire on
controller. Road test for braking modulation. If modulation is OK check the
red wire.
Bench Test Controller &
replace if necessary. |
|
No selective resistor
|
A selective resister Is
required when brakes have greater power than
is
necessary for the weight on the axle.
Install selective resistor
when necessary |
|
Weak or broken springs
|
Check for weak or broken
springs & replace if necessary. |
|
DRAGGING
BRAKES
|
Brakes incorrectly adjusted
|
Check brake
adjustment. |
|
Electric defect
in
controller
|
Insufficient gap between
controller
contactor strip & coil may cause brakes to drag. |
|
Hydraulic defect
in
controller
|
Excessive residual pressure
in tow car hydraulic system or a 'gummed up' controller cylinder may cause
the controller to be held on slightly. |
|
Flanges improperly installed
|
Check flange location. Refer
to axle manufacturer. |
|
Badly corroded brake
assembly |
Check brake assemblies for
corrosion.
Check to be sure magnet
levers operate freely.
Clean & lubricate brake
assemblies. |
|
Weak or broken springs
|
Check for weak or broken
springs. Replace if necessary |
|
NOISY
BRAKES
|
Lining excessively worn
|
Check and replace if
necessary. |
|
Weak or broken springs
|
Check for weak or broken
springs replace if necessary. |
|
Range improperly located.
Bent backing plates
|
Check & repair if necessary. |
|
Contaminated lining
|
Check & replace badly
contaminated linings. |
|
Improper bearing adjustment
|
Check & adjust bearings.
Check for worn or damaged bearings, replace if necessary. |
|
Brakes incorrectly adjusted
|
Check brake adjustment. |
