Camper Trailers Tech Tips

electric brake trouble shooter

 

 

 

 

 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 songs

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.