Electrically actuated brakes have several advantages over other brake actuation systems :
They can be manually adjusted to provide the correct braking capability for varying road and load conditions ;
They can be modulated to provide more or less braking force, this easing the brake load on the towing vehicle ;
They have very little lag time from the moment the towing vehicle’s brakes are actuated until the trailer brakes are actuated ;
In an emergency situation, they can provide some braking independently of the towing vehicle.
Brake Adjustment (not Self-adjusting)
Brakes should be adjusted (1) after the first 300 km of operation when the brake shoes and drums have « seated », (2) at 4500 km intervals, (3) or as use and performance require. The brakes should be adjusted in the following manner :
Jack up trailer and secure on adequate capacity jack stands. Follow trailer manufacturers recommendations for lifting and supporting the unit. Check that the wheel and drum rotate freely ;
Remove the adjusting hole cover from the adjusting slot on the bottom of the brake backing plate ;
With a screwdriver or standard adjusting tool, rotate the starwheel of the adjuster assembly to expand the brake shoes. Adjust the brake shoes out until the pressure of the linings against the drum makes the wheel very difficult to turn ;
IMPORTANT
With drop spindle axles, a modified adjusting tool with about an 80° angle should be used.
Then rotate the starwheel in the opposite direction until the wheel turns freely with a slight lining drag ;
Replace the adjusting hole cover and lower the wheel to the ground ;
Repeat the above procedure on all brakes.
Brake Cleaning and Inspection
Your trailer brakes must be inspected and serviced every 6 months intervals or more often as use and performance requires. Magnets and shoes must be changed when they become worn or scored thereby preventing adequate vehicle braking.
Brake Drum Inspection
There are two areas of the brake drum that are subject to wear and require periodic inspection. These two areas are the drum surface where the brake shoes make contact during stopping and the armature surface where the magnet contacts (only in electric brakes). The drum surface should be inspected for excessive wear or heavy scoring. If worn more than .020" oversized, or the drum has worn out of round by more than .015", then the drum surface should be turned. If scoring or other wear is greater than .090" on the diameter, the drum must be replaced. When turning the drum surface, the maximum rebore diameter is as follows :
7" brake drum - 7,09"
10" brake drum - 10,09"
12" brake drum - 12,09"
12 1/4" brake drum - 12,34"
The machined inner surface of the brake drum that contacts the brake magnet is called the armature surface. If the armature surface is scored or worn unevenly, it should be refaced to a 120 micro-inch finish by removing not more than .030" of material. To insure proper contact between the armature face and the magnet face, the magnets should be replaced whenever the armature surface is refaced and the armature surface should be refaced whenever the magnets are replaced.
WARNING
It’s important to protect the wheel bearing bores from metallic chips and contamination which result from drum turning or armature refacing operations. Make certain that the wheel bearing cavities are clean and free of contamination before reinstalling bearing and seals. The presence of these contaminants will cause premature wheel bearing failure.
Magnets
Your electric brakes are equipped with high quality electromagnets that are designed to provide the proper input force and friction characteristics. Your magnets should be inspected and replaced if worn unevenly or abnormally. As indicated below a straightedge should be used to check wear.
