Lesson 1/Learning Event 3
Many faults occur in the brake system that can cause the vehicle to
pull to one side. However, all these faults have one thing in
common: they affect the brake in one wheel causing that wheel to hold
either more or less than the other wheels. If the affected wheel
holds more, the vehicle will pull toward the affected wheel; if it
holds less, the vehicle pulls away from the affected wheel. The most
common faults that cause the brakes to hold unevenly are unequal
brake adjustment, grease or brake fluid on the lining, dirt in the
brake drum, brake drum or rotor scored or rough, different kinds of
brake linings on opposite wheels, primary and secondary brake shoes
reversed in one wheel (on some vehicles), glazed or worn lining,
restricted brake line, weak brake shoe return springs, or sticking
pistons in a wheel or caliper cylinder.
If the inspection indicates that the wheel brakes are at fault, you
must determine the condition of the brake parts in the wheel brakes.
Do this by removing one wheel and brake drum from each axle assembly
and inspecting the brake parts in these wheels. It is reasonable to
assume that the condition of both brake assemblies on one axle will
be about the same. Inspect the condition of the brake drum, brake
lining, brake shoe anchor, holddown springs, retracting (return)
springs, brake shoe adjusting mechanism, and wheel cylinder.