Over the years, the Chevy truck has seen two basic brake system designs. The servo-type drum brake system uses unequal length shoes, a cable and lever activated parking brake, and a self-adjuster to keep them adjusted properly. The rear disc brake system uses a single piston caliper, and "Drum in Hat" parking brake system. Both of these systems have common problems with adjustments that are easily handled by the average home mechanic.
Drum Brake Adjustment Problems
Common problems with brake adjustments on the drum brake equipped Chevy trucks center around the self-adjuster mechanism, and the parking brake cables. Lack of maintenance causes these areas to be damaged by corrosion.
To prevent problems, regular inspection and lubrication of the parking brake cables is recommended. Lubrication of the cables and pivot points prevents moisture from accumulating and corroding the cable housing. This prevents parking brakes from sticking when the parking brake pedal is released. This also causes the system to not be adjustable when new shoes are installed. If the cables are frozen in the housings, the only repair is to replace them.
The drum brake self-adjuster mechanism is another area of concern. As the shoes wear, a lever rotates the star wheel on the self-adjuster to spread the shoes closer to the drum surface. The most common problem found in this sub-system is a frozen star wheel. Lack of lubrication during brake servicing allows corrosion to occur, and prevents the wheel from turning when pushed by the lever.
Disc brake adjustment problems
Adjustment problems with the disk brake system on the Chevy truck center around the parking brake. The "Drum in Hat" parking brake uses a small set of brake shoes that are cable activated and located behind and inside the disc to act as the barking brake. There is no self-adjustment provision for this system so it must be done manually. When the shoes are damaged from driving while the parking brake is applied, or through normal use, damage can occur to the friction surface located on the inside of the rotor. This surface is not machinable, and as a result, the disc must be replaced.
