Drum Brake System: Other Chevrolet Silverado 2500 HD

Brake Drum Diameter Measurement

1. Clean the brake shoe lining contact surface of the brake drum with denatured alcohol or an equivalent brake cleaner.
2. Using a brake drum micrometer calibrated in thousands of an inch, measure and record the largest diameter of the brake drum at 4 or more points, equally spaced around the drum. Ensure that the measurements are only taken within the brake shoe lining contact area and that the micrometer is positioned the same distance from the outside edge of the drum for each measurement.
3. The maximum allowable diameter : Specification: Maximum allowable measurement 296.5 mm (11.673 in)
4. If the largest diameter measurement of the brake drum is less than the maximum allowable diameter, the drum may be able to be resurfaced, depending upon surface and wear conditions which may be present.
5. If the largest diameter measurement of the brake drum is equal to or greater than the maximum allowable measurement, the drum requires replacement.

Tools Required

J 8001 Dial Indicator Set, or equivalent

1. With the brake drum removed, clean the braking (friction) surface of the brake drum with denatured alcohol or an equivalent approved brake cleaner.
2. Inspect the braking surface of the brake drum for the following braking surface conditions: Heavy rust and/or pitting-Light surface rust can be removed with an abrasive disc. Heavy surface rust and/or pitting must be removed by refinishing the drum. Cracks and/or heat spots Excessive blueing discoloration Missing balance weights
3. If the braking surface of the brake drum exhibits 1 or more of the braking surface conditions, the drum requires refinishing or replacement.
4. Using a brake drum micrometer calibrated in thousands of an inch, measure and record any grooves present on the drum braking surface. Ensure that the measurements are only taken within the brake shoe lining contact area.
5. Compare the groove, scoring, depth recorded to the following specification: Specification: Brake drum maximum allowable scoring 1.5 mm (0.06 in).
6. If the brake drum scoring depth exceeds the specification, or if an excessive amount of scoring is present, the drum requires refinishing or replacement.
7. Mount the brake drum on a brake lathe.
8. Mount a dial indicator, J 8001 or equivalent, and position the indicator button so it contacts the braking surface of the brake drum at a 90 degree angle, approximately 19 mm (0.75 in) from the drum's outer edge.
9. Measure and record the radial runout of the brake drum. Rotate the drum until the lowest reading is displayed on the indicator dial, then zero the dial. Rotate the drum until the highest reading is displayed on the dial.
10. Compare the radial runout of the brake drum to the following specification: Specification: Brake drum maximum allowable radial runout 0.06 mm (0.0024 in).
11. If the brake drum radial runout exceeds the specification, the drum requires refinishing or replacement.

J 41013 Rotor Resurfacing Kit

1. Use a micrometer in order to measure the largest diameter of the brake drum. If the largest diameter of the brake drum exceeds the brake drum maximum refinish diameter, DO NOT refinish the brake drum. Replace the brake drum.
2. Use the J 41013 or an equivalent tool in order to THOROUGHLY clean the rust from the brake drum flange.
3. Refinish the brake drum. Refer to the brake lathe manufacturer's operating instructions.
4. After machining the brake drum, use 120 grit aluminum oxide sandpaper in order to create a non-directional braking surface.
5. Clean the braking surfaces with GM P/N 12377981 (Canadian P/N 10953463) or equivalent brake parts cleaner.

Scheme 62

Brake Shoe Replacement

Scheme 63

Rear Brake Backing Plate Replacement

Scheme 64

Drum Brake Adjusting Hardware Replacement

Scheme 65

Wheel Cylinder Replacement