Chevrolet Sonic Repair Manual: Brake Drum Surface and Wear Inspection

Chevrolet Sonic Repair Manual / Chassis / Brakes / Drum Brakes / Brake Drum Surface and Wear Inspection

Special Tools

CH-8001 Dial Indicator Set

For equivalent regional tools, refer to Special Tools.

Warning:

Refer to Brake Dust Warning.

With the brake drum removed, clean the brake shoe lining contact surface of the brake drum with denatured alcohol or an equivalent approved brake cleaner.
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

If the braking surface of the brake drum exhibits one or more of the braking surface conditions listed, the drum requires refinishing or replacement.

Using a brake drum micrometer calibrated in thousandths-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.

Compare the groove, or scoring depth recorded to the following specification: Specification

Brake drum maximum allowable scoring: 0.50 mm (0.020 in)

If the brake drum scoring depth exceeds the specification, or if an excessive amount of scoring is present, the drum requires refinishing or replacement.

Mount the brake drum on a brake lathe.

Mount a dial indicator, CH-8001 indicator (1), or equivalent, and position the indicator button so it contacts the braking surface of the brake drum (2) at a 90 degree angle, approximately 19 mm (0.75 in) from the outer edge of the drum.

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.

Compare the radial runout of the brake drum to the following specification: Specification

Brake drum maximum allowable radial runout: 0.03 mm (0.001 in)

If the brake drum radial runout exceeds the specification, the drum requires refinishing or replacement.

Brake Drum Replacement (J93, J94)

Special Tools CH-41013 Rotor Resurfacing Kit CH-42450-A Wheel Hub Resurfacing Kit For equivalent regional tools, refer to Special Tools. Removal Procedure Warning: Refer t ...

Drum Brake Adjusting Hardware Inspection

Warning: Refer to Brake Dust Warning. Visually inspect the adjuster actuator spring (1) for the following conditions: Excessive stretching Excessive bending Exces ...

Other materials:

Safety Belt Pretensioners
This vehicle has safety belt pretensioners for front outboard occupants. Although the safety belt pretensioners cannot be seen, they are part of the safety belt assembly. They can help tighten the safety belts during the early stages of a moderate to severe frontal, near frontal, or rear crash ...

Tire Sidewall Labeling
Useful information about a tire is molded into its sidewall. The examples show a typical passenger vehicle tire and a compact spare tire sidewall. Passenger (P-Metric) Tire Example (1) Tire Size: The tire size is a combination of letters and numbers used to define a particular tire's wid ...

Tire Pressure Monitor Operation
This vehicle may have a Tire Pressure Monitor System (TPMS). The TPMS is designed to warn the driver when a low tire pressure condition exists. TPMS sensors are mounted onto each tire and wheel assembly, excluding the spare tire and wheel assembly. The TPMS sensors monitor the air pressure in ...

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