Chevrolet Sonic Repair Manual: Drum Brake System Description and Operation
- System Component Description
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The drum brake system consists of the following:
- Drum Brake Shoes
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Applies mechanical output force, from hydraulic brake wheel cylinders, to friction surfaces of brake drums.
- Brake Drums
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Uses mechanical output force applied to friction surface from drum brake shoes to slow speed of tire and wheel assembly rotation.
- Brake Drum Hardware
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Secures drum brake shoes firmly in proper relationship to hydraulic brake wheel cylinders. Enables sliding motion of brake shoes needed to expand toward friction surface of drums when mechanical output force is applied. Provides return of brake shoes when mechanical output force is relieved.
- Brake Drum Adjusting Hardware
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Provides automatic adjustments of brake shoes to brake drum friction surface whenever brake apply occurs.
- System Operation
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Mechanical output force is applied from the hydraulic brake wheel cylinder pistons to the top of the drum brake shoes. The output force is then distributed between the primary and secondary brake shoes as the shoes expand toward the friction surface of the brake drums. The brake shoes apply the output force to the friction surface of the brake drums, which slows the rotation of the tire and wheel assemblies. The proper friction of both the drum brake hardware and adjusting hardware is essential to the proper distribution of braking force.
Drum Brake Hardware Replacement (J93, J94)
Removal Procedure
Warning: Refer to Brake Dust Warning.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
Remove the tire and wheel assembly. Re ...
Parking Brake Adjustment (Drum Brake)
Note: The park brake cable adjusting nut is a nylon lock type. Use
ONLY HAND TOOLS whenever tightening or loosening the adjusting nut.
Apply and fully release the park brake several times ...
Other materials:
Front Bumper Impact Bar Lower Bracket Replacement
Front Bumper Impact Bar Lower Bracket Replacement
Callout
Component Name
Preliminary Procedure
Remove the front bumper opening cover. Refer to Front Bumper Fascia Opening
Lower Cover Replacement.
1
...
Brake Pedal Pushrod Inspection
Disconnect the brake pedal pushrod (2) from the brake pedal.
Reposition the pedal pushrod boot (1) toward the front of the vehicle to
expose as much of the pedal pushrod (2) as possible.
Inspect the brake pedal pushrod (2) for straightness.
If the brake p ...
Fuel Pressure Measurement
Special Tools
EN 34730?E1 Pressure Tester
For equivalent regional tools, refer to Special Tools
Warning: Gasoline or gasoline vapors are highly flammable. A fire
could occur if an ignition source is present. Never drain or store gasoline
or diesel fuel in an open con ...
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