Summary
The primary components of the drum brake system are: the backing plate, the brake drum & brake shoe assembly, the wheel cylinder, retaining clips & springs and automatic brake self-adjuster.
Drum brakes are still found on older vehicles, and on cars with a combination of both disc and drum brakes.
The main components of the drum brake system are:
| Backing plate |
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The backing plate is made from steel and is attached to the steering or suspension components by bolts. It then supports the wheel cylinder, brake shoes and levers. |
| Brake drum & brake shoe assembly |
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The brake drum fits over the brake linings and forms the braking surface for these linings.
The brake shoe assembly consists of the steel shoe and the brake lining material. |
| Wheel cylinder |
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The wheel cylinder is attached to the backing plate. The pistons push against the brake shoes, which then make contact with the brake drum to slow or stop the vehicle. |
| Retaining clips & springs |
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The brakes are held against the backing plate by retaining clips and springs.
The hold down spring is used to retain the the brake shoe in position in relation to the backing plate. During vehicle operation it keeps the brake shoe in position. |
| Automatic brake self-adjuster |
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To manually adjust the brakes it may be necessary to release the adjusting lever away from the star wheel. To do this, insert a small screwdriver through the adjust slot in the backing plate and push on the adjusting lever. A brake adjuster can now be used to adjust the brakes in the usual way. |
