How to Maintain and Adjust Drum Brakes

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Glimmerveen, John. "How to Maintain and Adjust Drum Brakes." ThoughtCo, Feb. 11, 2017, thoughtco.com/maintain-and-adjust-drum-brakes-743547. Glimmerveen, John. (2017, February 11). How to Maintain and Adjust Drum Brakes. Retrieved from https://www.thoughtco.com/maintain-and-adjust-drum-brakes-743547 Glimmerveen, John. "How to Maintain and Adjust Drum Brakes." ThoughtCo. https://www.thoughtco.com/maintain-and-adjust-drum-brakes-743547 (accessed September 21, 2017).
01
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Place Bike on Center Stand

Bike on center stand. John H. Glimmerveen

Maintenance for drum brakes is usually restricted to cleaning the drums and shoes periodically, lubricating the lever pivot, and adjusting the cables. Cable adjustment can be made as and when required (as the lever starts to come too far back, for instance) while cleaning of the internals will normally be done during tire replacement.

To facilitate maintenance or brake adjustment, you should always place the bike onto its center stand (where fitted).

Safety Note: The dust from older brake shoes can contain harmful materials such as asbestos. Do not blow the dust from the brake components with compressed air and always use a suitable breathing mask.

02
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Cable Removal

Brake cable adjuster and lever assembly. John Glimmerveen

When working on the front brake, removal of the brake lever will be necessary (to clean and lubricate the pivot) by removing the pivot bolt (A).

Start by backing off the cable adjuster (B), but be sure to align the slot (C) with the front of the holder, as this will facilitate removal of the cable. Next, depress the lever with one hand as you pull hard on the cable. As the lever is released, the cable will come out of the adjuster housing. Remove the cable completely by pulling the round nipple from the lever.

03
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Lubrication

Lubricating a cable. John H. Glimmerveen

With the cable removed, the lever pivot bolt can be untightened, the bolt removed, and the lever lifted out. All of these components should be cleaned in a suitable solvent (brake cleaner from an auto store works well), then dried with compressed air before lightly coating with grease.

Reassemble is a reversal of the disassembly. However, before refitting the cable, it is good practice to lubricate the inner cable. There are a number of manufacturers who supply affordable cable lubricating tools such as the one in the photograph.

04
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Reasembly and Adjsutment of Brake Cables

Motorcycle Brake Cable Removal
John H Glimmerveen. Licensed to About.com

Refitting the cable is made easy by locating the cable end into the lever, pulling strongly on the outer cable, then placing the outer cable onto the adjuster locknut. Once you’ve done that, you can release the lever, pull again on the outer cable and slip it into the adjuster.

The adjuster should be screwed out until there is approximately one-half inch (12 mm) of free play on the lever before the brake begins to bind. For best results, the front brake should be applying its heaviest force when the fingers on the right hand have passed through 90 degrees.

Locating the brake plate (the plate where the shoes are located) in relation to the wheel/drum assembly is important. Ensuring the plate is positioned precisely in the center of the drum will allow the wheel to rotate without rubbing on one of the shoes. To achieve this centralization, the front spindle locknut should be loosened, and the brake applied. With the brake applied, the spindle locknut should be retightened.

05
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Rear Drum Brake Adjustment

Restored BSA Motorcycle
John H Glimmerveen. Licensed to About.com.

Most classic bikes use a steel rod to operate the rear drum brake. Maintenance for brake follows the same procedure as that of the front. 

Adjusting the free play on the rod is achieved by rotating a winged nut at the wheel end of the brake rod. This winged nut falls into indentations at 180-degree intervals. The mechanic should attempt to have a small amount of free play on the brake, and the lever positioned so that his or her foot will depress the lever approximately 3/4" (19-mm) before the brake begins to bind.