Drum Brake Service: Single-Anchor, Floating Shoe Designs
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Drum Brake Service: Single-Anchor, Floating Shoe Designs

Although four-wheel disc brakes currently dominate the import brake service market, millions of drum brakes are serviced each day in independent import shops. Thanks to their age, many drum brakes present problems related not only to normal wear, but also to extended age and mileage.

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and master cylinder should also be inspected. If the vehicle comes through the door with brake application complaints like rear wheel lockup or premature disc brake application on slick road surfaces, it’s possible that the combination valve is inoperative. If you’re servicing an ’80s or earlier ­vehicle, be aware that most drum brake master cylinders contain a residual check valve that increases pedal response by maintaining a small amount of hydraulic pressure in the system. To test for residual pressure, firmly apply the brake pedal and then check for a small spurt of fluid when the wheel cylinder bleeder screw is opened. ­Although it’s old technology, be aware that installing a drum brake master cylinder equipped with residual check valves on a disc brake system will cause the disc brakes to drag and wear prematurely. Remember also that residual check valves were designed out of later drum brake ­designs because they were no longer required. 

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                                                               DRUM BRAKE SERVICING TIPS

 

soak the axle hub with quality penetrating oil before removing the brake drum. a light coat of synthetic caliper grease ­applied to the hub will help prevent corrosion after the drum is ­re-installed.

 

 

rapping the brake drum between the lug bolts with a two-pound or larger hammer will generally loosen the drum. in some applications, the brake drum incorporates two threaded puller screw holes designed to expedite drum removal.

 

 

 

when inspecting a drum brake, always inspect the wheel cylinder for leakage by prying away the rubber end cap. because they can’t be successfully honed, aluminum wheel cylinders should be replaced.

 

 

brake return springs not only retract the wheel cylinder pistons, they also allow the brake shoe’s self-adjusters to work correctly. drum brakes ­usually require special tools to remove and install hold-down and return springs.

 

 

The presence of a chamfer usually indicates if a brake drum can be resurfaced. At the minimum, I recommend a shallow cut to true the surface and remove the inner and outer wear ridges.

 

 

 

 

 

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