Source: The following post on https://www.motorcyclepowersportsnews.com provides consumers with tips on how to check and service the drum brakes on their recreational vehicles.
AKRON, Ohio – With the addition of systems such as fuel injection, ABS, fancy diagnostics and so on, there are still some things that have not changed, like drum brakes.
Follow these tips when it’s time to service the classic drum brake.
It is important to work in a comprehensive manner when inspecting and servicing drum brakes. Do not assume the problem lies with a specific component. Poor drum brake performance can be caused by a problem with almost any component, and the only way to make sure the system works correctly it to examine it as a whole.
A vehicle owner may bring in a vehicle with poor drum brake performance and ask for new brake shoes. In reality, the vehicle may or may not need shoes. The lack of braking performance may be related to a poorly adjusted brake cable, stretched cable, worn or seized brake cam or a combination of factors.
The mechanical assemblies used in the activation of drum brakes must have the right amount of free play to provide good feel and power. Measure the distance from the lever or pedal at rest to where the resistance of the brake engagement is first felt.
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Adjust the free play to specification with the adjuster nut near the brake cam. The free play will increase with time and wear as the cable stretches and the shoe linings wear away. If the specification cannot be met, the cable may have stretched too far or the brake shoe linings may be worn out.
The brakes should engage evenly on both sides of an ATV.
Some models have the cable adjustment on the lever end. If this is the case, loosen the knurled lock nut and turn the adjuster as need. Tighten the lock nut when finished. On some ATVs, both cables attach at the lever, on this set up the lever operates both front brakes with an equalizer so that both brakes are applied evenly. Always adjust the free play to make sure the left and right brakes engage evenly.
The brake shoes wear out over time. Many drum brakes have an external brake shoe wear indicator. Apply the brakes fully and make sure the indicator is in the specified zone. The brake shoes should be replaced if the indicator exceeds the wear out marking on the brake panel.
The shoes can also be removed and inspected if the brake doesn’t have a shoe wear indicator. Measure the thickness of the linings and compare the measurement to the service specifications.
Inspect the shoe linings for uneven wear or dirt imbedded in the surface. Remove any objects stuck in the surface, and clean with a wire brush. Clean away oil and grease with brake cleaner. If there are any obvious high spots, sand them down for a uniform thickness.
Use steel wool to remove rust from the drum. Spray with brake cleaner to remove grease and wipe clean with a lint free rag. Inspect the brake drum for uneven wear and damage. Measure the drum inside diameter with a machinist’s rule or caliper; measure in several different locations. If any measurement goes beyond the service limit, replace the brake drum.
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