5 Tips for Drum Brake Repair
Before setting out to perform drum brake repair services, there are a few things you need to keep in mind. Some of these 5 tips will make the repair job go much smoother and easier, while some are more safety oriented.
1. Specialized Tools
There are a few tools available from manufacturers such as Craftsman, Mac and Snap-On, among others, designed to make drum brake repairs much easier and safer. These tools are:
- Retainer pin tools: These tools are designed to grip the retainer plate (small round plate with a keyed opening in it) and spring, making it easier to compress and rotate, facilitating removal.
- Return spring tools: The tools are designed to make it much easier and safer to remove and install the large, high tension brake pad return springs on the front and rear brake shoes.
- Brake adjusting tool: This tool is shaped in such a way as to facilitate proper adjustment of the rear drum brake shoes. Drum brake shoes that are improperly adjusted will cause the brake pedal to have excessive travel before the brakes are engaged. They can also sometimes impart so much extra pedal travel that the brakes are not allowed to fully or properly engage.
2. Clean Friction Surfaces
The brake friction surfaces must be kept clean. If the friction material on the shoes becomes contaminated with grease, oil or brake fluid, it may be necessary to replace them. If a small amount of sanding with emory cloth or 120 grit sandpaper will not remove the contaminant, the shoes must be replaced. If grease or oil gets on the drum friction surface, clean it off with a clean rag and brake parts cleaner.
Brake drums have a measurement stamped on the outside top or around the rim known as the maximum allowable diameter. If this diameter is reached and resurfacing is necessary, the drum or drums must be replaced. They can be replaced individually as needed. The reason for this measurement is to keep enough of the drum material so as to preclude a catastrophic failure of the drum. Brake drums out of specification have been known to shatter at very inopportune moments.
4. Shoe Placement
When replacing drum brake shoes, always remember that the rear shoe is the one with the longer friction material component. This is because the rearward shoe is the one that performs most of the braking action when moving forward. Reversing the shoes could result in a serious metal to metal condition.
5. Proper Lube
When replacing drum brake shoes, there are four raised 'knuckles' that the shoes sit on, on the backing plate. These should be cleaned with emory cloth, light sandpaper or Scotchbrite pads and brake parts cleaner, then lightly lubed with white lithium grease to facilitate proper movement of the shoes during actuation and release.
If these 5 tips are kept in mind during day to day driving and when performing repairs, your drum brakes will provide many years of trouble-free service.