If you're a little more 'hands on' than most and want to tackle some do-it-yourself jobs on your car or truck, choosing the correct Drum brake and Hardware for your car or truck is a great place to start.
IMPORTANT: Before we go any further it's vital that you never attempt any mechanical work on your car or truck unless you know what you're doing. Make sure you have an experienced assistant nearby, and if in doubt, leave it to the professionals!
Why drum brakes?
All cars sold in United States use disc brakes for the front wheels, because about 70-80% of the vehicle’s stopping power is done by the front wheels.
Even so, the venerable drum brake is still used by some of today’s vehicles, but that is getting less and less every year. One of the reasons of doing this is because the parking brake can be located inside the rear drum brakes whereas with a rear disc brake, it is more expensive to include a parking brake.
The manufacturer can thus offer plain-jane vehicles by offering drum brakes with a parking brake built-in at the rear wheels.
Drum brake advantages
Brake shoes today are still being used. Here are some advantages that drum brakes have over disc brakes:
- Drum brakes can provide more braking force than an equal diameter disc brake.
- Drum brakes last longer because drum brakes have increased friction contact area than a disc.
- Drum brakes are cheaper to manufacture than disc brakes.
- Rear drum brakes generate lower heat.
- Drum brakes have a built-in self energizing effect that requires less input force (such as hydraulic pressure
- Wheel cylinders are simpler to recondition than with disc brake calipers.
- Brake shoes can be remanufactured for future use.
- Drums have slightly lower frequency of maintenance due to better corrosion resistance.
Drum brake disadvantages
- Excessive heating can happen due to heavy braking, which then can cause the drum to distort, and thus cause vibration under braking.
- Under hard braking, the diameter of the drum increases slightly due to thermal expansion, the driver must press the brake pedal farther.
- Brake shoes can overheat to the point where they become glazed.
- Excessive brake drum heating can cause the brake fluid to vaporise.
- Grab is the opposite of fade: when the pad friction goes up, the self-assisting nature of the brakes causes application force to go up. If the pad friction is enough, the brake will stay engaged due to self-application, even when the external application force is released.
- Another disadvantage of drum brakes is their relative complexity.
- Maintenance of drum brakes is more time-consuming, compared to disc brakes.
Drum brake hardware plays an important role in controlling noise and allowing the new brakes to stop quietly and efficiently. It is highly recommended that the vehicle’s drum brake hardware be changed along with every brake maintenance.
- Many people are tempted to reuse the old hardware even if new hardware is included in the box. This should be avoided; instead, use brand new hardware every time.
- Drum return springs that pull the shoes back away from the drums when the brakes are released, may be worn, stretched or broken. This causes the brakes to drag.
- The hold-down springs that hold the shoes against the backing plates may be corroded. If they break, the debris can jam itself between the shoes and drum causing the brake to drag or bind.
- Drum brakes as the shoes wear, brake pedal travel would increase were it not for the adjusters. The adjusters, however, are susceptible to corrosion and sticking.
- Adjuster springs, help maintain tension on the adjusters, but lack of its use can allow cables to corrode and stick in place, preventing the parking brake from applying or releasing.
- A special high temperature brake lubricant should be used on the drum brake.