Handbrake shoes for your car

Safely park the car Hand brake shoes (hand brake linings) are components that are part of drum brakes. Today, these are mainly components of hand brakes. These ensure that a car doesn't roll off after being parked. That's why they are also called "parking brakes". Evolution of the drum brake Until the late 1960s, the drum brake was the standard braking system used in cars. Even very powerful vehicles, such as, for example, American "muscle cars" with many hundreds of horsepower, were still equipped with drum brakes on all four wheels. The drum brake had several advantages over the disc brakes. For one, as a closed system, they were impervious to dirt and moisture. The braking action was always sufficient due to the large contact surface and finally, anybody could easily learn how to maintain and repair them. However, they had one significant disadvantage: The closed construction meant a slow dissipation of friction heat. Overheating of the brakes always caused a short-term failure of braking action. Thus, the drum brake eventually became no longer safe enough for use in heavy and fast vehicles. A mixed system was common until the late 2000s: Disc brakes at the front, drum brake at the rear. In doing so, the usual distribution of the brake load was taken into account. The main burden of 70% was taken over by the disc brake at the front. Its self-cooling properties made it better-suited for tough loads. The remained was handled by the drum brake at the rear, thus ensuring the vehicle's directional stability during strong braking. Nowadays, full implementation of disc brakes are common, even among small cars. This is partially due to business-related reasons, as increased use of identical parts on vehicles results in lower unit prices. However, the drum brake has another advantage over the disc brake: It can also be operated with a normal cable pull. This is not possible with a disc brake. Therefore, the drum brake remains a popular choice for parking brakes. Function of the hand brake shoes (hand brake linings) The hand brake shoes (hand brake linings) are semicircular elements with pivot bearings at one point, and springs at the opposite point. The cable brake's mechanism moves a wedge that pushes the two semicircular surface elements apart. This presses them against the inner wall of the brake drum. The braking effect is caused by the applied friction force. Once the parking brake is released again, the spring contracts the two hand brake shoes (hand brake linings) again. Then, the parking brake is released again. Parking brake wear Back when the rear drum brake was still used as a parking brake, as well as for regular braking operations, its wear was relatively high. Each braking operation involved the brake pads being pressed against the rotating brake drum and consequently being ground down. In parking brakes, however, the handbrake shoes (hand brake linings) are only pressed against a still-standing drum wall. This significantly reduces its wear. Furthermore, no abrasion can spread inside the drum, which could block all moving elements. Thus, if the handbrake isn't regularly used at speed, only minimal wear occurs at this point. Thus, the main wear on these brakes occurs at the brake cable. It can stretch over time or corrode at the connection points. Yet, what can happen is that the hand brake shoes (hand brake linings) can no longer be released as a result of pollution, corrosion or damage to the resetting mechanism. This will cause them to permanently grind against the drum when driving. Symptoms of this are increased fuel consumption, an unnatural overheating at the wheel or a grinding noise. Replacing the hand brake shoes Hand brake shoes can be replaced the same way as regular drum brakes. The rear wheels are removed, the braking systems disassembled accordingly and worn elements are replaced. Although much less severely strained, the brake drum's remaining wall thickness should be checked whenever changing the brake shoes. Oftentimes, the parking brakes are integrated in the brake disc. Brake drums and brake disc form one unit. Defective brake shoes are often torn. The entire braking system must be thoroughly cleaned prior to Assembly. Specially developed brake cleaner is ideal for this purpose.