What are Backing Plates?
Backing plates are often referred to as ‘brake plates’ and can be found behind the brake shoes.
Backing plates are metal plates that function as the solid foundation for drum brake. Made of steel, these plates have the wheel cylinder mounted on them to which the brake shoes are then attached. Tasked with the parental duties of the brakes, without these metal backing plates, all braking hardware attached would have nothing to grip on to.
Being fixed firmly to the backing plate, brake shoes are provided with the necessary grip and solidity to stop the vehicle via the use of friction.
The use of the term ‘backing plate’ can often cause a lot of confusion when it comes to brakesbecause it may also be referring to a component within disc brake systems. In such systems, the brake shoes have a ‘backing plate’ of which the friction surface is riveted or glued on. These ‘backing plates’ are shaped similar to that of a comma.
On the other hand, brake backing plates located in drum brakes are shaped like somewhat shallow dishes that feature holes used as fasteners. Holding the braking systems together, backing plates functionality can be observed when a driver pushes down on his braking pedal. This motion applies pressure upon the hydraulic fluid found in the brake lines. A wheel cylinder containing two pistons at the top and bottom can be found at the top of the backing plate.
As the hydraulic fluid enters the cylinder forcing the pistons to move outward, the brake shoes are pushed against the inside of the brake’s drum. This action causes the friction component found on the outside edge of the brake shoes to come into contact with the brake drum’s inner surface. Following all these steps and progressions, the result of friction created is what allows your car to slow down and come to a stop.