The Backing Plate Is The Unsung Hero Of Your Braking System

If you look through the wheel spokes of a drum-braked vehicle, you may be able to spot the outer circumference of the backing plate nestled behind the circular brake drum. They are pressed plates of steel that provide a support for the brake shoes and wheel cylinder. Those components then combine to provide an outward pressure and braking force on the rotating brake drum, slowing the car down.

Specific indentations are pressed into the metal sheeting to provide housings for the respective brake components to sit in, creating the basis for the drum to be connected to. The backing plate itself is mounted to the suspension setup, providing a stationery support in relation to the rotating drum.

Dust covers or splash guards on disc brake systems can also be referred to as ‘backing plates’. These components provide a shield from brake dust and water, reducing corrosion of suspension parts. They can also act as a heat shield for fragile non-metal parts like ball joints which can otherwise be damaged by heat from braking friction. In order to stay out of the way of the brake caliper, dust covers are normally shaped like a comma rather than the fully-circular plate found on a drum brake system.

The placement of backing plates mean that they can quickly succumb to erosion as water, salt and grit is splashed up into them, nibbling at their steel construction. This can become troublesome as, despite their relatively simple construction, backing plates can be rather expensive. For example on a 2015 Toyota Yaris, a new backing plate comes in at £83 ($102), which seems pricey for a pressed circle of metal!

Can you think of another ‘forgotten’ car component like the backing plate? Have any of these components corroded away on your daily? Comment below with your exciting backing plate stories!