Elta Automotive looks into the role of the brake shield and why it’s ill-advised to dismiss the part as unimportant.
Although seen on a daily basis, brake shields – sometimes referred to as dust covers, back plates or splash panels – are generally ignored by technicians during a regular service and repair. Perhaps the only exception is when they are removed on the misconception that without them brake cooling can be improved or benefit the vehicle’s aesthetics. However, as vehicle manufacturers are always exploring ways to cut costs and reduce kerb weight, the fact that they fit brake shields means there is a requirement to do so.
Although they are relatively simple in design and made from pressed aluminium, this doesn’t undermine their importance. Brake shields serve to protect the braking system, as well as steering and suspension components, from heat, dirt and debris that would potentially reduce their normal lifespan.
Looking in more detail, the shield protects the brake discs, pads and hoses from dirt and dust contamination produced by both the road and the friction material. In turn, they also contribute to the protection of hot discs, by reducing the amount of sudden cold water that can splash them and cause them to warp or crack. The final element from a braking standpoint is the protection of electronic components such as ABS and brake sensors and their associated wiring, from heat and debris.
Without the brake shield, steering and suspension components would become caked with brake dust, which is a significant cause of corrosion. When on the surface of these parts, the metal filings in the brake dust can oxidise and this can begin to compromise the integrity of the metal.
Rubber parts such as bushes and protective gaiters, or the rubber on shock absorbers for example, can also suffer as the material is prone to drying and cracking, generally as a result of excess heat.
When do they fail?
The primary causes of failure are usually as a result of corrosion, due to prolonged exposure to moisture and road salt. Damage from driving over large debris, potholes or in the event of an accident is also a likely cause.
As an inexpensive part that plays an important role in prolonging the life of more costly components, Elta recommends that brake shields are replaced at the first sign of damage, thereby ensuring the vehicle has the protection it needs, while presenting a professionally finished job.
On older vehicles with drum brakes that have components mounted on them, the MOT manual states they should be inspected for ‘presence and security or brake back plates, wheel cylinders and calipers’ and rejected if ‘a brake back plate, wheel cylinder or caliper securing device is loose, missing or excessively deteriorated’. Disc brake shields/plates on the other hand, are not affected by the MOT unless they are hindering braking performance.