Brake calipers: failures, tests and reliability
Brake caliper – an element of disc brake mechanism. Depending on the design, brake calipers can be:
Brake calipers can be:
- with fixed staple;
- with floating staple;
Number of pistons:
- single-piston;
- multipiston.
Associated with the vehicle axle:
- Front axle;
- for rear axle with parking brake mechanism.
Signs of a faulty brake caliper
The car pulls to the side.
This behaviour is due to the brake caliper on the front axle being jammed and the wheel not fully releasing.
Greasy smell.
Rear caliper piston jamming is usually manifested by the appearance of a foul burning smell. Because the manifestation of the car will be less noticeable, especially on a front-wheel drive car, and the driver will drive in the usual speed mode. Constantly rubbing pads will cause them to overheat and cause an unpleasant smell of burning.
An unusual noise or knocking noise in the wheel area when driving over bumps.
It is usually caused by the pad's compression spring, which can break or lose its elastic properties. Therefore, the pads will rattle on any bump.
Uneven brake pad wear on one axle of the vehicle. Visually noticeable uneven pad wear on one axle of the vehicle is a sign that one of the calipers is defective.
Brake fluid leakage. A wet, oily spot near the wheel after parking may indicate a leaking caliper.
Causes of caliper failure
The brake caliper is subjected to significant temperature loads and negative environmental effects: dirt, dust, moisture, chemical reagents. That is, the main cause of breakdowns – it is the harsh working conditions of the unit, which causes damage to the dust covers, washing out of lubricant from the caliper guides, as well as corrosion.
The second reason a brake caliper fails – is lack of proper maintenance: periodically lubricate the caliper guides and replace the brake fluid. All brake fluids used in cars are hygroscopic, i.e. they easily absorb moisture from the air. Water in brake fluid leads to corrosion of the piston and internal surfaces of the caliper housing. This in turn leads to accelerated seal wear and leaks.
How to check the caliper? .
The caliper can be checked without disconnecting it from the hydraulic system. However, you will need to disconnect it from the hub or steering knuckle.
Start with a visual inspection. Check for fluid leaks and the integrity of the dust covers. Next, push down on the piston, it should sink in without effort. Then check the smooth movement of the brake caliper bracket. If the caliper is equipped with a mechanical parking brake mechanism, check the smoothness of its operation.
Reliability of the caliper
Whatever the brake caliper design, under equivalent operating conditions their reliability is the same. Calipers usually last more than 7-8 years, after which all rubber parts can be replaced with new ones and the caliper can last the same amount of time.
Repair or buy a new caliper?"
The only way to answer this question is to disassemble the caliper and assess the extent of the damage. If it is sufficient to wash, lubricate and replace seals and dust covers to restore the caliper's functionality, then such repair is reasonable. The price of such repair will be much less than that of a new one, and the resource is approximately the same.
An important point! Repair of calipers by garage car service may not give the desired result. For a serious caliper repair, you should still use a specialised service that has all the necessary equipment and trusted suppliers of spare parts. You can also now often find a service «repair for exchange», which costs a little more than the usual repair, but you immediately get a serviceable caliper with a warranty.
