On disc brakes, the calipers convert hydraulic pressure from the brake pedal into force, pressing the brake pads against the brake disk to generate friction. This is not just a matter of piston size and hydraulic ratio, but also of stiffness, manufacturing tolerances, sealing technology, material choice and finish.
A stiff caliper converts pressure into force efficiently without losing brake pedal stroke on elasticity, which would result in a spongy feel in the pedal. The piston-bore tolerance, the surface roughness of the pistons and the seal technology determine how smooth and sensitive the braking system operates, the material quality and finish protect the caliper against corrosion and provide durability.
Calipers come in two varieties, floating and fixed. A floating caliper is usually equipped with pistons on one side of the disc: to compress the brake pad on the other side of the disc, the caliper body has to slide over its mounting bolts or sliding brackets, hence the term "floating".
A fixed caliper is bolted to the hub, so the body can't move. Therefore, a fixed caliper has pistons on both sides of the disc to compress the brake pads. A fixed caliper is more complex and expensive to manufacture than a floating caliper. As the hub-caliper assembly of a fixed caliper is stiffer, the performance and feedback of fixed calipers is usually better, though the sensitivity to disc unevenness or run-out is bigger.
Brake calipers work in difficult conditions underneath the car, where they are exposed to water, dirt and salt. If this penetrates the seals, it may cause corrosion and seizing of the pistons. On floating calipers, dirt and corrosion can also affect sliding bolts or sliding brackets. When brake pistons or sliding connectors seize, the calipers can't disengage one or more brake pads after braking, causing the pads to wear down quickly, overheat the disc and increase fuel consumption. A sticking front calliper may also cause steering vibration.
When brake calipers fail, they have to be replaced by calipers of the same quality and characteristics as the original caliper. Nipparts therefore offers a wide range of brake calipers in OE-matching quality, covering most of the Asian cars on the market.
Nipparts Brake calipers:
- High quality finish
- High quality seals
- High market coverage
- Overall OE matching quality