Bremskolben

Bremskolben is a hydraulic brake component that converts the hydraulic pressure generated at the brake master cylinder into linear motion to actuate the braking elements. In disc brake systems, the Bremskolben is located inside the brake caliper bore and may be a single- or multi-piston unit. In drum brake systems, pistons reside in the wheel cylinder and push the brake shoes outward against the drum.

Typical construction uses a metal piston (often aluminum in disc brakes for weight reasons, sometimes steel in high‑temperature applications), elastomer seals and a dust boot to keep dirt out and retain lubricant. The seals allow the piston to move while preventing brake fluid leaks, and the boot protects against contamination and corrosion. The number of pistons and their arrangement influence clamping force, pedal feel and braking balance.

Operation is straightforward: pressing the brake pedal increases hydraulic pressure in the brake lines, forcing the piston(s) to extend and push pads onto a rotor or shoes onto a drum. Releasing the pedal allows return springs and the reduction of pressure to retract the piston. Proper system maintenance relies on clean, undisturbed brake fluid and intact seals; contamination or worn seals can cause piston sticking, leaks, or reduced braking performance.

Common issues include corrosion of pistons, seal wear, or sticking caused by dirt or moisture. When pistons are seized or seals are damaged, components such as the caliper or wheel cylinder may require replacement or rebuilding, often accompanied by a brake fluid purge. Regular inspection helps ensure reliable braking and safe operation.