How a Brake Booster and Master Cylinder Work?
How a Brake Booster and Master Cylinder Work?
Here’s how a brake booster and master cylinder work to stop your vehicle with the press of your brake pedal.
Stopping a heavy, 2000+ lb car is no easy task. It takes a lot of force to press up against the discs and drums on each wheel to stop a car quickly.
Hydraulic principle of brake system
How vehicle brake hydraulics actually work is far easier to grasp than most people think.The main master cylinder piston pushes brake fluid along sealed hydraulic pipes all the way to every wheel assembly. Once pressure builds up, the piston inside each brake caliper — or the wheel cylinder fitted inside drum brakes — expands under fluid force. It then moves steadily to make contact with the brake disc or drum, gradually slowing down wheel rotation to bring the vehicle to a controlled stop.
How the brake booster works
A car’s brake booster runs on vacuum pressure difference, giving extra power to push the brake master cylinder. It draws vacuum supply straight from the engine intake system. When the engine stays at idle, the built-in diaphragm valve lets vacuum flow freely, balancing pressure evenly on both sides of the diaphragm unit.
Tap down the brake pedal, and the internal valve will shift right away, closing off the vacuum passage. At the same time, filtered outside air enters the booster from the brake pedal side. This forms a clear pressure gap on the diaphragm, which lends strong assistance to push and compress the master cylinder piston.
Let go of the brake pedal, and a heavy built-in return spring will pull the entire diaphragm back to its normal resting position effortlessly.
How the master cylinder works
The master cylinder consists of two small pistons in series. Each piston routes to two diagonally opposite wheels, for redundancy in case one springs a leak or the seal is compromised. Reserve brake fluid is contained in a reservoir above the master cylinder and is sucked into the piston assembly when the brake pedal is pushed.
Periodic brake flushes are required because brake fluid is hydroscopic and will absorb moisture and loose its effectiveness over time. Furthermore brake fluid It will wear down with heat and may become contaminated.
The above explains the working principle of the booster and master cylinder in the braking system. If you’re sourcing premium-grade brake boosters and master cylinders for your business, feel free to reach out to Hipsen Brake directly. As an experienced China-based brake parts maker, we cater exclusively to global wholesalers, offering tailored support including product optimization, custom packaging, and private brand OEM solutions.
