Brake Master Cylinder repair & replacement made easy

How does a brake master cylinder work?

A brake master cylinder is a crucial part of your car’s braking system. Think of it as the heart of your vehicle’s brakes, converting the pressure from your foot on the brake pedal into hydraulic force that activates the brakes at the wheels. It’s usually located near the brake pedal, typically under the bonnet in the engine bay.

Here’s how it works:

• When you push the brake pedal, it activates the master cylinder’s piston. This piston presses on the brake fluid inside the cylinder, building up hydraulic pressure.

• The brake fluid is then forced through the brake lines, sending this pressure to the brake calipers (on disc brakes) or wheel cylinders (on drum brakes). This pressure forces the brake pads or shoes to clamp down on the brake discs or drums.

• The result of this pressure is that the car slows down or stops as the wheels’ movement is reduced. The harder you press the brake pedal, the more hydraulic pressure is generated, and the more force is applied to the brakes.

• When you release the brake pedal, the hydraulic pressure is relieved, and the brake pads or shoes retract from the discs or drums, allowing the wheels to spin freely again.

Over time, the seals in the master cylinder can wear out, which could lead to brake fluid leaking. If the brake fluid is low or leaking, the braking power will decrease, and your vehicle may experience soft or spongy brakes. If you notice this, it’s essential to get the master cylinder inspected and replaced if needed.

What does a brake master cylinder replacement job involve?

Typically, during a brake master cylinder replacement, the mechanic will follow these steps:
* The mechanic will first check the entire brake system to ensure there are no other issues that could affect performance.

• Next, the mechanic will carefully inspect the brake master cylinder to determine whether it needs to be replaced due to wear or damage.

• If the brake master cylinder is found to be faulty, the mechanic will remove the old one and replace it with a new, high-quality component.

• The mechanic will replace the old brake fluid with fresh fluid to ensure optimal braking performance and prevent any issues with hydraulic pressure.

• The mechanic will then bleed the brake system to remove any air from the brake lines, ensuring that the brake pedal feels firm and responsive.

• Finally, after the replacement is complete, the mechanic will inspect the brake system one last time and, if deemed safe, conduct a test drive to confirm that the brakes are working correctly and efficiently.

How do I know whether I need a brake master cylinder repair or replacement?

Some signs that may indicate the need for a brake master cylinder replacement include:

• Spongy or Soft Brake Pedal: If your brake pedal feels spongy or soft when you press it, this could be a sign of air in the brake lines or a failing master cylinder.

• Decrease in Braking Power: If you notice that your car is taking longer to stop or you need to press the brake pedal harder than usual, it could mean the master cylinder is not generating enough hydraulic pressure.

• Brake Fluid Leak: A brake fluid leak around the master cylinder or elsewhere in the brake system is a clear indication of a problem. Low brake fluid can significantly affect braking performance.

• Brake Warning Light: If the brake warning light on your dashboard comes on, it may be a signal that there’s an issue with the brake master cylinder or another part of the brake system.

• Brake Pedal Goes or Sinks to the Floor: If the brake pedal sinks all the way to the floor when pressed, it’s often a sign of a serious issue with the master cylinder, causing a loss of hydraulic pressure and making it harder to stop your vehicle.

If you notice any of these signs, it’s important to have your brake system inspected as soon as possible to ensure your safety on the road.

Can a brake master cylinder be repaired?

In some cases, minor external issues might be fixed with a repair kit. HOWEVER, because the master cylinder handles such high pressure, it’s usually safer and more reliable to replace it entirely, especially if the seals are worn or there’s internal damage.

Can I drive with a bad master cylinder?

It's not safe. Driving with a bad brake master cylinder can significantly reduce braking efficiency, leading to longer stopping distances or even complete brake failure during emergencies. This puts you and other road users at serious risk of accidents, which could result in severe injury or even be fatal. For your safety, it's best to get a diagnostic inspection from a qualified mechanic as soon as you suspect any issues.

How much does a brake master cylinder replacement cost?

The cost of a brake master cylinder replacement typically ranges from £195 to £315, with an average price of around £245. The exact cost can vary depending on your car’s make and model, as well as the specific parts recommended by the manufacturer for the replacement. Find out what you could save by having your brake master cylinder replaced by ClickMechanic by entering your car reg and postcode in the form above.

What does a ClickMechanic brake master cylinder replacement quote cover?

Unless otherwise stated, your quote covers:

• The cost of the new brake master cylinder and fluid
• The mechanic's travel to your location
• Fitting the parts
• Disposal of the old parts (unless you request to keep them)
• VAT (if applicable)
• 12-month parts and labour warranty

Can the brake master cylinder be replaced by a mobile mechanic?

Yes! A mobile mechanic can carry out this job at your home or workplace. No need to visit a garage — just book online and relax. If your car isn’t driveable, ClickMechanic include collection and delivery, though a recovery fee may apply.