Mechanics

Brake Pedal Goes to Floor

Step by step repair guide on how to fix a brake pedal that goes to the floor. This article pertains to all vehicles.

Difficulty Scale: 3 of 10

Tool and Supplies Needed

  • Brake Fluid
  • Small wrench or socket set
  • Shop towels
  • Safety eyewear and clothing
Before beginning work place the car on level ground with the parking brake set.


Brake Pedal On Floor

Step 1 - Check the level of fluid in the brake master cylinder. It is natural for fluid to be a little low if the front or rear brake pads have worn down. If pads are in good shape and the brake master cylinder reservoir is empty, the system is leaking. (Note: Vehicle should not be driven.) Check the rear of the brake master cylinder for fluid leaks, if brake fluid is present the master cylinder seals have failed and the master cylinder needs to be replaced. Visit - Brake master cylinder replacement

Step 2 - Inspect front brake calipers, rear wheel cylinders (drums) or rear brake calipers for leaks, also check the front and rear and flex hoses for any signs of leakage and replace as needed. Visit - Brake system bleed

(Note: if brake fluid has contacted the brake components i.e. brake pads or brake shoes, the brake lining material must be cleaned before use.) If the brake fluid in the reservoir is full, proceed to the next step.

Step 3 - If upon inspection the brake master cylinder fluid is full, the brake master cylinder is bypassing internally. This means the seals inside the master cylinder have failed allowing the fluid from the front of the master cylinder plunger to slip through to the rear of the plunger and back into the fluid reservoir, allowing the brake pedal to go to the floor with out pressurizing. Visit - Brake master cylinder replacement

Step 4 - Axle bearings hold the front and rear wheels true to the axle shaft while allowing the wheel to rotate. If the bearing fails it allows the rotor to move back and forth, forcing the brake pads inward into the caliper. As the brakes are applied the brake pedal it will go to the floor as the caliper fills with fluid. In this case it may take one or two pumps to regain normal operation. Inspect and replace failed axle bearings as needed.

Step 5 - When brake calipers or rear wheel cylinders fail they can allow air into the system when the brake pedal is released. Bleed the brake system by loosening the air bleeders. If air is observed from the bleeder a second time replace the caliper or wheel cylinder and re-bleed system. This condition is rare but it happens. Visit - Brake system bleed

Best Practices

  • Anytime there is a brake system malfunction do not drive vehicle until repaired.

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-11-28)