Car Repair Advice by Professional Automotive Experts.
Troubleshooting
/ Brake Peddle
on Floor
Brake Peddle Goes to the Floor
Troubleshooting Procedure
A. Check the Brake System Fluid Level - Check the level of fluid in the brake
master cylinder. It is natural for fluid to be a low if the front or rear brake
pads have worn down, but if the pads are in good condition you might have a
brake fluid leak. If the brake
master cylinder
reservoir is empty or is very low you have a leak somewhere in the system. Inspect
front brake calipers,
rear
wheel cylinders (drums) or
rear
brake calipers and flex hoses front and rear of vehicle and look for any sign
of fluid leakage. Also 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. Replace any parts that are leaking or show signs of previous
leakage. Refill and bleed the brake system as needed. (note: if brake fluid has
contacted the brake components i.e.
brake pads or
brake shoes the brake lining material is contaminated and must be replaced)
If the brake fluid in the reservoir is full proceed to the next step.
Brake Master Cylinder
B. Brake Master Cylinder is Full of Brake Fluid - If upon inspection
the brake
master cylinder
is full
of fluid, 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 peddle to go to the floor out pressurizing brake fluid into the
system. Replace
master cylinder
with new unit, bleed system as needed.
C. Failing Axle Bearings - The vehicle
axle bearing
holds the wheel true to the axle shaft while allowing the wheel to rotate. If the
bearing fails it will allow the rotor to move back and forth, forcing the
brake pads inward into the caliper. Then as you apply the brake peddle it will
go to the floor as the caliper fills with fluid. In this case it may take one or
two pumps to the brake peddle to regain normal operation. Inspect and replace failed
axle bearings as needed, finish by bleeding and adjusting the system.
D. Air in Brake System - When
brake calipers or
rear
wheel cylinders fail they can allow air into the system when the brake peddle
is released. Bleed the brake system by loosening the air bleeder, if air is observed
from the bleeder replace the caliper or wheel cylinder and re-bleed system. This
condition is rare but it does happen.
Troubleshooting
/
Brake Peddle
on Floor
Check Manufacturer Specific Brake
Peddle Questions and Answers
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