Q: Brakes fade and pedal go to the floor

asked by on

I checked the whole brake system for leaks the lines, calipers, and cylinders. Everything is dry no leaks. I got a remanufactured master cylinder and installed it. I bench bled the master cylinder before I hooked up the brake lines. I had good pedal even before I bled out the 4 wheels. I had good pedal with no sinking. I started the car and applied hard pressure to the pedal and it slowly sank to the floor. Double checked everything and no leaks. At this point I assumed it was a bad master cylinder. I went and installed a new one this time. But I still have the same problem. What are the odds I got 2 bad master cylinders? I don't know what else it could be. H E L P !

My car has 175000 miles.
My car has an automatic transmission.

The brake pedal should stay up hard when you have the engine off. As long as you do not see any loss of fluid after system is bled out of any air in the system. You may need to have the ABS module put into bleed mode to get all the air out. A pressure bleeder can also be used to purge out air in the master cylinder. If after bleeding the brake pedal fades all the way to the floor with no loss of fluid the the master cylinder internal leakage is present and needs replaced again. Make sure you have cleaned out the reservoir of any dirt and debris that may cause problem.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Brakes fade and pedal go to the floor

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Multiple pressings to prevent brake pedal going to floor

A failing master cylinder can cause the symptoms you are experiencing. A technician can attach a clear hose to the bleeder of one of the calipers and examine the volume of brake fluid while applying the brake pedal to estimate...

Q: Car runs perfect except for overheating.

There are a lot of problems that can cause overheating. Anything from a stuck thermostat to a leaking head gasket could be the issue. I suggest you have your vehicle diagnosed by a certified mechanic, such as one from YourMechanic....

Q: Car won't start - Chevy

Hi there, thanks for writing in. This sounds like you may have an electrical short somewhere in the wiring behind your dash, or you could also potentially have a grounding problem. If you'd like help with this issue, consider having...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...