Q: my brake master cylinder leaks fluid but not all the time

asked by on

If I drive the car regularly the brake fluid doesn't leak. But if I park the car for a day or so, I lose brake fluid. It looks like it is coming out of the cap on the reservoir. I assume if there was a break in the reservoir it would leak all the time. Is the system pressurized and somehow forcing the fluid out? The fluid seems to only go down to a point where the brake light goes on in the dash. I'm stumped.and hope you can help. Thanks Doug...

My car has 46000 miles.
My car has a manual transmission.

Hi there. A crack in the master cylinder can cause the issue you’re experiencing. The system itself is not "pressurized" until the cap is closed and the pedal is pressed. When you’re driving, the fluid is continually in motion when the brake pedal is engaged; so it’s possible that the leak is worse when it sits. I would recommend having a professional mobile mechanic come to your location and complete a brake fluid leak inspection, so they can determine what’s causing the leak and recommend the right repairs.

Was this answer helpful?
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. my brake master cylinder leaks fluid but not all the time

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: Rebuilt transmission performs worse than previous one - 1990 Toyota Supra Manual

Depending on how "recently" the transmission was rebuilt, you might first go back to the transmission repair shop and point out the significant change in performance. Perhaps something bumped when the transmission was removed/replaced? Exhaust pipe dented/obstructed? Otherwise, get a...

Q: My car stops when engine gets warm and while I am driving I stop on red light and car suddenly turn off and I have to hit starter

Hello, from what you've described it sounds like you are having several different issues. The starter should have nothing to do with it stalling, but it will have something to do with the car restarting if it doesn't turn the...

Q: Q: Power steering fluid leak

There are a few more parts to check for leaks: There are two lines leaving the pump. There are other hoses to check, and the steering gear can leak from several places. If you would like to have your power...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.