Brakes always need to be bled after changing rear plate and rotor. If a brake slowly, the pedal feel like there is no brake fluid. If I brake quickly, it's fine but not for long. I need to bleed my brakes every 5 days, but only rear left calippper makes bubble. I can't find any leak. What can cause this?
Chevrolet Optra5 2004
Edit: I was told it is the master cylinder. Is it possible? How can I test it?
Solved: Thanks David Lively, it was the master cylinder. The fluid of the left rear and right front caliper was bleeding slower than the other two. One of the two lines of the master cylinder almost didn't flow. Changing the master cylinder solved the problem.