flynhi

I'm losing brake fluid. No evidence of leaks at calipers but the master cylinder always needs to be topped off.
Where is it going?

Larry B.

Depends on how much and how often you need to top it off. As pads wear, the caliper piston moves out and the fluid level drops as the happens. Soft pads wear faster than metalics so.... Excessive topping off may indicate a leak into the power booster if no evidence of leaks elswhere.

427_Roadster

I had the same problem, calipers were new and showed no signs of leakage but the MC was losing fluid. Turned out to be the seal where the plunger attached to the break pedal goes thru the firewall. If your carpet and padding is soaked in that area, that may be what's going on. (I do not have power breaks)
:cheers:
Tom

jerryp58

Agree that the MC is a good candidate, but I don't think the carpets necessarily have to be wet. The fluid could just be going down the firewall, but not be very visible especially with a power brake booster.

flynhi

Thanks for the tips. If the problem might be the power booster, how can I trace it down? Can it be repaired, or do I replace the booster?
W.

jerryp58

The problem wouldn't be in the booster, the booster just hides the leaking brake fluid. That is, your MC could be bad and leaking, but you can't see it because the booster is in the way. Replace the MC and you should be good to go (bench bleeding is always recommended for MCs). You may want to pull the wheels so you can get a good look at the calipers and make sure they're not leaking. I had fluid leaking onto the rotor and didn't know it until I had pulled a wheel and was wondering why my rotors looked so dirty. Turned out they were wet :rolleyes: It'd be good to check all of the brake lines too. The rubber hoses rot after a while and there's always the possibility of a crack in a hard line.

Good Luck.

flynhi

Good tips, Jerry.
I have stainless steel braided brake lines so I don't think that is the problem.
Will

Steve Straus

If you do find that the rear seal on the Master Cylinder is leaking, it would be an excellent idea to clean out the inside of the booster. Brake fluid will eat at the diaphragm and it could eventually cause it to fail.