Leaking brake fluid

[jpiatchek]

I have a 1964 Daytona with poer disc brakes. The mastercylinder has been losing brake fluid from the resevoir in less than 100 miles. I put the car on the rack and there is no visible signs of leaking anywhere. I do feel some wetness below where the mastercylinder bolts to the power booster. It isn't dripping out, but it is wet to the touch. The brakes work fine when the fluid is full. Any thoughts thanks John

[Gunslinger]

It could be leaking internally in the booster. Also did you check the calipers and the rear wheel cylinders? If so, the booster is the primary suspect.




Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

[jpiatchek]

Does that mean I need a new booster and if so are they readily available?

[41 Frank]

Loosen the bolts holding the master onto the booster, pull it ahead a little and check if you now see more evidence of leakage if so replace or overhaul master cylinder.

quote:Originally posted by jpiatchek

Does that mean I need a new booster and if so are they readily available?

[HarryStude]

If you look under your carpet you may find it is wet. I even have seen them not show signs at all, but more often than not it is the master cylinder. I would bet on it.

PROUDLY MADE IN AMERICA

[jpiatchek]

Is there a good way to tell if itis the master cylinder or the booster causing the problem?

[Skip Lackie]

quote:Originally posted by jpiatchek

Is there a good way to tell if itis the master cylinder or the booster causing the problem?

I think 41Frank already answered your question. If the bottom of the m/c is wet, then it's leaking. It's also possible that the booster is leaking vacuum and sucking fluid out of the m/c -- but it can't do that if the m/c isn't leaking in the first place. You can unbolt the m/c from the booster and still leave the brake lines connected to the m/c -- just move the m/c forward slightly. If it's all wet in there, then you have your proof.

BTW, you said you put the car on a rack and checked for leaks. Small leaks from the calipers or the rear wheel cylinders may not be visible withouut pulling the wheels and the rear drums.

Skip Lackie
Washington DC

[hank63]

Brake fluid doesn't belong inside the booster. Your master cylinder is toast, I expect. No big deal to fix. Be sure to check the master cylinder bore when you have it apart. Look for corrosion / pitting marks. If you find some of those, you have to replace or re-sleeve the master cylinder. I had to fix a leaking master cylinder a couple of months ago in one of my cars. The hardest part was getting it out (fitted under the dash on that brand of cars).
/H

[Dick Steinkamp]

quote:Originally posted by jpiatchek

Is there a good way to tell if itis the master cylinder or the booster causing the problem?

The booster will not cause a fluid leak.

Dick Steinkamp
Bellingham, WA

[jpiatchek]

Thank you all very much for your help. John