Brake Fluid "Disappearing" 57 With Power Brakes

[TJSHEA]

Another stumper for me, which actually is not very hard. Today when starting the car, the brake pedal went to the floor, and there was virtually no, if any, working of the brake shoes to stop the car. I checked the master cylinder and it was virtually empty. I had the brake booster replaced two months ago. The worksheet shows the technician bled the brakes. I did think they were a bit spongy yesterday. They failed today, luckily in the garage. I have paperwork that indicates all of the brake cylinders were replaced about 2000 miles ago (long before I acquired the car). I filled up the master cylinder with brake fluid, started the car, and pumped the brakes about 6 times, and they firmed right up. I tried a couple little test stops and the brakes worked as they should. I am going to get it to a repair place to look the entire system over, but I was curious just where could the brake fluid go? I do not see anything around the wheels, in the engine compartment, or under the car that looks like brake fluid dripping. Any thoughts?

[T-Bird Bob]

Well, the brake booster works with vacuum from the intake manifold.
If it is not sealing perfectly it might suck the brake fluid up and burn it.
Try to see if the booster vacuum line is wet inside.

Good luck!

Bob

[paul2748]

If the brake fluid is leaking thru the booster and into the engine, then you should be getting a lot of smoke out the exhaust.

[paul2748]

If the brake fluid is leaking thru the booster and into the engine, then you should be getting a lot of smoke out the exhaust. I suggest that you bleed all the brakes to make sure there is no air pocket.

[Haz567]

Also check under the drivers side floor mat; just got thru with this problem on a 55. Master cylinder was leaking back into the cockpit, quite a mess!

[TJSHEA]

Thank you all for the info. The booster is new and was put in just a few weeks ago. Hopefully, that is not it, but it seems logical as the previous owner did not have this problem. Anyway, I will do the checks and see what I can find. I think that I will also have someone who is significantly more qualified than I am check the whole system. Can't have a brake issue. If it is the booster, that would be disappointing. I thought if the fluid is being pulled into the exhaust manifold I should see some smoke? I have not seen any. So, I think the whole system needs a close look. Thanks again for the info.