I have a 71 Wagon with disc in the front and about a month and a half ago my master cylinder went out (or so I thought) on the freeway and had to make it home w/o brakes, so I replaced the Master Cylinder and bled it and everything, and my brakes worked well, for about 1 month and 1 week, then the same thing happend again, pedel goes all the way to the floor, brake "Light" comes on (on Dash) and I have no braking power, so I figured faulty master cylinder and replaced it again, then just now (one week later) whil coming home from Dinner I am once again having the same problem, there is no leak visible that I saw, and I have fluid, PLEASE help I do not want to take it and have someone else fix it for a very high price... Sorry about the length of the post, any help would be appreciated :(

boy that is tuff. i have had to go thru 3 or 4 master cylinders before finding a good befor. may just change that again? i know that sucks, maybe someone else will know.
pete.
ps, check out the wagon stuff on my site and team chevelles wagon page if you havent already.

Man i know how frustrating brake problems can be. plus you always seem to run out of fluid right before the final bleed graemlins/angry.gif . anyway are you using new masters or rebuilt? i have heard a bunch of horror stories with rebuilts that resemble your story...then they switched to new masters and problems fixxed. anyway just a suggestion. i feel for you though.

I replaced my brakes about 2 years ago - disc in front and drum in back. Everything was fine until about a month ago. I was getting a soft feeling in the pedal and the brake light was coming on. My brother was in for a visit and we talked about it. Decided to bleed the system and now everything is fine. Pedal feels solid. If you decide to bleed your brakes, make sure you have plenty of fluid on hand.

Sounds like a possible heat related issue with calipers, wheel cylinders, or the proportioning valve. I'd check the calipers first.

Doesn't heat typically cause the fluid to expand applying the brakes?

Or if the brakes didn't move, I'd think the pedal would be rock solid.

Tim.

Thanks for the info guys, Im going out there right now to bleed them :( If that doesnt work I am going to take a step back and think and examine posiible problems, thanks for the info though, and I will try what you guys recomended

Well guys I found the problem, had a friend push the brake while I inspected the lines for awhile and finnally found the leak, thanks for your help guys