Power Brake Problem!!!

I feel like crying... the only thing that I never replaced on my car finally seems to be dying. I have a '69 with power front disc brakes and it isn't stopping very well. A few days ago I drove the car and the wire that holds the cap on the reservoir broke loose, thus I drove the car with the cap half off for about 10 min. Ever since then the car takes a ton of pressure on the pedal to stop. I think the cap slipping off could have caused the problem, but I don't drive the car much so any thing could have broke on it. I just finished bleeding the brakes and that did nothing.... could it be vacuum?
 
having hte cap off the master shouldn't hurt anything if it didn't run out of fluid. If the pedal is hard and it doesn't stop it's more than likely a booster or vacuum problem, you'll need to buy the booster if that is the problem.
 
I noticed there is sound coming from under the dash where the brake connects to the booster, and it sounds almost like a vacuum leak. I don't remember this being there before, so I'm guessing it's the diaphragm leaking. Also, who makes a booster for a '69 power disc brake (original kind)? I looked in NPD's catalogue and didn't see one. I though that there was a way to replace the diaphragm without putting a new booster on.
 
johnsstang04 said:
Also, who makes a booster for a '69 power disc brake (original kind)? I looked in NPD's catalogue and didn't see one. I though that there was a way to replace the diaphragm without putting a new booster on.

Believe it or not, the local parts stores carry them and are MUCH cheaper than mustang parts suppliers. I bought my booster and M/C from autozone for around $130 for my 70. They were $240 at NPD.