Brake advice needed for my 1967 GT500!!

[SSIGT500]

My Mustang has the following brake problem and I need some advice on what to do. The car is a 1967 Ford Mustang GT500That I inherited. When I drove it would barely stop and the brake pedal would go to the floor. There was a sucking sound coming from the brake booster. I have replaced the Booster, Master Brake cylinder, and both rear cylinders. Now when I apply the brakes the pedal moves very little and is rock hard. I have no fluid entering the rear cylinders. This happens with the car running or not. I have also disconnected the brake lines from the master cylinder and I am not getting more than a little spray out of the master cylinder. The booster appears to be hooked up correctly. Any advice would be great, and thanks in advance.

[ajd350]

Sounds like you got a bum booster. I just replaced the one on my GT350. It felt normal until you went to step hard on it, then a rock hard pedal and no boost. Kind of hard on the underwear in a panic stop situation. Fine now.

[Bill Collins]

Did you replace the booster/master cylinder as an assembly or did you do each piece individually? If the latter, it sounds like the booster push rod is not properly adjusted. It may be too long. If so, you don't have enough back and forth piston travel inside the master cylinder. This explains the minimal fluid being ejected when you removed the lines and the pedal being hard, as it is reaching the end of its travel too early.

Consult the 1967 Ford shop manual for the proper procedure to follow to adjust the rod length. This may involve fabricating a gauge tool; this is explained in the manual.

Also, did you check the rear brake proportioning valve? This is a brass cylinder in the rear brake line, attached to the floor above the rear axle. If you correct the first problem and still have no rear brake pressure, the valve needs to be rebuilt.

A note of caution: Brake work is not for amateurs! If you aren't proficient at it, spend the money for professional help. The life and car you save may be your own!

[DaltonDavid]

Sage advice from a man who has dealt with more Shelby Mustangs that sat way too long than most of us can ever imagine.......!

[Bob Gaines]

Sage advice from a man who has dealt with more Shelby Mustangs that sat way too long than most of us can ever imagine.......!

And still managed to sell them all. Bob