1965 overly sensitive brakes

[Buck]

I have replaced the original pressure reducer on the front brakes with an adjustable one and have the braking equalized between front and back to prevent sudden lock up when brake applied too quickly which happens a lot because all of the braking occurs in about 1/4" or less about halfway down with the pedal. It is extremely touchy and locks up easily. Has been like this since I bought it. I replaced the master cylinder thinking it could be the problem but then saw that the reducer had been bypassed at some point so added the adjustable one. Still too touchy. Buck

 

[nieuwr]

I wonder how to test the booster?

 

[inspector]

It's possible that the push rod on your booster is not retracting far enough and your master cylinder is not bleeding back into the reservoir. There is a small bleed back hole in the master cylinder and if the piston does not retract far enough it plugs the bleed back hole.

 

[Frankie the Fink]

OK - there are 3 tests for nearly any car's brake booster:
1) Check that the one-way vacuum vale is working (you can do this with your mouth).
2) Start the car up and after a few minutes, shut it off, you should still get 3-5 "boosted" pumps before the vacuum reserve is depleted
3) IMMEDIATELY after test 2 above put your foot firmly on the brake and start the car, the pedal should depress about 1" as the boost gets established.

There is a tool to set the pushrod length and yes, that adjustment can cause brake lock up, dragging or grabbing:

https://www.amazon.com/Adjustment-Briidea-Booster-Boosters-Adjustable/dp/B0BDDBNDBX/?tag=thunderbirdforum-20

Otherwise it can take a lot of tedious trial and error to get things right.

You should check the brake contact areas for contamination (grease, lube, etc) and that they aren't glazed or over-heated. Sometimes a rough-up with some sandpaper can solve the glazing if its not too bad.

 

[Buck]

I have replaced the original pressure reducer on the front brakes with an adjustable one and have the braking equalized between front and back to prevent sudden lock up when brake applied too quickly which happens a lot because all of the braking occurs in about 1/4" or less about halfway down with the pedal. It is extremely touchy and locks up easily. Has been like this since I bought it. I replaced the master cylinder thinking it could be the problem but then saw that the reducer had been bypassed at some point so added the adjustable one. Still too touchy. Buck

Well I have just found out that I have the wrong brake booster on my car!!! I sent a picture to Pat Wilson's and he told me that it is way deeper and definitely wrong.
Does anyone have an old one for a 65 hanging around? Even if it is not good or tested. I will at the least need one for a core. The one on my car is not from a TBird and will not be accepted as a core making the price prohibitive. Or does anyone know where I can get one at a reasonable price? Dan