"hard brakes" on 1973 GM car

Sorry, not directly a Buick question, but since it is a full-size 73' GM car, it would have the same basic system, if not the exact same set-up. The folks on the Pontiac boards are clueless. My 73' Grand Ville had perfect, powerful brakes until the brake booster went out about a year ago. Since my car was a very early 73' model it has a booster like on the 72' Pontiacs, there were two different styles of boosters on the 73' full-size Pontiacs, as a larger booster was intalled later. The first time, they had sold me the larger one and the brakes were hard. I thought it was faulty, so I took it back and told them it looked different and they said that may be the problem (being one for a later 73), so they sold me one for a 72' Grand Ville- which looks identical to the one removed. The brakes are still harder than they were before and require more pressure to stop the car. We have bled and bled the brakes, checked the rotors/pads/drums/shoes and all are fine. I have been told that the aftermarket boosters were simply not as good as the original. I have been driving the car for about a year like that and the brake are still good, but not as powerful (or requiring as light of a touch) as before. Any suggestions? Thanks!

 

this might sound goofy.....but

do you have a large vacum hose hooked up to the booster??

check that plastic connector thingy....

 

Yep, checked that its secure and even changed the valve - and without it connected, the brakes are very firm, so it is getting some vac.
Thanks.

 

another cause could be a pinched brake line ...


btw...do you have all your old parts....??...ckeck the rod that is behind the booster from the pedal.....


and ....when your original brake booster went out ....did you have this same hard brake thing???

 

So basically it's like trying to stop the car when it is moving and the engine is off.

 

Thanks. Yeah, I have the old brake booster somewhere. The rod from the booster to the pedal is new.

No, before the original booster went out, the brakes were very powerful. Only took the lightest touch to grind the car to a halt.

 

Very much like it, but not quite as bad. There is some power assist, but not nearly as much as when the original booster was on there. It is like the first inch or so down, they seem to be power assisted, but any further down, it seems like the assist is minimal.

Thanks.

 

I bought an new aftermarket booster for my GTO, and it did the same thing. I ended throwing a used original on just to see after playing with everything you could imagine and they worked fine again. It took 3 additional boosters before I got a new one that worked.

 

put the old booster on ...see what you get...

again....then what was the original reason for the booster change....???

 

Oh, the old booster.... it was bad. One day I started the car, it made a loud air sound from under the hood, then the brakes went to the floor.

 

go hit a junkyard put a used booster on ....see what you get..