phoenix

I spent the greater part of last winter troubleshooting my brake system that was butchered by the previous owner. I have a 1973 and have replaced almost everything in the brake system, but I still have a problem.

I have a rebuilt power booster, new master cylinder, new rubber brake lines, rebuilt calipers and new shoes.

The brakes finally work well, but the problem is that when I release the pedal, it feels as if it gets caught just before pushing the button to turn off the brake lights. I've tried adjusting the booster push rod and the brake pedal push rod, but I can't get it over the little "catch" that is needed to turn off the brake light.

I've been told that I need a new return spring for the pedal by some people, but others say that it's the booster. Rather than ripping apart the entire dash to replace the spring, I figured that I'd again for opinions.

BTW... the system has been bled many times and that has not helped. I am getting a great firm pedal, it's just not returning.

Thanks in advance.

lbell101

Does the pedal come up to the stop? Or does it get hung up before the stop?

phoenix

It's getting hung up before the stop (about 1/4 inch). Just enough so that it doesn't push the brake light button. The brake lights stay on.

I've adjusted the switch out as much as possible and it still won't hit. So for now, until I take the dash apart (unless someone else has any ideas) I have a pad on the stop that makes up the difference. At least the brake lights shut off when I let off the brakes.

When I let off the brakes, the pedal returns well, but gets hung up. I can use my toe to give it a little "help" and then it gets past the catch and hits the button and all is fine. It just won't do it on its own.

:confused:

lbell101

Sounds like a spring or pivot problem to me. Once you get under there, if you disconnect the rod from the pedal assembly you can isolate the problem from the booster. If after it's disconnected it still does the same thing then I would think it has to be either the spring or a worn pivot that's binding.

phoenix

Larry, I tried to do that when everything was disconnected, but you know how tight things are. It seemed like the pedal moved easier without the pushrod attached and I couldn't feel a catch, but the pushrod on the booster also moved without a catch.

The only thing that I could think of was that the resistance of the pushrod was just slightly more than the return spring could handle.

What do you think? Any other way to test this? I'd hate to tear apart the dash and find that the problem was not there.

Kingt

There's not much more, if any, than what Larry said. Have you checked all of the bushings and pivots for wear? And the spring, its almost thirty years old. It's spring rate is probably not what it used to be. I know I would have a lot more spring if I could take off thirty years! :D

:smash:

phoenix

That's what I figured. :( At least the spring is cheap.

Maybe while I'm in there I'll fix up some other things too. :)

How tough is it to replace the spring? Anyone done it before?

Thanks again.

GTR1999

Mike,
I haven't done that job before but I do have the dash out of my 72 automatic car. If you're in the CT area and want to check it out,let me know.
Gary

phoenix

Thanks for the offer Gary. :cheers: I don't know if I'll be able to get there any time soon. Any chance you could snap a couple of pics of the pedal assembly and spring?

One of these days we'll have to get together so that I can buy you that beer (or case) I owe you :D:D

GTR1999

Mike,
I don't have a digital camera but could take some pictures from the roll I have in the camera now. It might be a week or so before I have them though, is that a problem?
Gary

phoenix

Gary, no problem at all. I am in no rush whatsoever. :)

I plan to get at it this winter. :)

TedH

I concur. replace the return spring and any worn pivot points (bushings/washers).

Good luck!

burners

Hey phoenix, have you made any progress on what to do about your problem? I have my brake booster off at the moment and snapped a few pictures of the return spring. I noticed that I could see it from below but you can see it much better thru the hole in the firewall. The spring is bright orange so you can't miss it.





If you need other pictures I will have the booster off until tomorrow sometime. Let me know if I can help anymore.

phoenix

Burners,

Thanks a lot. I'm going to see what I can do next weekend. I'm thinking that it has to be the spring so I'm just going to pull off the dash and get at it.

Nice pics though. I'll see what my spring looks like, it's probably loose.

:)

GTR1999

Mike,
Those pictures look better then I think the ones I took will. They're still in the camera! Sounds like you'll have the dash out before I get the pictures developed. Good luck,
Gary