phoenix

Everything, and I mean EVERYTHING has now been replaced on my brake system.

I had a ton of problems when I started working on them last year, but the only remaining one was that the brake pedal wouldn't return enough to turn off the brake lights. It would catch a little, just enough to hold it up from hitting the button. I adjusted the push rod and the switch, but still not enough.

I then tried readjusting everything and even got rid of the newly rebuilt master cylinder for a new one. Still nothing. The power booster was freshly rebuilt and was holding a vaccum well, so I couldn't see that as the problem.

So... I took the entire dash apart to change the little return spring in the pedal. I cleaned everything up, put it all back together enough to test it...

The Damn thing still catches

What the heck am I supposed to do now?

I guess that the first step is to return the power booster and get another one, but I don't see how the booster is causing the pedal to catch.


Please help... :mad :mad I've put in way too many hours on this to have no solution. The only good side to all of this is that the dash and steering column are still out so that I can easily replace the booster again. :rolleyes:

MN-Brent

Man this sounds bizarre. Im getting ready to do a similar big job with O-ring calipers, SS lines & new booster. I pray the same doesnt happen to me. Since you swapped the MC 2x, that should rule this out

Is it possible to disconnect the booster from the pedal to see if the pedal has free motion?
Is this done with the car running?
Is the car on jackstands so maybe there is some frame flex coming into play?

Im just throwing out ideas.

Maybe you can try a new booster and return it possibly if it doesnt fix the problem. A BIG PITA!!!

Brent....

Turbo-Jet

These types of things can be frustrating to say the least. When you find yourself in such a situation the best thing is to take a solid break for a week. Then go back at it. The trick in diagnosing these obscure problems is to not assume anything, especially the obvious. Then you must methodically go through the system and either replace or directly eliminate all potential sources. The trick in understanding what is going wrong is to make only one change at a time. It can be tempting to save time by doing a few things at once, but you must resist.

I recently went through a maddening experience of diagnosing the source of a vibrating clutch pedal. The advice above is what I learned, and I wish I thought about it in those terms beforehand.
:cheers:

phoenix

I hear you on the break thing.

I replaced everything last fall and left it alone until now.

I took the entire pedal mechanism out from the firewall and had it on the workbench where I cleaned everything, painted it, replaced the bushings and spring. The pedal moves nice and free until I attach it to the clevis pin on the booster. As soon as I do that, it won't return the pedal freely.

This time, it is without the car running, no vacuum attached, no fluid in the lines. Only the booster and MC are attached. Without the MC attached, there is nothing to push against, so I can't really use that to judge.

As far as I can tell, it can only be the booster. I've got a warranty on it, so I'm going to swap it out for another one tomorrow... assuming that they have one in stock. :rolleyes: :rolleyes: autozone. :eek:

MN-Brent

The booster is the only thing left I need to pick up. Keep us posted if this turns out to be the problem or not.

I was also planning on going to autozone. Ive heard only good results about the power boosters from them on the other forum.

Brent...

Rockn-Roll

Have you tried a stronger spring?

vettfixr

Sounds like the problem isn't a binding pedal but something in the Master Cylinder or the Brake Booster. Be carefull about buying rebuild MCs and boosters. I've heard of a lot of people the had problems with rebuilts and the work that's required to put these assemblies in our C3s isn't insignificant. If you can go for the bucks I'd say buy a new assembly. JMHO. Good luck.

killain

Are you sure the units your getting from autozone are any good? Maybe the pedal isn't whats hanging up. And is the clevis pin and the hasp mechanism allowing the pedal free movement? I agree with Vettfixr, go with a BRAND NEW unit. Most rebuilds are junk. that's why their cheap!


[Modified by killain, 8:48 AM 3/3/2003]

flynhi

Phoenix,
Any tricks in removing the pedal assembly?

phoenix

Yes... definitely take the steering column out. It's impossible with it in there.

Basically, lower the steering column, take off the dash. Disconnect all dash and brake electrical connections. Then remove the steering column.
Disconnect the booster pushrod, unbolt the steering column upper bracket then the steel mounting plate above that. Once this is all removed, then you can take the 4 nuts off the booster fairly easily. Finally, the 4 bolts that go in from the top of the cowl are the ones that hold the front of the pedal assemby. These are the ones that will drop the assembly. If the other brackets are still connected to it, it will all come out at once, but it's pretty heavy, so I removed them all separately.

I've got a bunch of photos if anyone is interested, I'll post them.

Brettmc

Could it be the pedal-to-master cylinder pushrod??

Brett :thumbs:

phoenix

You mean the pedal to booster pushrod?
Yes, it certainly could be. The pushrod for the pedal to booster comes with the power booster. (So does the pushrod from the booster to the master cylinder)

I guess that the pushrod could be slightly bent (although it doesn't look like it) or have something on it (but I cleaned and lubed it). I don't know any more. I'm just really tired of fighting such an annoying problem. :rolleyes:

Monkeywrench

Yep, that's the process alright. I would suggest also getting a very long extension and a universal joint for your pneumatic air wrench. The nuts that held on my booster were rusted solid. And the angle is nto the best to get a lot of torque on a hard wrench. An electric or pneumatic wrench will make quick work of the job.

Good luck. Unles you weigh 95 lbs and are a 10 year old, it's real pain getting up in there


[Modified by Monkeywrench, 10:26 AM 3/3/2003]

GTR1999

Mike, I don't know the size of the push rod but if you need one made longer then let me know. I might have the stock to make one for you.
Gary

phoenix

Thanks Gary. :)

I'm going to swap out the booster for another one (under warranty) first. If that doesn't do it, then I'll be looking for your help. :D:D

2manycars

For what it's worth, the early production 2001 C5s had this very same affliction. It turned out to be a weak return spring INSIDE the power brake booster. Replacing the booster was the fix. I got lucky, and got the updated booster in my car. :)

Having spent all last night working on problem brakes on TWO C3s undergoing restoration, I can painfully (literally) relate to your frustration. :eek:

Good luck!

Love My 72 and 77

I have a brake pedal assembly on ebay with no reserve if it helps?
http://cgi.ebay.com/ebaymotors/ws/eB...405883835&rd=1 :smash: :smash: :smash: