wcsinx

Well I've halfway solved my excessive pedal travel problem which I posted here.
http://forums.corvetteforum.com/zero...720#1546924720

It looks like the booster to clevis rod is about 1/2" too short! Here's a picture of what the rod looks like when it's properly seated in the booster.



And THIS is what it looked like when it was still hooked up the pedal! The rod was pulled completely out of its seat and hence wasn't even getting seated until I pushed the brake pedal about 6". :eek: You can also see how far down the oxidation goes down the rod from being exposed for who knows how many years.



SO! my questions ... does it look like someone either ...

1. installed the wrong booster or
2. snapped off part of that threaded rod?

I'm thinking it's #2 because there's only 4-5 threads on the end of that rod, and the end does look like it's been broken in the past. :nonod:

hmmmm so I wonder if I could get someone to weld on a piece of threaded rod OR get a new rod OR do I have to buy a whole new booster? (hopefully not)

any advice? anyone? Bueler? :(

Aflac

It'd be easier to get a new one IMHO

wcsinx

Do you happen to know how much thread (i.e. how much adjustment) is supposed to be on that rod? I'm assuming it's supposed to have more than 4 threads, but I've seen weirder stuff. :confused:

Kevin_73

If I remember correctly the rod on my 73 has a adjustable cap that screws onto those threads. I believe it had a hemispherical end that fits into the cup in the master cylinder piston, and the threaded end was crimped to keep it from unscrewing on it's own.
It looks like your pushrod has either broken or been cut.

RHD '68 L89

Sorry Kevin, That is the wrong end.The pic shows the end which connects to the pedal, not the master cylinder.
:cheers:

Kevin_73

Oops, you are correct sir. Sorry, my bad. :bb

zwede

The rod that attaches to the pedal only has a few threads. Yours looks correct. I think the problem is at the other end. The rod going to the master cylinder is adjustable but this may be beyond the adjustment range. I'm thinking you have the wrong MC. Take a look at this pic. There were two different designs, each requiring a different booster rod:

http://www.hydroboost.com/products/C...vs-shallow.jpg

wcsinx

errr ... nope, I've verified the MC is the right one for the booster (deep well). The slack is definitely on the pedal side. It's my understanding that there's only one position for the rods on both sides to seat. And that's with the vacuum bladder in its fully "relaxed" position. If I try to adjust out pedal slack on the MC side rod, the net effect will be a distension of the bladder and the constant application of the brakes.

After I pulled the booster and unscrewed the rod from the pedal clevis, there was about 1/2" between the end of the rod in its seated position and the pedal clevis. It was that 1/2" that was creating my excessive pedal travel. Basically when the pedal was all the way up, the rod was actually being pulled out of its seat. Then when I'd go to hit the brakes, I had to push the pedal ~6" before the rod reseated and began pushing on the MC rod. I either need a longer pedal rod or a longer clevis.

I've heard about people having to lengthen that rod when they did a power brakes conversion, but I didn't think there were any 76's that didn't come with power brakes. :confused: Soooo I just dunno ... maybe someone did an AT-> MT conversion and used a set of pedals out of a non power brakes car. Ooooh man isn't following after Bubba fun?

But on the brighter side, I did manage to pull the booster in about 10 minutes flat without removing the seat or dropping the column. :D My secret? The top left nut had been left off by the last guy that installed a booster in my car. I have never been so glad to see a bubbafication. :lolg:


[Modified by wcsinx, 9:00 PM 4/4/2004]

wcsinx

bah! ok, I give up. I have no idea why the pushrod is too short. I'm just going to lengthen it the same way stingry did here ...
http://forums.corvetteforum.com/zero...608#1546632608

:confused: