The Stovebolt Site Forums The Shop Area The HiPo Shop 1957 1/2 ton dual master cylinder conversion

Good morning. I’ve installed a frame mount adapter and dual master cylinder on my 57 Chevy 3100. The parts came from CPP. I’ve replumbed the brake lines and bled the brakes. The only problem I’m still dealing with is if I install the pedal return spring in its original place, the M/C push rod is at an angle such that it doesn’t engage the bore correctly. There’s just one hole in the pedal arm for the pushrod so what can I do the fix this? I did read the tech article by Cletus which was very helpful.

Thank you,
Larry

Are you saying the push rod moves when you put spring on and do you have spring over frame and in the hole in frame or under frame and up thru hole. A picture would help. If the push rod is moving only when spring is on then something else is not lined up right or shifting.

Thanks for your reply. I get a picture today so you can see what I’ve got.

Here’s a couple of pics of my installation. On the stock set up there’s an eccentric bolt holding the lever to the pushrod that allows adjustment of the lever relative to the truck cab. Of course with the cab off I can’t measure it anyway. With the return spring off I can see where the pushrod should be, but I’m stuck on how to install a spring that will work.

ok you should be fine. two things. your doing it with cab off. so once you put the cab back on the peddle rod will not retract that far back and will cause the rod to be more level. Most importantly you will want to adjust the push rod after you get setup so not to have preload on the master otherwise your going to burn up some brakes.
Number 2. if you notice in your picture a small hole on top of frame about 8 to 10 inches back from mount. That is technically your stock position for the stock spring. which gives it a better angle from where you have it now. but looks like the spring that came with that setup is two short and your may be ok where it is. As long as it pulls it back nice and smooth and tight to brake light switch you should be good to go.

this is what my spring looks like.

Thanks for all of your help. I’ll double check, but I think the spring I had was just like the new one. There’s a picture in the factory assembly manual that shows a spring like mine. Maybe it changed in 57 since that manual was for 55. I’ll follow up on this post when I get the cab on.

Larry

yea they just used the springs they had. Mine was 1956 and it had a nice long rusted up spring original. they may have changed in 57 and like they said if they had a spring around it got used stock position or not

You could make a short bracket to drop the brake rod down an inch or so.

You don’t want to do that. It changes the geometry and brake pedal travel will be way off. He will be fine once the cab is back on

And I agree with both of you but doing it with the cab off you can see from the picture the arm is almost straight up. If he puts the peddle on it it’s going to hit him in the shin. No reason to determine if adjust. Need to be made until he checks with cab on and peddle moves to proper stop point from the pictures it looks like it will be level then. If not after cab is on then adjustments brackets and other assorted ways would be valid.

I appreciate all of your ideas. I’m going to install the cab soon, and I’ll take pictures as I go so it will help the next guy who gets stuck.