Power Booster Conversion - Longer Clevis Needed ??

[Rack Man]

Just installed a new CPP power booster kit.....and from what I've read I should be able to use the stock factory brake pedal clevis....but it appears that I may need a longer one...as I can only catch a few threads of the rod...otherwise I would need to "pre-load" the brakes.

Doesn't seem like its catching enough threads to be safe to me?....Is it normal to have to replace the clevis with one that is like an 1/2" or 1" longer when doing this type of conversion?.....Or is ok to pre-load the brakes a little in order to get it threaded on further?


Thanks,
Dan

[68gmsee]

Some have used an extension collar, others have had a section welded on and others found a donor truck to take it out of. I guess whatever works.

I used the original one on my 69 Chevy with all drum brakes and it worked okay. Even after adjusting it out as far as I dared the pedal was about an 1" lower than before. I just had to keep the brakes adjusted preperly.

[mclairmo]

Do not preload the brakes, that will cause the booster to engage and make the brakes drag or possibly even lock up completely when you do not that them to.

[PanelDeland]

I would check with CPP.My booster came from another source but came with the new clevis and rod assembly.

[Rack Man]

Originally Posted by PanelDeland

I would check with CPP.My booster came from another source but came with the new clevis and rod assembly.

I actually called CPP today and they said that it should fit using the standard clevis....So they were basically no help.....I was thinking that maybe the clevis is actually longer on factory power assist trucks?....or that they actually installed the wrong rod @ CPP

Tonight I messed with it some more and I was indeed able to get it threaded on a bit more without pre-loading the brakes....but now the brake pedal arm will not hit the rubber bump stop on the assembly in the relaxed position?.....and I will need to double check the brakelight switch....but otherwise it should be fine.....If not, I'll just wind up cutting the clevis and welding in a 3/4" extension to it!

[dave2953]

I had the same problem and had to adjust the brake light switch. The brake lights were on when the pedal was at rest. I was able to bend the assembly some and get it to work without a lot of modification.

[Tx Firefighter]

I look forward to the day that CPP goes belly up. So many guys deal with issues like this and they all seem to get the cold shoulder from CPP after the sale.

[gcburdic]

Hey Rack,

This may not help with the clevis issue, but I've also heard that when attaching the rod to the pedal, you have to re-drill another hole above the original one...I just can't remember why you do it...hopefully someone will chime in on that....

[PICKMUP]

OK...You guys...Pay attention again!!! This same old problem goes round and round. NOTE: CPP is right! Use your old clevis. By the way, have you seen their new catalog & and big parts listing??? Don't worry, they are no going anywhere.
Here is the answer: Our trucks run the brake pedal in a lower position on PB systems. STOP trying to cut, weld, sleeve, drill or use two threads on the rod. You are going to kill yourself. Go look at a PB truck and you will see where the pedal sits.
You should be screwing the clevis on the threads at least 3/4"-1", minimum! Then readjust the brake light switch.

[mclairmo]

If there are two holes in the pedal, power brakes use the lower hole and manual brakes use the upper hole for more leverage.

[cparman]

I bought my booster/mc from Master power brakes. Their instructions did show and I did drill a hole 1" lower than the manual brake hole. I tried to get to CPP site, and was not able too a minute ago. I think that if you were to go to their tech/install pages you would be better off than talking to a salesman that probably knows as much as Chloe. She is in my avatar. my booster came with everything I needed, and have done many others in mopar,ford,gm, and never needed any additional parts. I did try to copy and paste a picture from MPB but just aint that smart

[dave2953]

Originally Posted by PICKMUP

Here is the answer: Our trucks run the brake pedal in a lower position on PB systems. STOP trying to cut, weld, sleeve, drill or use two threads on the rod. You are going to kill yourself.

I have to agree with you here. I did it the way the OP is stating and thought I had enough threads to keep it safely attached. Turns out I was wrong. Apparently the vibrations over the course of a year or so took their toll, and it worked it's way loose. It came apart as I was headed down the driveway at my parents farm and I had no brakes. I should have checked it at some point, but never thought about it. I shudder to think how that could have easily turned out much worse, especially for other folks that might have been near me had it happened out on the road someplace.