CCP disc brake question

[57hardtop4]

A couple of years ago I put CPP front disc brakes on my 57 using their dual stage booster, corvette style 1 in bore master cylinder and prop valve and left my drum brakes on the rear. Braking improvement was very good but I could never get the pedal height I wanted. This week I put their rear disc brakes on in hopes of even better braking and a higher pedal. The braking is even better but still the hard pedal is an inch off the floor after bleeding (till I'm blue in the face) and re-adjusting the booster pushrod and pedal linkage. What can I do to get a higher pedal? They have a 1 1/8 bore master cyl; is this what I need?:cool: Jon

[nunu]

You mention "hard pedal" If you have a hard pedal you are not getting any booster assist. You may have low engine vacuum or too small of a booster. The 1 1/8" master will raise the pedal some but the pedal will be even harder then it is now. The other thing that will cause low pedal is if your booster is mounted "level" and the rod is still attached at the original pedal hole, in other words the pedal ratio is off. Your booster should be mounted at an angle with the rod attached about an inch below the original pedal hole. Measure your engine vacuum at idle to find out how much you have. Less then 14" is too little and you will have the hard pedal feel. Hasn't anyone at CPP discussed this with you?

[57hardtop4]

When I say "hard pedal" I mean the point at which the pads apply the pressure to the rotors and you feel it in the pedal. The booster is working, the vacuum is sufficient, booster angle is correct (up at the front end) and the pedal link is 1 inch lower and straight, as it should be. This is why I can't figure out why the pedal has to move so far to get braking. CPP is open monday and they are just a few miles away. I plan to be on their doorstep at opening time. Thanks for your reply. Jon

[nunu]

When I say "hard pedal" I mean the point at which the pads apply the pressure to the rotors and you feel it in the pedal. The booster is working, the vacuum is sufficient, booster angle is correct (up at the front end) and the pedal link is 1 inch lower and straight, as it should be. This is why I can't figure out why the pedal has to move so far to get braking. CPP is open monday and they are just a few miles away. I plan to be on their doorstep at opening time. Thanks for your reply. Jon



Then 1 1/8" is the only thing left to change.

[557B210]

The other thing that will cause low pedal is if your booster is mounted "level" and the rod is still attached at the original pedal hole, in other words the pedal ratio is off. Your booster should be mounted at an angle with the rod attached about an inch below the original pedal hole.

Nunu....I could be wrong.....However, I don't believe mounting the booster level and attaching the rod clevis to the original hole would necessarily be a problem.....Its usually when you mount the booster at an angle that you have to attach the rod one inch lower.

The easiest way to determine the perfect location for this hole is to find the center of the push rod's vertical travel to ensure that its actuation is as inline with the booster as possible.

1. Gently lift the end of the pushrod until it stops and noting the location where the clevis on the pushrod locates on the pedal arm. You can mark this location.
2. Then gently push the pushrod down until it stops. Mark this location as well.
3. The proper hole location is in the middle between the two marks on the pedal arm. Mark and drill the new hole in the center of the pedal arm. Attach the pushrod to the pedal arm.

Jon....See CPP's Brake Troubleshooting Guide for further info:http://www.classicperform.com/TechBook/BrakeTroubleshoot.htm#pedal

http://www.classicperform.com/TechBook/pedal_hole.gif

[cecil13]

Did you adjust rod between master and booster? I was having the same problem until I adjusted the rod betweeen master and booster. Was unable to properly bleed brakes and picked up about two inches of pedal off the floor.