Just installed a complete new power disc brake set from CCP. Included all new lines front to rear, master cylinder, power booster, calipers, rotors and rear disc brakets. Everything installed very easily. I have already bench bleed the master cylinder twice and used a pressure bleeder for the lines. To get the last little bit of air out I used the old 2 person bleeding method, their is no air in the lines. Now for the problem. The car is a 69 Camaro that had orignal front disc brakes and rear drums. When I pump up the brakes with the car off they feel very firm, but when I start the car the pedal is soft and has to go all the way to the floor in order to stop the car. I test drove the car today and it stops, but again I have to push the pedal all the way to the floor to stop the car. I am at the end off my rope here, I have bled at least 2 quarts of fluid through each caliper to make sure all of the air is out. What else could be the problem? Thanks for the help

I had the same problem, turns out I put my calipers on upside down (wrong side) bleeders were on bottom, ar trapped n top, bleed for 3 days til figures out problem. switched calipers, fixed it right up..

Calipers are in the correct position with bleeders at the top. I even unbolted the rear calipers to point the bleeders up at the correct angle when bleeding and tapped them with a rubber mallet as described in the CPP instruction manual to get all of the air out. I do not see air in the lines as being the problem. I am starting to think it either has something to do with the booster pushrod or the rear integrated parking brakes. The rear parking brakes are difficult to setup correctly per the instrucions. Here is a link to the instructions if anyone would like to check them out:

http://www.classicperform.com/Instructions/PDF/BrakeBleed.pdf

How does the parking brake feel? Does it have no resistance? Is the rod from the booster adjustable? Does the pedal return all the way up? Do all 4 corners drag when your pedal gets to the ground? How much space is between the rear pads and the rotor?

How does the parking brake feel? Does it have no resistance? Is the rod from the booster adjustable? Does the pedal return all the way up? Do all 4 corners drag when your pedal gets to the ground? How much space is between the rear pads and the rotor?

The parking brake feels pretty good, it will hold the car if I give it gas. The booster rod is adjustable in regards to making it longer or shorter to reach the brake pedal. When all the way to the ground the car stops OK, does not seem to drag. I am not sure on how much space there is between the rear pads and rotors, looks like they are barley touching the rotors? How much space should there be, I thought that the pads were supposed to barely touch?

Sounds like you still have air. You might try and find someone with a pressure bleeder.

Sounds like you still have air. You might try and find someone with a pressure bleeder.


I used a pressure bleeder as stated above, there is no air in the lines. Anyone else? Thanks

Could there be a problem with the power booster passing air through the diaphragm when you apply pressure on the brake peddle ??. The reason why I am asking is the statement that you had made about the peddle being firm when the vehicle is not running.

i just did the conversion , you can barely move my pedal with out the car running.
You should bleed again the old 2 person way, you must still have air in there, i used a miti vac to start with then finished the manual way.
it takes forever to get all the air out....

i just did the conversion , you can barely move my pedal with out the car running.
You should bleed again the old 2 person way, you must still have air in there, i used a miti vac to start with then finished the manual way.
it takes forever to get all the air out....

After bench bleeding the master cylinder 2 times I pressure bleed the whole system. Then did the old 2 person way to get the last bit of air out. I have ran about 2 quarts through each caliper the old 2 person way and there is no air showing, not even the little champaine type bubbles.

even after i thought all the air was outta mine i gave it one more round and guess what, a little geyser shot up out of my master and then i got more air, after that was out it was perfect.
I'm thinking it was the prop valve not letting full pressure to the fronts, then when it finally gave in it was a cake walk.
I ran about a gallon and 1/2 thru mine.
You may have an other problem, I don't know
Good luck , Joe

I bleed all of the calipers again today. Still when the car is off they pump up pretty firm, but when the car is on the pedal goes to the floor and I have to push pretty hard to stop the car? Anyone else? Thanks

Have you checked the pushrod length between the pedal and booster? It will affect how far the booster pushes on the master when it is under vacuum.
Is the push rod in the correct hole in the brake pedal? The pedal has two holes into which the push rod can go. The upper hole is for manual and the lower is for power.
The pedal will feel firm with no vacuum in the booster (car off) because you are pushing against the spring and diaphrams in the booster. That does not necessarily mean that you have a "firm pedal".
Try looking at the tech at Master Power's web sight.

Have you checked the pushrod length between the pedal and booster? It will affect how far the booster pushes on the master when it is under vacuum.
Is the push rod in the correct hole in the brake pedal? The pedal has two holes into which the push rod can go. The upper hole is for manual and the lower is for power.
The pedal will feel firm with no vacuum in the booster (car off) because you are pushing against the spring and diaphrams in the booster. That does not necessarily mean that you have a "firm pedal".
Try looking at the tech at Master Power's web sight.


I did not check the length of the pushrod. The CPP master cylinder and booster come preassymbled and in the instructions it stated that the pushrod is adjusted from the factory to the correct length. What length should it be and how do I measure it? My brake pedal only has one hole so I do not know if that is the problem or not?

Ok, maybe the pushrod is ok. You shure that there is only one hole in the pedal to attach the pushrod clevis? I thought they all had an upper and lower hole as the same pedals were used in both manual and power brake applications. Are you using the old combination valve, or did you get a new one with the kit? Using a disc/drum valve with disc/disc will definatelly give a problem!

There is usually a metal tab for the brake light switch in the upper hole.
Have someone operate the brake pedal with engine running while you watch the calipers for movement. If something is out of line, the calpers will move and that uses up travel.
David

Ok, maybe the pushrod is ok. You shure that there is only one hole in the pedal to attach the pushrod clevis? I thought they all had an upper and lower hole as the same pedals were used in both manual and power brake applications. Are you using the old combination valve, or did you get a new one with the kit? Using a disc/drum valve with disc/disc will definatelly give a problem!

I made a mistake there are 2 holes and I am in the lower one. The kit came with a new prop valve also.

I took off the master and bench bleed it again. It has no air in it at all. I also plugged the master cylinder off to make sure that it help constant pressure. Hooked it back up and pressure bleed the entire system. Pushed one full quart of fluid through each caliper and everything is still the same? I did pinch off the line to the rear distribution block and found that the pedal firms up alot so I have narrowed the problem to the rear calipers. I just have no idea what else it could be?

I took the cap off the master cylinder and pushed the pedal down and did not get a squirt of fluid from either the front of rear chamber?

I think you need the long booster rod or you'll never get a pedal up. I had that problem on my 68 disc conversion. If someone already said that sorry but I did'nt read all the posts.

Hopefully they gave you the right bore size master cyl. You need 1 1/8" bore.
When you step on the pedal a small spurt of fluid will come out of the replenishment ports in the master cyl, but as soon as the piston moves a little it should stop.

You might have an internal problem in the master cyl, or a pushrod length problem.
http://www.pozziracing.com/Media/twoboosters.jpg
http://www.pozziracing.com/Media/mcrear.jpg
http://www.pozziracing.com/Media/boosterpushrods.jpg

I think you need the long booster rod or you'll never get a pedal up. I had that problem on my 68 disc conversion. If someone already said that sorry but I did'nt read all the posts.

The pedal being at the correct height is not the problem. The problem is when I step on the pedal it is very soft and has to be pushed all the way to the floor to stop the car and it does not stop very good.

I think you need the long booster rod or you'll never get a pedal up. I had that problem on my 68 disc conversion. If someone already said that sorry but I did'nt read all the posts.

Hopefully they gave you the right bore size master cyl. You need 1 1/8" bore.
When you step on the pedal a small spurt of fluid will come out of the replenishment ports in the master cyl, but as soon as the piston moves a little it should stop.

You might have an internal problem in the master cyl, or a pushrod length problem.
http://www.pozziracing.com/Media/twoboosters.jpg
http://www.pozziracing.com/Media/mcrear.jpg
http://www.pozziracing.com/Media/boosterpushrods.jpg

The master cylinder seemed fine when I bench bled it. Then I plugged off the ports and was not able to push in the master cylinder plunger and it held a constant pressure. I believe the pushrod coming out of the booster on the right in the picture is what I have. The master cylinder also looks like the one on the right. How can I measure to make sure that I have the right pushrod in the booster, I do not see how it comes out. Also when I push down on the pedal I do not get a squirt out of the replinish ports. I only get a little movement of fluid in the front chamber of the master cylinder?

the pushrod in the booster just pulls out by hand. If you have the shallow hole in the master cyl, it's probably OK but some have had problems with the pushrod being slightly long, this causes the brakes to stay on when they get hot and can sometimes cause lack of fluid if the replenishment port is not uncovered.

If you unbolt the master cyl, you can feel extra resistance when you push the MC up against the booster, IF the pushrod is too long, it will be pushing the MC piston in. In this case you have to shorten the rod. The pedal rod is should not be pushed in at all by the brake pedal at rest.

I think you said the rear brakes are disc? What kind of calipers are on there?
David

the pushrod in the booster just pulls out by hand. If you have the shallow hole in the master cyl, it's probably OK but some have had problems with the pushrod being slightly long, this causes the brakes to stay on when they get hot and can sometimes cause lack of fluid if the replenishment port is not uncovered.

If you unbolt the master cyl, you can feel extra resistance when you push the MC up against the booster, IF the pushrod is too long, it will be pushing the MC piston in. In this case you have to shorten the rod. The pedal rod is should not be pushed in at all by the brake pedal at rest.

I think you said the rear brakes are disc? What kind of calipers are on there?
David


There is no resistance when putting the master cylinder on so I think I have the right combo. The rear disc brakes from Classic Performance Parts have the intergrated emergency brakes. On the instructions it says there are from a 1980-85 Cadillac Seville Rear Calipers with emergency brakes.

I remember the rear calipers on cadys had a ratcheting piston style adjustment to bring the pads close to the rotors so when you push the pedal the pads conect before you run out of travel. It was adjusted by useing the emergency pedal. But I belive you would have a low emergency pedal if that were it. If the connection between the pedal and the master is without gaps in the adjustments and the master is putting out a good fluid volume and there is no gaps between the pads and rotors. It could only be air or the master is not alowed to return all the way to its stop. (rods too long) pedal to booster or booster to master. Its a head scratcher. The pedal should get hard when there is no engine vacume and soften when its provided. Mabe try wetting down the driveway and do a fast stop to see what brakes do what. I bet it is the backs that are weak from your post (it got better by pinching the rear hose.

Any other ideas? David Pozzi any thoughts? Thanks

the pushrod in the booster just pulls out by hand. If you have the shallow hole in the master cyl, it's probably OK but some have had problems with the pushrod being slightly long, this causes the brakes to stay on when they get hot and can sometimes cause lack of fluid if the replenishment port is not uncovered.

If you unbolt the master cyl, you can feel extra resistance when you push the MC up against the booster, IF the pushrod is too long, it will be pushing the MC piston in. In this case you have to shorten the rod. The pedal rod is should not be pushed in at all by the brake pedal at rest.

I think you said the rear brakes are disc? What kind of calipers are on there?
David


There is no resistance when putting the master cylinder on so I think I have the right combo. The rear disc brakes from Classic Performance Parts have the intergrated emergency brakes. On the instructions it says there are from a 1980-85 Cadillac Seville Rear Calipers with emergency brakes.