Brake pedal travel

After going from front drum to front disc, I have alot of travel in the brake pedal before it reacts. I have bled the brakes numerous times with the pedal pusher method. When the car is off I can press the brake pedal 2-3 times and it gets real stiff and wont move anymore but when I start it the pedal goes down about 3-4 inches from the floor.

I thought there was air still in the system but I don't see any air bubbles in the clear tube when bleeding. :confused:

The pedal getting stiff when the engine is off is normal when you have engine running will it pump up and have a higher pedal if so then you still have air if not then try adjusting the rear shoes a little tighter. just my 2 cents worth.

After going from front drum to front disc, I have alot of travel in the brake pedal before it reacts. I have bled the brakes numerous times with the pedal pusher method. When the car is off I can press the brake pedal 2-3 times and it gets real stiff and wont move anymore but when I start it the pedal goes down about 3-4 inches from the floor.

I thought there was air still in the system but I don't see any air bubbles in the clear tube when bleeding. :confused:

How much free play is there in your pedal/pushrod to booster? The booster retains vacumn for several brake applications ( or one panic stop ) in case of engine failure...your system is reacting as it should. Have you adjusted your rear brakes?

There could be some adjustment needed to the rod length that connects your pedal to the booster/master. I haven't gotten that far yet in my project, but I would double check that you don't need to lengthen the rod a little bit.

Im using a disc/drum mc and the same power booster that was with the drum brakes.

Haven't touched the rear brakes, how is the brake pedal to rod adjusted?

Oh, my mistake. I was thinking you had changed the booster, or gone from a non-powerbrake setup to power like I am. If you didn't have to disconnect the rod for your project, then disregard what I said earlier.

Hey VNova,
not sure if this is what your doing, but when you bleed it, do it with the engine running, make sure your rear brake adjustment is good. Does the pedal feel spongy?

I've always bled the brake with the car off.

Would my prop valve be causing this low pedal?

I'll have to check the rear drums.

Does the rod stay the same on the booster?

I found this so I might check some things out.

http://www.mpbrakes.com/technical-support/troubleshooting-disc-drum-01.cfm

The only thing that it mentions about long pedal travel the master cylinder piston diameter.

I did a brake convertion on a 73 before and i had to pump the pedal for hours, i finally got the fluid to bleed out on the second day.

How is your brake performance?

When you upgrade to front disc brakes the caliper piston diameter is larger in diameter than the old wheel cylinders, so you displace more fluid and increase your pedal travel.

I had my combo valve mounted like this
http://i42.tinypic.com/2ibchlk.jpg
so i tried to mount it on its side and routed the left front brake line so its not looping up. I have the left wheel for the top and the right wheel for the bottom.

I moved the rear drum brake shoes out a bit. Pedal almost seems the same. Its like when you press the brake pedal you dont get a reaction soon enough. I have bled all wheels again, I get plenty of fluid through all wheels. Is there a way to tell if the rear brakes are adjusted properly? Right now they fit almost snug on the shoes.

Hmm if I put enough pressure on the pedal it will go to the floor. Im just about to take it to a shop and have them fix what ever is wrong cause I don't know.

Vnova,
Are your calipers (brackets) square with your roters? if they are not the pistons can be pushed back when pedal is released. using more stroke to square up.

There are 2 different length pushrods for the booster. Are you sure you have the right one for your master cylinder?

There are 2 different length pushrods for the booster. Are you sure you have the right one for your master cylinder?

Im using the same one that I used with drums. Is that okay?

I've noticed when I bleed the front calipers that I get some fluid leaking out of bleeder screw threads. Was thinking of get a pair of speed bleeders for the calipers maybe they would be better than bleeder screws? I will have to double check the flex hose and make sure its not leaking at the banjo bolt again.

Im using the same one that I used with drums. Is that okay?

That depends. See the info at the middle of this page:

http://www.pozziracing.com/brakes.htm

I'm with Jeff66. I've fought this issue on a couple cars. My caliper brackets weren't square with the rotors and my brake pedal did just as you described. You could plug the line going to your front brakes to see if this improves your pedal. I also have used framing squares on the rotor and bracket ears to see how far off the brackets are, it was obvious on mine. There have been other threads on this. See nova404's photobucket and you'll see my picture that resolved my issue.

http://i165.photobucket.com/albums/u55/nova404/P3140124.jpg

I'm gonna replace the bleeder screws with some speed bleeders but can't determine the size. I've used a 10mm wrench that fits. When I put my info on summit it only comes up with a 5/16 and 3/8. I thought it would be 10mm x 1.5. Are CPP calipers standard or metric?

They are considered a metric caliper.I believe they are S-10 style calipers so anything that fits an S-10 should work.

I ordered the bleeders and now thinking of replacing the front brake lines before I go and try bleeding the brakes again.

Any thoughts on this?
http://www.ss396.com/mm5/merchant.mvc?Screen=PROD&Store_Code=Nova&Product_Code=XKT-7001

I fixed a small leak at the prop valve and put speed bleeders on the calipers. With the bleeder screws that came with the calipers, they seemed to leak around the threads when bleeding the brakes. Decided to take the master cylinder off and try bench bleeding it again. There was only air coming from the rear reservoir. There is only a very small amount of travel now before the pedal gets tight, so im assuming that is normal since disc require more fluid. I got a front brake line kit from The Right Stuff detailing, so it looks like I will be bleeding the brakes again.

I bought a pair of speed bleeders for my rear drums but they won't screw all the way in. The guy at the auto parts store got a wheel cylinder for my make model and year and screwed 1 of the sb's in with no problems. Then when I try them on my drums they go in about half way and then its too tight to turn and if the brake pedal is pressed fluid shoots out the center. They are 5/16-24

:sleep:

i had a problem like this we i changed the master cylinder on a friends car.the pedal felt like it was going to the floor but it they did blead out OK.i found out that the problem was the master cylinder.the piston on the back if the MC had a hole that the rod would travel about 1" in the piston.the MC that had good pedal height only had a dimpple for the rod to stay centered.it took a long time to figure that one out i keep bleading the brakes and trying anything and it seemed like nothing worked.good luck maybe that could be your problem.