Brake problems - Still have a long pedal

[Clark Griswald]

My brake pedal continues to have long travel. If you saw my earlier post

http://www.pelicanparts.com/ultimate/Forum3/HTML/010796.html

you will know that this started during a track visit that was especially hard on the brakes. I didn't sweat it too much because I planned a thorough brake upgrade anyway.

Well that upgrade is largely complete now. Here is the background on that:

http://www.pelicanparts.com/ultimate/Forum3/HTML/010796.html

As it stands right now, I have installed new pads, new rotors, rebuilt calipers, bled the brakes twice and have no air bubbles. I bedded in the pads.

And I still have a long pedal.

So now I am not sure what the problem is. The only thing things left are the master cylindre and soft brake lines.

The master cylinder was replaced about 6 months ago. I installed new teflon soft lines about 4 years ago. There are no visible leaks.

If I had rubber soft lines, I would assume that was the problem. But my understanding is that teflon lines never stretch, they just burst all at once.

Any brake experts want to speculate on this one?

Chuck Moreland '86 Cab - "Sparky", '77 Targa - "Sweet Pea"

[orbmedia]

Clark,

There was just a thread on this. If the master cylinder is holding pressure then it must be that the pistons have too much "freeplay". When you rebuilt the calipers you did not make them come out enough in the bores and now there is too much travel. Warren had discussed the proper procedure to correct this common problem.

[lsolon]

That's what fixed mine. Pull pads at one caliper at a time. Insert thin piece of wood and slowly pump pedal until the piston presses the wood up againts the rotor.Then press piston back into caliper and go to next. The wood should be the thickness of a pad that is almost worn to the metal. That's what I did after I recieived new calipers and had the same prob.

[Clark Griswald]

Problem solved.

I found the old post from Warren. Basically says it takes awhile for the new seals to adjust to the proper piston position.

I took the car for a drive and, with nobody behind me, repeatedly pumped and released the brakes while moving. This made the pistons go in and out. Didn't take too long.

Now the pedal height and travel are back to normal.

Thanks for the tips.