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Trials and Tribulations of Rebuilding the Fixed Caliper Kelsey-Hayes 8 piston system on a '70 Duster,
by John Weyrick.

First, the problem happened. The front brakes wouldn't release, car could hardly move. Second step is to hang around the Mighty Mopar cruise and ask everybody what to do. The consensus was to use a newer disc system, as these calipers are $135 each, rebuilt from Central Auto parts, the only place in my hometown of Orlando that I found them. They said this was hard to do, and it took me a week to rebuild the one barrel Holley that they said was easy. But besides the money, I'd like to keep her original, and let me try.

With a Haynes manual to follow, off come both calipers to the kitchen floor. Doing one at a time, the caliper splits in half, exposing four little pistons. Following instructions, use an air compressor, and pop out the pistons. Wrong! Use the air and one of the two pistons in each side pop out, the second won't because of the big hole where it was. OK, then just put one piston back in, and apply air again.

Let me tell, you I was using 80 lbs on a little air jet, and without the ability to thread it into the hole, I wasn't strong enough to just hold it there.

Brakes

So I used a C clamp to put piston that had come out back into its bore and hold it there, (with some wood to keep from scratching the metal), and the other piston pops out. But then the piston that I had re-inserted was back in and wouldn't come out by hand. Back and forth...the anti-seize was the cure, coat the piston, and it would come out more easily. Except for one. The 80 lbs was not enough for one stuck piston, I tried several ways to get a good connection to the air jet, but the pressure would push me away. OK then, for one piston, with a C clamp holding in the other, I connected back up to the car to use the hydraulic pressure to push it out.

Don't forget to aim into a rag, pillow or something soft or you'll damage the piston. Upon disassembly, one piston had been reassembled with 2 big dings in the seal collar, so back to the Auto Parts to buy a 1 5/8" piston from Wagner. Oh no, not so fast. They had the right part number on the box, but the pistons inside were 1 7/8, way too big. Every one at the downtown store and the folks at their other two stores were wrong. Special ordered it they said and would come in a few days. It's always a good thing to have another vehicle available when working on your old car. When it comes to removing the seals, I found wooden toothpicks to be ideal.

Demon

So the book says to install in reverse order, each cylinder has an oil seal down in the bore, coat it with brake fluid and install. Insert piston being careful to get it straight, then put the dust boot on. No again. This does not work, no way no how. I don't care if the book says to re-install in reverse order, it won't seat. After the seal, put the dust boot on, fitting it in correctly, then gently open it up to put piston into dust boot, then line it up to bore, gently install, using wood block to protect metal.

The dust cover goes together easily then. My discs had been turned last brake job according to original owner, so I didn't even take them off. Reassemble, torque the big bolts to 70-80lbs, the smaller backing plate mounting to 50-80, and bleed the system a lot. Once you have completed all these steps, your old Kelsey-Hayes 8 piston system will stop on a dime and give give you a nickels worth change.

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