The Stovebolt Site Forums The Shop Area Driveline Huck Brake question

My 52 1 Ton (or it may be a chopped down, re registered 1.5 Ton based on some oddities), has pedal issues. It has been sitting for a long time so the front cylinders that I replaced were clogged up and I replaced the rear cylinders recently. The rears were the larger cylinders that used the round discs with the knobs. One of which i replaced so I could adjust the brake. I have also rebuilt the master cylinder. We used a brake bleeding device that used compressed air to force brake fluid through the master cylinder through the lines to the cylinders. The brakes have been adjusted out to the point of a slight drag on all the wheels.

The problem is, to get a decent pedal I still have to pump the pedal, typically a sign of air in the lines. I have not found any evidence of leakage at any point in the system, and with the solid stream of fluid coming out of the bleeders, I don't think I have air in the lines. Is there something in the master cylinder that could cause this or not enough adjustment on the drag?

Anyone with any thoughts?

You need to adjust the brakes up till you get a heavy drag. Then back them up a little till they turn without a heavy drag. You will still have some drag but they will free up as the shoes were into the drums.
George

Another thing that it took me a couple years to figure out with Huck brakes is you have to adjust both shoes separately, unlike Bendix brakes. Run one shoe out until it drags, then back it off and do the other side the same way. I used to have to pump my brakes also, with a good strong pedal after pumping. It just took too much fluid movement to get the shoes in contact with the drums, requiring the extra pump.

Yup as soon as mine wear a bit and get out of adjustment the pedal is noticeably lower but i dont let it get to the point where i need to pump it. I did however the first time around when i built it with the dual master and it was confusing at first but once I finally got the adjustment dialed in i was “ahhhh this is how its supposed to be”. Pedal went from 1.5” off floor to like only 1.5” total movement. Stopped great too haha. Now i just keep up on it.

Thanks for all the comments. Another thing I had forgotten about is that a rear backing plate is bent, due to pulling off the brake drum efforts. If it bent one way it will bend the other and then I can get back to the adjusting process.

Just another thought on the bleeding process using the power bleeder ... Did you stop bleeding once you got a steady stream? On my 1-ton Hucks, I found that after the initial steady stream, I would get another few air bubbles after a few seconds of the steady stream. I mention this just in case you didn't know to keep bleeding for awhile after you hit the steady stream. And yes, you will go through a lot of brake fluid. But I have rock firm brakes as soon as my foot touches the pedal. Everytime. I took my truck out Sunday for the first time since last fall (for a real drive) and the brakes were right there.

Follow all the advice above for adjusting. But I wonder if you are not yet done bleeding ... ?

Make sure the master is returning ALL the way or it will not let it get fluid from the master how it should.

Thanks John and Barnfind, I am going to resume this journey again this week. The master cylinder is the only thing that has not been replaced, only honed and rebuilt. This problem does not have just one cause in all likelihood.