The Stovebolt Site Forums The Parking Lot Tons 'o Fun Brand new wheel cylinders leaking - help!

I got my '49 GMC 253 1 ton truck last summer (this is my first old truck). I drove it twice and suddenly the brakes weren't doing much. I inspected and saw that one of the front brakes was leaking tons of fluid. I put it in the garage and started taking stuff apart. The front wheel cylinders were frozen. I took them both off and the pistons were unmovable. I ordered some new ones from Jim Carter, and got the shoes relined. I cleaned up and painted my drums, installed the new wheel cyclinders, along with new return springs and rubber hose.
I bled the master cylinder, and started to bleed the brakes, starting with the passenger rear. I pumped the brakes a to start bleeding and it seemed like I was using lots of fluid. I looked at the fronts and saw puddles under the drums. One side leaks much more than the other. If I work the drum shoe action by pulling with my hands, I notice one side of the cylinder's piston will follow, but the other one doesn't.
This side I had to adjust the shoes to go all the way in to get the drum on. They have a slight drag with the adjusters all the way down. Could having them all the way in possibly be locking up one of the pistons? The other side did not need to be down all the way, but pretty close. Did I get bad wheel cylinders? Please help! I'm excited to start driving it again!

I would find out how far out your drums might be turned to see if they are out of specs. I would also readjust the pads. I always turn mine out until the hub locks up completely, then back them of so I can barely hear the brakes dragging.

If the shoes are not set right, the pistons can push out too far. Same for the drums being turned out too far out of specs.

Thanks builder, I'll check to see if they are coming out too far.

I had a problem a couple years ago with some NOS wheel cylinders. It was the weekend and I couldn't get replacement cups so I took a real fine scotch brite and cleaned the outside of the cups a bit. They were old and had gotten hard. I got them scuffed very lightly and worked some brake fluid into them and put them back together. I was able to get things working. I DID order new cups and when I got them I put them in. My patch got the truck moveable and would stop. Just a temporary patch job but might get you by in a pinch.

Thanks for the advice Dan and Builder. I think I found my issue on one of the cylinders. I took the drum off, pulled the return spring off and started to work the pistons to make sure they were working. There is a pin hole in the casting of one cylinder, so when I work the pistons, fluid just squirts right out. So that one is no good. The other side look like it's leaking from the threads of the bleeder, but I'm not sure yet. The bleeder looks cross threaded in the hole. I'll do some more investigating on that side, but so far it looks like I have bad parts.

On my 49 Chevy 3800 drw I ordered the wheel cylinders the book said. The fronts were wrong and ordered two more of the REAR cylinders for the front. These weren't NOS but modern castings. In the process I got one cylinder that the bleeder wasn't drilled and tapped right and one that leaked no matter what cup I used. Just because it is anew part doesn't mean it can't be bad.

So true IbendCars. I hope the other one isn't bad. Jim Carter truck parts exchanged it no problem. I have the new one. Need to install it and see if it leaks.

More bad wheel cylinders. Bleeder screws wouldn't seal. Sent them back to Jim Carter and I got a set from my local NAPA that I put on and am in the process of bleeding. They look to be better quality. So far nothing is leaking (knock on wood).