Stovebolt.com Forums The Shop Area Driveline Rear brakes lock up on 1947 Thriftmaster

After driving a short distance I feel a drag which becomes worse as I continue to drive. Eventually the rear wheels almost lockup. I found a leaking wheel cylinder which I replaced a bled system. I drove it a short distance and the drag is happening again. I check and bled system and it improves only to eventually lock up both wheels. Any advice is appreciated.

I'm assuming your truck is all stock. If not, disregard all of this. I had a similar problem with my 47 when I started working on the brakes although all 4 corners were dragging on mine. it turned out the relief port in the master cylinder was plugged so the brake fluid couldn't return to the master cylinder when you applied the brakes and got off the pedal. It would improve if you bled the brakes until you have enough pressure to lock them back up. Also make sure your pedal is adjusted properly and the brake return spring is installed so the cups uncover the relief port when you let off the brakes. Hope this helps!
Best regards,
Les

If the problem is isolated to only the rear wheels, check or replace the flex line between the frame and the rear end housing. Something is holding pressure in the rear wheel cylinders, and the flex line can collapse on the inside and restrict the fluid flow back to the master cylinder.
Jerry

Thanks for the.tip....I will check it out.

Thanks...I will check it out.