If the wheels are not locking up, no to the prop valve. Was there any glaze on the brake shoes? Is the problem exactly the same with the new drums? Are there any leaks such as axle seals, wheel cylenders?
One last thing. These vehicles are known for the shackle that attaches the leaf springs to the frame rust and break. Check them to make sure that isn't an issue. Normally, it is the rear shackle.
Let me know what you find.
Tuesday, October 19th, 2010 AT 9:36 PM