I had a similar problem with my 51 1-ton with huck brakes, although only my rears locked up. It turned out that both of my rear brake return springs were broken or missing. The springs on my 1 ton were 3-piece, being the spring itself, and the spring hooks that slid in and out of the tightly coiled spring ends. Anyway I only needed two,but Napa ordered eight just to stock up. About half were delivered with the spring hooks having already fallen out of the tightly coiled spring ends.
Bottom line is, if you have the 3 piece spring it might have failed even if brand new.
