Front brake idea

[James72]

If your rears are locking up, I'd take a closer look at the rear brakes. If the inside of your rear tires are wet, could be diff oil from a leaky axle seal, which makes brake shoes grabby (especially when cold). Another common one I've run into is the rear brake proportioning valve, there is a spring loaded ball check valve to the rear brakes, the harder you hit the brake pedal it allows LESS brake fluid flow to the rears to avoid lockup under hard braking (down to nearly 0% in extream braking) If it's malfunctioning or if your fluid is contaminated (sludgy) it can cause intermintent rear lockup aswell (proportioning valves are usually cheep).
Good luck.

[James72]

I'm also going trough my brakes ('72 F250), if you do get into the rears and yours is a 250 it's a good idea to do the wheel seals aswell because of the "inboard" drums. Another thing that really helps is to get a spring and automatic adjuster kit, they are cheep and and keep those old drums in check. If your old auto adjusters (star wheels) are going to be reused, be sure to clean them and use a little "never seize" compound inside, on the threads, and on the ends where it contacts the pads (new or old) or they will seize in weeks and not adjust for you. When drums are working properly it's hard to tell the difference over discs, that's my opinion anyway.
James