1971 F250 Camper Special, 390/C6.

After discovering recently that I had a bad wheel cylinder on one of the rear wheels, I decided that since I had never really replaced much of the brake hardware or anything else in the rear, now would be the time to go through and do it all. So I did: New shoes on both sides, new hub seals, both wheel cylinders, all new hardware both sides. And the rear wheels are working great - but now the fronts are locked up!

Let me back up: Prior to any of the work I did on the truck, I did notice about a week ago that the front passenger wheel seemed kind of odd. Kinda felt like the truck was pulling to that side, maybe even locking up? I didn't think anything of it. I've previously replaced the pads in the front, and the hoses, but I think that's it.

Well, now after my success with the rears, somehow the front calipers are totally locked up. I jacked the truck up, took the wheels off and tried to spin the rotors and they're stuck. Ended up trying to relieve pressure in the calipers but both bleeder screws broke off in their respective calipers! (I think they might be the original calipers). Ended up finally removing the calipers completely on both sides, and of course, now both front wheels are free, of course.

With the lockup in the front, though, my mind started to drift towards the possibility of some kind of problem with the proportioning valve on the front crossmember - am I onto something here? Did fixing the rear somehow screw up the front? Or is just crazy coincidence that both front calipers went bad at the same time? Seems kinda crazy to me.

Any advice appreciated.

 

Did you try to disconnect the hose from the caliper and use a c clamp to push the caliper piston back in?
I went through this on my old dodge truck and I just replaced the calipers cuz the pistons were stuck.

 

Strangely enough, yes, both pistons were locked up, but the real cause of my problem was that I neglected to use synthetic brake grease on all the moving parts - used anti seize compund, which I thought was good enough. Apparently not. Everything was dry as a bone and stuck solid. Starting to put things back together now and suspect everything will be alright....