Hey, guys!

Need some help here. I've got a 1986 F250 plow truck that I'm having a heck of a time with. The other day I finally got around to replacing a rusted out section of brake line (the section that connects to the proportion valve) and got them working again. The brake light never ended up going off, but after bleeding I had a good amount of pressure in the pedal and the brakes were responsive, so I didn't think anything of it.

When I went to take it for a plow today (first time since replacing the brakes, other than rocking it back and forth in the barn to test them), the rear right wheel locked up on me while in drive and neutral but not in reverse. Bled the brakes out from that valve and it was still locked up in drive. Ended up having a neighbor tow me off my driveway.

I suspect this has something to do with the proportion valve, but I'm a mediocre mechanic at best so I can't say what.

Any ideas?

Appreciate your advice in advance.

 

I did check to make sure the e-brake isn't engaged, yes! I was chatting with a friend this evening and he suggested that a pin in the e-brake linkage could have come out. I'll be checking that tomorrow.

Hope it's not a warped drum, but I'll look at that next.

Appreciate it!