Chevy M1008 (K30) brake problem

[sht2kll]

Howdy All: A few weeks ago, I noticed My rear brake/brakes would drag after trying to accelerate from a stop. I was told to check fro a leaking seal. A week later while coming to a stop, My brake pedal went to the floor. upon nspection, I found that the right rear brake line ruptured. I fgured it was time to rebuild the brakes and decided to do a disc conversion to it. While installing discs, the left wheel seal was leaking and was a gummy mess. I figured this was my dragging brake. This truck is rusty as it spent a majority of it's military career in New Hampshire. I changed the rt. and lt. lines, the hose and the little "C" shaped line from the proportioning valve. Bled and purged all the old DOT 5 with fresh stuff. Brakes worked well. All is good..... so I thought Last week while at a stop, the brake pedal felt a little squishy. I pushed hard on the pedal and when I let off the brake LIGHT came on, push on pedal it goes out. I pushed on the accelerator and truck will not move. The rear brakes locked up. I floor it and am able to overcome the brakes and get it to the side of the road. I open the left caliper bleeder screw and a jet of fluid squirts out. the truck was fine and I drove it without a problem till this morning. I go to take off from work and the brakes are dragging bad, this time I open the rt. bleeder and... fluid. I figure it is the proportioning valve. does anybody know where I can get one? I have been searching junk yards, military and civilian. GM discontinued them and the parts stores do not list them either. Has anybody replaced this with an aftermarket one with success? Any ideas or info would be a huge help. Sorry for the loooong post. Tom

[wpdozer]

If you use the parking brake, the cables may be bound up, I did a quick search for a rear lever type proportioning valve after reading your post, and found nothing. Plenty of front valves though. It was of interest to me as I have an M1031. You may have to have it rebuilt as you would a wheel cyl. Search CUCV parts, you may find something. Check out Steel soldiers military web site, those guys hoard hard to find parts like that to keep their trucks alive. There are also many Steel Soldiers members here at The Desel page. Even though it is not a military spicific part, and just a stock K30 valve, you may find it there.