Read as many brake posts as I could find, and still not definate on the cause.
79 4x4, already replaced master cylinder and both rear wheel cylinders. Adjusted rears. Ready to buy a new proportioning valve, but want to make sure that's the problem, as the front calipers work. Truck was sitting for 7 years, and I've read about that being the worst problem for brakes.
I was originally just going to replace the front calipers beacuse I figured they weren't functioning, and were pushing all the fluid to the rear. Then I realized that the front rotors are clean, shining and smooth, which they sure weren't when I was given the truck, so I know the front calipers work, and did a great job grinding the rust off of those rotors (better ways to clean them off, I know...)
Just wanted to find out some folks' opinions before I go and spend the $80 on a proportioning valve (http://www.inlinetube.com/Prop%20Valves/VFL101.htm), when I might have other problems...
Thanks folks!

 

Really Shiny rotors are BAD.

That means they are glazed and supply little braking power.

They need re-surfacing (NOT necessarily Turning or Removing material)

I would bet on the BPPV are the problem with the rears.

 

Sandpaper the rotors, or take them to a shop? Even supplying little braking power, it'll be better when I replace the PPV. I've made it over 400 miles with my brakes this bad, and now that I'm in Los Angeles, it's REALLY bad, because nobody here can drive worth a damn. I've been cut-off so many times, and come way too close to putting my brush guard through their expensive new Jap cars. I'll order the new PPV right now.
Thanks again Mil1ion.

 

The rotors need mic'd for thickness and/or warpage.

a fine emery cloth used with sanding block done in a circular motion may help.

http://www.inlinetube.com/pro_valves.htm

 

most of the time when that ppv goes bad you dont get any power to the rear. I think yours are locking up on hard stop because the drums are out of round.
When you were adjusting the rear did you notice that they would get tight then loose as you where spining the wheel?

 

Just ordered my valve through inlinetube. I'll see how that fixes things. I figure if I end up taking the rotors off to get machined, I'll be doing my u-joints at the same time, so it'll be a little bit before I have the downtime to get to all of that.
Thanks again.

 

yield2s, Yeah I did notice that. They would stick at points. Haven't thought about that in a while, so I forgot to mention it. That's more likely my problem...
Just spent $90 on a PPV, oh well, probably need a new one anyways...

 

Just consider yourself lucky ifyou can find the parts to do em yourself haha. Mine went out and ended up costing my $1,500 to have re-done there was only one parts supplier of my drums in the country and they were back east...that was a major part of the cost. Not only that I had to have everything done...new 4 piston calipers....new rotors...new bearings all the way around, wheel cylinders, shoes...oh and on top of it...after my new brakes were on...my carrier bearing b/w my two driveshafts went out! That was not a happy time...but now itll stop on a dime!

The guy who did the work for me at the local Sears was a fan of old Fords and had his in the parking lot...when I brought mine in he was all over it haha. He hadnt seen a Super Camper before and couldnt get over how big the drums were lol.

-Chris
(Sorry for the bit of a rant)

 

Just wanted to find out, can I get my drums machined if they're screwed up, or do I have to just get new ones?

 

You should be able to have them machined as long as they would be within spec after the work is done. That is assuming that they arent like out of round somehow.
-Chris

 

Replace your rubber hoses. They break down internally and collapse inside, restricting fluid flow to the calipers but appear to be fine on the outside.

 

new ones are about $30.00ea. and it'll be about 12 to have each drum turned plus half of a day or more of down time.

 

you can take your thinkin caps off guys this was the problem.

 

Right on Yield2s! I went and got my drums turned ($7.50 each), installed new seals, and bought some new shoes. No more lock ups. Just need to adjust the shoes, they're a little loose right now. Thanks again.

 

Hey check your pic message.