Rear brakes lock up, fronts don't seem to work

[LPGbody]

I just bought a 1995 K20 truck. Upon getting it (towed) home I noticed the smaller rear brake fluid reservoir was extremely low. I topped it up and bleed all four brakes just to be safe. However the pedal seems to do absolutely nothing until about halfway down the rear drums will immediately lock right up with a hair of pressure. I can't for the life of me to get the front brakes to lock up and the hood never dips down, I don't think the front brakes are even working.

I took the drums off and inspected the rear brakes, everything is dry and the lining looks brand new. I backed off the adjustment a little bit to see if anything would change and they still lock up.

I have not looked at the front yet but I lifted it up and spun the tires by hand and the brakes seem to stop me from spinning them. I noticed a bit of drag on the front passenger tire though. And that is where I am now.

 

[Radiohead]

Has the proportioning valve shifted?
If the hoses are original, it's possible that they have collapsed internally and at this age it's not a bad idea to change them out anyway.

 

[fast 99]

Wheel drag likely bad [stuck] caliper on that side. Rear reservoir low, did you pull back the wheel cylinder dust covers and check for leaks? If ok, pull the master and check for leak in back. The small rear brake fluid capacity it is possible at some point air entered.

Common problems might be a combination.

Low pedal, air, bad master, rear brake adjustment, ect.

No front brakes, stuck calipers, fluid restriction, air, bad master.

 

[Ricko1966]

Is the brake warning light on or off? Does it work?

 

[Drauka99]

If the hoses are original, it's possible that they have collapsed internally and at this age it's not a bad idea to change them out anyway.

/\ This was my first thought