No fluid at the rear brakes.

1986 regular cab long bed. What the truck said the master cylinder was replaced went to have the vehicle emission tested and rear brakes did not stop the wheels from turning. Opened up the bleeder valve and no fluid came out at all. Went to the master cylinder the front brake line opened it up all the way barely leaking out any fluid? Does this mean the master cylinder is bad?

I'm not sure "What the truck said" means.  Did you mean to say that the previous owner said that he'd replaced the master cylinder?

If so, then either the "new" one was dry in the rear chamber or defective.  Did you check that it had fluid?

Lol, voice to text didn't translate right. You're correct. Front and rear had fluid. Loosened up the rear line / closer to the firewall and it was leaking out like it should.

Brake petal feels fine too.

Maybe a bad rubber hose to the rear axle not letting fluid thru?
You started to find where you have fluid and were it stops keep going till you find where it stops.
Dave ----

I forgot to mention I repaired a part of the line that was crimped and either side had any fluid in it.

That was about where the filler neck is in the rail.

I second a possible swollen soft line.  

... I'm about to replace all of mine.  They go bad, it's normal.