rear brakes won't bleed

Make sure your stinking compensating ports are working! If your pushrod is too long, preventing the ports from opening on the back stroke, lol, yur gonna be there for a very very long time. Then;
Make sure your M/C is plumbed correctly;
If a Mopar unit; the front reservoir goes to the rear brakes via the P-valve section of the Combination valve, which should be to the bottom.
If you plumb it backwards with discs you won't get enough pedal travel to push fluid to the back, and the fluid will just shuttle back and forth in the line. If you do manage to get it working like this, the car will stop just fine, at modest pedal pressure. But with more pedal pressure, and the fronts now proportioned, the back brakes will lock up and there goes your steering. hang on an enjoy the ride, lol.
Post #7 will definitely help.
If you think yur short of pedal travel for purposes of bleeding, simply disconnect the line to the front brakes at the M/C, and reinstall the bench-bleeder hose, then bury it in the reservoir, to prevent splash. now try it.