If bleeding rears and bleeder is open and peddle wont go to the floor try a front bleeder to see if you get results. what did you do to have to bleed them?

No!...Go and see your DR

The master cylinder MUST be bleed first before any bleeding at the wheels can occur. if you do not do this, you will be bleeding for hours.

I would suspect the Master Cylinder if defective.

I had the same problem with my 1978. I replaced the combination valve and it solved the problem after bleeding.

1. Venous bleeding (bleeding from the veins). 2. Arterial bleeding (bleeding from the arteries). 3. Capillary bleeding.