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?
Look under the vehicle at the rear area -there should be an 'equalizing" valve for the rear brakes - secure this valve in fully open position and try bleeding rear brakes
soft peddle feel maybe from a damaged brake master cylinder. this pressurizes the peddle, and if there is a leak in the cylinder it might feel soft or flop all the way to the floor.
Depends on if all four brakes were bled, if they were look at vacuum leaks or a faulty master cylinder as the culprit
you either have a bad master cylinder or you need to replace your brake pads if you hear a lot of squealing when you push down on the brake peddle in most cases that means you need to replace them unless you did recently then in most cases I would recommend bleeding the brakes there could be some air bubbles that are preventing proper pressure in your brake lines
If your brake peddle goes to the floor, you have lost brake fluid from your master cylinder in the engine compartment. Check your rubber brake hoses at each of your wheels, look for any signs of leaking brake fluid at your wheels, connections,lines, and master cylinder.
Without seeing it, I would say that the wheel cylinders may have rust/corrision in them preventing them from moving in their bores.That would explain why the pedal does not go to the floor when trying to bleed them. Crack the bleeders open and see of fluid comes out either one. IF it does, replace the wheel cylinders. IF not, there may be a restriction further up the line, collapsed brake hoses, master cylinder or a (proportioning?) valve problem.
Low brake fluid, drums/rotors in need of replacement, pads in need of replacement, air in the brake lines, worn master cylinder, brakes out of adjustment... all possible reasons.
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.
Try bleeding your brakes. If there is air in the system it can give a spongy feeling to your brake pedal and require you to pump your brakes and/or put your brake pedal to the floor.
This one is easy. Brake booster diaphragm is ruptured, causing a massive vacuum leak, which will cause the engine to run poorly when the brakes are applied. A loss vacuum assist will make it difficult to stop the vehicle.
Not really an answer, but another question... did you bleed the brakes after you changed them? I remember that is a critical step, NOT to be missed when working on the brakes. Hope this helps.
If you had your brakes worked on recently you need to have them bled. If not then you have a leak somewhere. Try listening to the master cylynder or the ABS resivoir and see if you can hear air coming from them. If not try bleeding your brakes and see if that helps.