I have a 04 dodge 1500 Rumble Bee. I replaced 3 calipers because unable to remove bleeder screw. I bled the lines several times and the pedal still goes to the floor and there are no leaks. When you pump on the brake pedal it gets rock hard as long you apply pressure. When taking your foot off within seconds the pedal goes to the floor. Is it the master cylinder or something else? Someone suggested putting a scanner on the ABS, bleed the lines with the engine running. I'd appreciate any input.
Thanks,

 

Is that with the engine running???

 

Did you install the brake caliper with the bleeder screw facing up? There is a left and right side design for calipers and they are not interchangeable.
For pumping brakes during bleed, a best practice is to put a board on the floor under the brake pedal so you don't push the brake plunger too far and allow air in.
I'd first assume you have air in the lines. You will likely need a pressurized brake bleeder to get it out. ABS bleed is good idea in case there is air in the brake module.

 

You can bleed it the old fashioned way like I still do:
get a second person to help you. Have them sit in the cab and press the peddle a few times and hold it. While they are holding it. You go to a caliper and let the pressure off while they push it to the floor. Once they hit the floor with the peddle you tighten the screw back up and they pump it 3 times and hold it again and you go on to the next caliper and do the same as the first. Do this all they way around until you get no air from any of them and you should be good

been doing it like this for years and hasn’t failed me yet

 

If a bleed nipple won't budge, you can bleed by cracking the brake line where it enters the caliper using the two person method. Anyway, water under the bridge.

The two person method is great. I do one person method by putting a clear hose on the bleed screw (must fit tight) and submerging the other end in a bottle of used brake fluid (usually the old fluid I suck out of the reservoir before I start bleeding). I pump till the line has no air bubbles in it, then move to next, in proper sequence. Now for the ABS, a wet road or dirt/gravel road and lock the brakes up a few times. I look forward to that part.

 

Don't get it. The original caliper bleeder screw doesn't face upward. The new ones face to the rear.
How can I test the master cylinder without buying a new one. It's a money pit now.
Before this I installed a fuel pump, and didn't get out of my driveway when
a brake line broke. Replaced all new brake lines. I never ran into this, after bleeding the lines the pedal
goes to the floor.

 

You still have air in there somewhere. Need to do the two-person bleeding method to shock the air out.

 

When the engine is running, pump the brakes up and hold. If your master cylinder is bad, it will sink to the floor eventually. If the bleeder screw breaks off, you need to rebuild or replace the caliper. One person can bleed with a length of hose (I use clear to watch for bubbles), an empty bottle (I save maple syrup bottles for the clear glass and handle to wire it in place). Make sure the hose goes up into a loop then drops. Any bubbles will float to the top. Make sure the bleeders are at the top. Otherwise you will never get the air out.

 

Can you post a picture of your brake set up? There may be a misunderstanding about the name of caliper parts.

 

The bleeder must be at the TOP of the caliper. Doesn't matter where it exits fluid. You can easily put them on the wrong side, which results in the bleeder screw at the bottom of the caliper. You can "bench bleed" the master cylinder, see youtube for examples - probably a half million videos showing that.