I can't get brakes on my 2001 dakota ,the pedal goes right to the floor with little brakes. I've changed the master cly. and no difference. I've bled the system.there is something wrong with the front brakes . Could it be the ABS control ?

You have air trapped in the braking system somewhere. Have you bled the system thoroughly at all four wheels?
Have you changed the front calipers recently. Many years ago, I helped a friend mount new calipers on his vehicle, and we put the new calipers on the wrong side -- right one on the left side and vice versa. In this configuration, the bleeder screw wound up on the lower portion of the caliper instead of at the top, where it needs to be to allow trapped air to come out. Just a thought.

I am wondering if you have to bleed the air out of your braking system. after repairs they should be bled to take the air out.

Brake line busted somewhere? Is the linkage to the master cylinder intact? Master cylinder might have been installed incorrectly.

Old, new, or remanufactured master cylinder?

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Hello Patricia,

Have you checked the master brake cylinder reservoir for brake fluid loss?

I don't suspect the master cylinder as you have replaced it... but am more suspect of a leaking brake line or fitting which should have
been discovered when you had the system bled.

The only time I ever had a rear brake problem with a 2500 series Chevrolet was due to seized rear brake caliper guide pins...as your calipers are also new that is not your problem.

If your brake pedal feels spongy and travels to the floor board you have air in the system, a brake fluid leak or a failure in the power steering system, such as a broken hose, broken power steering pump drive belt, or failed pump, would result in a loss of pressure to both the hydro-boost and steering.

Find more information here:

. Hydro Boost Power Assist Systems Operation Diagnosis and Repair

blead from the furthest point forward... so , if your master is on the firewall on the drivers side.. rear right , rear left , right front and then left front...

When you bleed the brakes are you starting with brake furthest from the master cylinder? Also was the master cylinder bench bled? If everything there is okay and you are not getting any air in fluid stream, you could try bleeding the brakes by having some one slowly pump the pedal till it is firm. Then have them let off open first bleeder valve and slowly depress to floor and hold there untol the valve is closed. repeat this at all bleeders. You may want to have car running to do this. Try this and let me know.

Did you bench bleed the master cyl. before installing it? then when you installed the new master, did you bleed all 4 points? If yes, then check all for points for leaking caliper/s and leaking wheel cylinder/s. If the van has ABS, check the valve body for a bleeder screw and see if air bleeds out of it. If you've checked everything twice and did everything right then your new master cyl. may be defective.

You need a scan tool to hold open the control valves in the ABS, air is trapped in it and you can't bleed the brakes until you have the ABS held open

change dump valve under master cylinder