If you changed the M/C you need to bleed the entire system. Did you bench bleed the M/C?

 

yes I blead the master cyl b4 putting it on. After it was put on I have had to drive the truck with just the rear brakes (front was blocked off) and had good pedal.

If my problem was just air in the lines wouldnt it still hold peddle once pressure was built up? We can get pressure built up but it bleads off real quick.

 

bad caliper? fluid could be leaking inside the rubber boot around the piston on one if them?

 

thats going to be my next step, I bleed the front and back again last night and still the same result.

 

well I just replaced the callipers, same old crap, builds pressure without the truck running and then as soon as you start it up it will blead off as fast as you build it. I got the front breaks blead and reblead the back without the truck running and had good pressure at all wheels. As soon as my wife fired the truck up it would loose pressure. Im about to pull my hair out........ Going to try to change the wheel cylenders tomorrow and see what that does

 

That tells me something is wrong with the booster system...

 

well it appears to be a issue with the abs computer or something. I unplugged the thing that looks like a dist. box that rights below the dist. box. The brake and abs light are on but the breaks work just fine now. I am going to take it into dodge in the morning and see what they can figure out. thanks for the input

 

Get ready to be pissed......that thing will cost you big bucks. I'd look for a used controller or just pull the bulbs and go without the ABS.

 

thats what I figured :/