Wondering if my ABS module is bad

[Coon killer]

I have replaced the master cylinder and brake booster on my 93 explorer and I have bled the brakes. I get a hard pedal when the engine is off but as soon as I turn it on I have no brakes and the pedal goes all the way to the floor. Is it the ABS module or could it be something else?

 

[Rick]

I just went through this with mine, literally yesterday.

I replaced the brake booster and all is well. The double diaphragm booster can do exactly what you describe when it goes bad.

 

[Roadrunner777]

ABS won't do this. Second the booster solution.

 

[Coon killer]

I just went through this with mine, literally yesterday.

I replaced the brake booster and all is well. The double diaphragm booster can do exactly what you describe when it goes bad.

I've replaced the brake booster but still, have no brakes while the engine is on.

 

[MrQ]

Is the adjuster rod set to the same length as the old booster

 

[Coon killer]

Is the adjuster rod set to the same length as the old booster

Yes.