weird Brakes???

Well this is something that has been bugging me since I bought the cherokee 3 years ago. The problem is that there is no pressure/resistance in the brake pedal with the engine running until you hit the last bit of the pedal. You can feel drag in the brakes at the top of the pedal but not like you should. I've bled the system, had mechanics bleed it and they all say there's something weird about the brakes but they don't know what. The soft lines are new, as are the calipers and wheel cylinders. It did come with the Bendix ABS but the first owner had swapped it for regular power brakes. The pedal feels fine when the engine is off. So has anyone had this??? Any ideas??
Its a 1990 Cherokee Laredo, I6 AW4
Thanks Fletch

What does it feel like when the rear's are adjusted out?

8700XJS

adjusted out?
Well if you mean slack in the back then I'd say I notice they're not there. I'd have to say the pedal feel has nothing to do with pad or shoe adjustment.

I am going on the assumption that the obvious factors of brake adjustment, etc. have been addressed.

I'm going to guess it's one of two things, the second more likely:

1 - that when the previous owner converted from the ABS to normal brakes, someone didn't get the right adjustment, or that the booster and master cylinder aren't properly mated with the correct length pushrod.

2 - you have a bad master cylinder. If the rear portion is bad, it will behave just as you describe, sinking low but then giving you a good bit of front braking at the very bottom.

2.) sounds like the problem I had with my brakes and went through replacing the master cylinder and front braking units and it turned out that my wheel cylinders in the back were completely gone. Replace the cylinders and now I have brake pedal action