I've got a 95 Cherokee with abs. It's not drove a lot mostly just a spare vehicle but my g/f was driving it to work and a brake line busted on her and she continued to drive it and eventually ran the system dry of fluid. I got it fixed enough to get it home then Fixed the line and bled the brakes and nothing so I tryed bleeding the mc along with pretty much every connection throughout the system and still have no pedal. It feels stiff when it's off but eventually still goes to the floor but when I start it it's barely got any pressure at all. My 3 yr old could push the pedal to the floor. All I can find on here in previous threads is air in the lines. I'm pretty certain it's not the problem because I've went through nearly 3 bottles of fluid trying to fix it.

 

I bought a 90 with (Benix 9) ABS. It came with a rear wheel cylinder blown and the prop valve tripped, (I think). Rears had been dry a while. In the end what worked was applying vacuum to the rear bleeder, (I actually used a seal-a meal and a mason gar with a hole in the bottom for the line). THEN I disconnected the line on the Prop valve to the rears, and ran that to a quart of fluid. A major pain, there has to be a better way. Just vacuum didn't work. Trying to "pressure bleed"...not sure how good of a seal I got or how much pressure I applied, but didn't work.

Me thinks part of the "trick" is to get enough in the empty end, (rear in my case), to allow the proportioning valve to reset with high pressure on the petal. It won't reset without back-pressure, and it won't let fluid through if it's tripped. A catch 22.

I'm still scratching my head over that, but maybe info there might help...

Just changing, (or manually resetting) the prop valve, then pressure bleeding might work. ABS might have other places to bleed Btw. Accumulater?

 

Since you are doing all four, you need to follow a certain order. The farthest from the master cylinder first, so RR then LR then RF then LF.

If the brake line burst because it was old and rotting then other parts of the system may be in the same condition. Like Dflinstone mentioned, the wheel cylinders can and will pop randomly when they get old and dried out. They are like $12 a piece and easy to replace...might be worth a look.

 

The wheel cylinders and other stuff aren't in bad shape. If it is the proportion valve needs reset will it let fluid through to the wheels because I've got a lot of fluid coming through and can someone tell me how I can reset it.

 

Sounds like a bad master cylinder to me. Actually, Crazy is on the right track. You have a braking system with 20 year old components and one piece (hose) has already failed catastrophically. The rest of the system is right behind. For safety sake, please replace these parts:
Master cylinder, rear wheel cylinders, front calipers, the other hoses.
That should get the hydraulics solid and safe. Might as well do the pads and shoes too unless they are fairly fresh.
The proportioning valve will not cause the pedal to go soft or to the floor.