I got a 99 automatic with some problems I cant track down. Bought it, put an engine in it, and when i went to go through inspection it poped a brake line. No problem, fixed it bled it, cant get good pedal. its squishy but doesn't pump up. I'v got 5 Cherokees that can lock up the front, but this one hardly stops. Replaced the maser cylinder, no change. rebuilt the rear brakes completely, no change. I got good fluid to all 4 corners. What am I missing?

 

If you have ABS, that could be the problem. The ABS control unit has to be pressure bled to get all the air out of it. That requires applying pressurized fluid to the top of the master cylinder, then bleeding the brakes in the normal manner, being sure to let it run long enough to make sure there are no bubbles anywhere in the rear lines especially. The pedal in my WJ with ABS has always had a lot of travel before you get any response, but with the engine off has a hard pedal. My XJ is so tight all you have to do is "breath" on the pedal and you've got brakes. It doesn't have ABS either.

 

No, it does not have abs. Working on this thing is getting old. I have no idea what to do next.

 

Did you bleed the master cylinder before you put it on? Sometimes air can get trapped against the pistons inside the unit. If you did, I'm out of suggestions.

 

I pulled it off another jeep so it never really ran dry. I bled it anyway but It had no change at all. I'm loosing my mind over this thing. Brakes aren't this complicated.

 

Anybody have any ideas? I put on a brand new master bench bled and nothing. we just replaced the brake booster and nothing. Why can;t I fix these brakes?!?!

 

 

That kind of symptom can also be caused by a weak brake hose that expands when you step on the pedal, kind of like a brake system aneurysm.

 

I always start with the bleeder farthest away from the reservoir first and work my way towards the front. Have I been doing it wrong all these years or does it not matter?

 

I would suspect air in the system but it doesn't pump up like you would expect. If I ever figure it out I will update here.

 

I have found that if fluid wont flow out with gravity, something is wrong, like an internally collapsed rubber hose.

I do start with the closest one and work back, contrary to the accepted wisdom, also cracking any joins..brake fluid should run out

so like the other guy said, crack the bleeder, and a beer, if fluid doesnt **** out, work back

 

Well we vacuum bled it with a machine and still nothing. We got a pressure gauge and have around 1200 psi at the master cylinder but didn't have the adapters to test at the wheel. Also, with the new booster the rod is to short and the brake lights wont shut off. I don't have the original to compare to since it was a $60 core on the new one. I read somewhere that it's suppose to be adjustable but haven't figured that out yet. Anyone have any new ideas?

 

Definitely worth checking. I had weird feeling brakes for a couple of weeks on an old Fiat I had once, then they stopped working completely when the hose popped. Thank the Big Guy I was just pulling into a parking spot and not doing an emergency stop.