Jerm97xj

I am a newbie. I have a 97 xj. When I regeared and trussed the HP30 and 8.25 I decided it was time for a rear disc upgrade. I got the caliper brakets from a ZJ D35 at the junk yard. I installed new EVERYTHING (pads, rotors, calipers, hoses, rubbers, pins, center braided hose and both fronts with braided hoses). I also installed the prop valve and spring from the ZJ. My brakes seemed to be working fine until my first trip wheeling.

I found out my pedal goes to the floor when I am noise down or up, on the street they work great. I was thinking my Master cylinder was going bad so I replaced it with a stock one (it did not fix it). I then decided my rear axle was rotated enough the rear caliper bleeders were not the highest point anymore. So I jacked the rear end of the jeep way up and bled the rear brakes.

The problem seemed to be resolved in my yard but when i took it wheeling it came back. Saturday night we played in the mud a bit and my brakes were completly gone! As soon as i got on flat ground I pumped them a few times and the brakes work fine.

No red brake light ever and the fluid is full. I have bled the whole system several times and am running out of ideas. I as hopeing someone on here has seen this before and can give me the miracle answer. If you have any questions please ask. Thanks in advance for any help.

93XJLI

do the brakes feel right on the street? or do they feel "good enough for a jeep?"

you mounted the new rear brakes so that the bleeder screws are on the top of caliper, correct?

Gee oh Dee

Maybe still an air bubble somewhere...?

freegdr

master cyl low?

Jerm97xj

The brakes feel very good on the street. 33 mtrs are heavy and the my Jeep stops much better now that I converted the rear to discs.

The caliper bracket and calipers will only go on one way. I have a 6 degree shim built in to my rear leafs that turns the pinion up. I thought that may be the problem and thats why I jacked up the rear of the Jeep then bled the brakes.

Jerm97xj

Thats possible but unlikely. I have bled this thing several times. The only thing I have not tried yet is a power bleeder. Because my Jeep does not have abs, I did not think there was really any place for the air to hide being as there is no abs pump motor.

Jerm97xj

No. In fact I have tried to fill it up past the full line and it did not make a difference.

DieselD

Get the dual diaphragm brake booster. That might help.

If you brake pedal goes all the way to the floor and you get no brakes it sounds like there's a pocket of air on the system. Also did you switch out the prop valve on the rear? I can't recall but that might have to be done for the disc swap.

93XJLI

He has a 97...

If you're in a nose up/down position and you lose the pedal, what happens if you pump it without getting level?

freegdr

you did bleed rr lr rf lf correct

Jerm97xj

I get no pedal if i pump it. It just goes to the floor a bunch of times.

Yes, I always bleed the brake that is the farthest away from the master and work my way closer.

freegdr

may sound dumb try bleeding when on those angles yet ?

Jerm97xj

I did try that. I jacked the rear of the jeep up as far as my floor jack would go. I first used my vacuum pump and bled both sides then I had someone jump in and pump the pedal and bled it. Just for good measure.

freegdr

i mean when you loose the pedal block wheels put in park. ive never heard off anything this ****ed up

freegdr

when this issue arises do you have brakes or not?