I recently replaced the front brake pads, rotors and calipers on my wife's 99 XJ. Everything went back together nicely. I bled the brake lines to get all the old fluid out of the system. The problem is that the brakes are now locked up. When the wheels are off the rotors turn fine. When I tried to take it for a test drive the front brakes wouldn't disengage. Got under there and double check everything. I even called the parts store to make sure I have the right parts. I'm out of ideas. Does anybody know what could be wrong?

 

Install the calipers right?

 

air lock in the master cylinder?

Try re-bleeding the brakes, right rear first then left rear then right frt and then left frt

 

wrong rotors? Did you compare them whie replacing them?

 

The calipers are right. I have a '98 Cherokee so I used that as a reference. I also checked the Haynes manual and a few write ups I found online. I'll try re-bleeding tomorrow. That's what the guy at the parts store said also. Thanks for the help.

 

The only things I can think of are:
Calipers installed on wrong sides and brake line kinked with tire on. Bleeder goes towards top.
Flex line degraded inside, blocking fluid flow.
Incorrect caliper/pad mounting, rubbing on wheel. >http://go.jeep-xj.info/HowtoFrontDisks.htm

 

Sounds like the wheels are hitting the calipers. I'd look very closely at that before taking the wheels off.

 

I took a good look at the back side of the wheel. The calipers aren't making contact wither wheels but it looks like the brake rotors are pressed up against dust shield. I called the parts store and they told me to check the build date. Depending on what month of the year my xj was made it may be considered a 2000. I never thought a brake job would be this complicated.

 

Dust shields are thin sheet metal, if the rotors are rubbing, just push them away from the rotors. Dust shields would not stop the rotors from turning, just produce a metal to metal squeal. Mounting the calipers on the wrong side (bleeders pointing down) will give you a soft mushy pedel when the brakes are applied. I might suspect sticking caliper pins (slider pins), if they are not moving freely in the holes, your calipiers would not release fully after making contact with the rotors.

 

Take the caliper and bracket off together. Make sure the caliper is floating properly on the pins. Take the pins out and add white lithium grease to them. If the pins are frozen, then the caliper could be contacting the rim.

 

You have the wrong rotors. There are two choices for 99 XJs, cast and composit. You had composit rotors and installed the cast rotors.

 

I think you hit on something bustedback. I think I had cast rotors and replaced them with composite rotors. The cast rotors have a greater diameter across the braking surface and the hub. Which explains why it looks like it is making contact with the dust shield behind it.

 

Correction: the diameter across the braking surface is the same.

 

I have to say "Thank you" to everyone who chimed in with advice. Turns out I had cast rotors and installed composite rotors. There is only s few mm. of difference between the two. The brakes are working great now.