Be carefule with those rear brake calipers. I heard what sounded like brakes grinding so I swapped out my front rotors and pads Sunday (76k miles on an '07). This wasn't the cause of the noise it was the rear brakes. I ordered the brakes and rotors for the rear yesterday and planned to do them this weekend. Last night I was almost home from work when I lost brake system pressure. Luckily mines a manual and those aren't too hard to slow down. When I finally got it home I climbed under the back and found that my driver's side rear was fine but the passenger side rotor was shot and brake fluid was everywhere. Went by the dealership and picked up a new caliper at lunch today for $42.

 

The traction control can go nuts if something it out of whack. I found 2 glowing rotors after a drive one day. It traced back to one bad rear caliper. To compensate for thd bad rear caliper it put the brake on in the front. This was at 16k miles. No lights on the dash. That tank was down a couple mpg's.

Overall the braking system on JKs seems to be a crapshoot. There are tons of people who have had to replace brakes/calipers/rotors before 20k.

 

Thought I'd drag this up and add to it a little bit. '08 that I have owned since new, bought Febuary of '09, and has 52k miles on it now.

Last month I had the front passengers side caliper lock up on me. I thought it came on rather quickly, but it turns out it must have been doing it for awhile. I had been fighting a front wheel shimmy for about a year that I could not manage to clear up. I had finally decided that it was just due to my steel wheels (that have thrown a couple of weights) and the half worn BFG KM's I'm running. Anyway, last month I went for some Saturday morning errands with the top and doors off and 15min down the road, the Jeep was driving horribly. Bad vibes at anything over 40mph and every time I hit the brakes it was pulling hard to the right. At that point, I got off the highway and onto surface streets to milk it home. By the time I got there, it was almost undriveable. It was literally ripping the steering wheel out of my hand when applying the brakes and I had to give it gas to maintain speed going down hill. By this time, I could smell the hot brakes and I knew right away I had a seized caliper. When I got it home, the front passenger wheel was so hot that I couldn't touch it. After a search here, it seemed that seized calipers are becoming common place on the JK's. So as a bit of a preventative thing I ended up buying both front rebuilt calipers. Everything went pretty smoothly. The pads were worn unevenly, but not completely trashed. I put new pads on, and I managed to save the rotor. Fast forward a few days.......all of the front end shimmy is now gone, and the Jeep drives better than it has in years.

Then, after a few days of driving with the new front calipers, I got to thinking that it felt like it was still having some issues. When I let off the gas, I felt like it was slowing down faster than it should. I decided at that point to go ahead and check out the rear calipers as well. I had assumed they were fine due to just replacing the pads on the rear last March, and everything looked good at that point. It turns out my passenger side rear caliper was seized now as well. It didn't seem to be as bad as the front was (I could touch the wheel, but it was hot), but the brand new pads I put on earlier this year were completely trashed and so was the rotor. I ordered new pads, new rotors, and 2 more rebuilt calipers. Removing the OEM rotors turned out to be an absolute PITA. I backed the emergency brake adjusters all the way off and there was still too much rust build up inside the hub to remove the rotors. I had to beat the living shit out them for about an hour a piece to finally get them over the emergency brake shoes. I hope the aftermarket rotors I put on hold up better than the OEM ones. At this point, I ran out of light and good weather over the weekend and hope to get everything reassembled tonight.

Now to another tidbit. I'm beginning to think Jeep must have used old or contaminated fluid in this thing from the factory. I removed the bleeder screws from the old front calipers last night and the orifice was completely contaminated with rust. I can only imagine what the inside of the caliper and piston look like. Of all the vehicles I've ever worked on, I have never seen something as bad as this......especially on a 4yr old vehicle with 50k miles on it. I was quick about swapping the old calipers with the new, so bleeding the system was easy and only took a couple of brake pumps to get the air out, but now I'm concerned about the fluid. Once I get the new rear calipers on tonight I plan to do a full flush of the whole system to try and get all of that old fluid out of there and hopefully keep these new ones alive and well for longer than another 4yrs and 50k miles.

moral of the story......I think its in everyones best interest to flush their brake systems as a preventative measure. I'll see if I can remember to snap some pics and post them up when I'm working on it tonight.

 

I agree. I replaced both front and rear pads/rotors and luckily my calipers seem to be operating smoothly. I decided to flush out the old brake fluid with fresh and I couldn't believe how much crap was floating around. I ended up removing the reservoir and flushing it clean because it was so bad.

Sent from my SGH-I337M

 

I snapped some pics of that front caliper orifice last night. Then I decided to disassemble the caliper to see if there was corrosion inside as well. It actually looked a lot better inside than I was expecting. You can see the ring of corrosion around the piston, but the inside bore of the caliper itself is pretty clean.

First up, the rusty orifice after the bleeder nipple was removed. The bleeder nipple was equally corroded.


here is the ring of corrosion around the piston. I believe this is the actual cause of the piston not being able to retract properly


A good shot of the caliper seal where it meets the piston. This seal was a little beat up (I'm assuming from the piston corrosion). The corrosion around the lip had crept its way around the lip of the caliper and had deformed the seal at a few places.


The internal bore of the caliper looked pretty good


After having a look at this, reassembling the rear brakes last night, and flushing the system with new brake fluid........I have come up with a few conclusions.....
1. The calipers were never bled properly from the factory. That is the only way I can figure that the orifice was that rusted, while the internal bore still looked good. There must have been a small air pocket there that was collecting moisture.
2. The brake fluid installed from the factory was either old, contaminated, or junk fluid. What I bled out of the system last night was disgusting. It was VERY dark brown with a lot of cloudy sediment floating around in it. I may do another complete flush in a couple of weeks just to make sure I got it all out of there.
3. I am once again disappointed in the overall quality of my Jeep. I know its a Jeep, and I expected to turn wrenches on it........BUT wow, this thing is built like a pile of junk. This is at least the 4th weekend of the year that I have wasted trying something that I have never had to worry about on any other vehicle I've owned. I'm constantly amazed at the amount of rust, corrosion, and poorly designed things I find on this Jeep. Its a damn shame that it is so much fun to drive when its not broken.

 

I had to replace both front calipers around 20k miles do to them seizing, they went out within 500 miles of each other.