Serious Brake Slider Pin Problem

DOC4444 · **Posted:** Fri Jul 02, 2010 7:43 pm

I started to install a new set of front ART rotors and PF C/M pads and found the left upper caliper slider pin was seized. It was a devil to extract. To my surprise, it has a rubber sleeve on it that is 3/4" long at the end. Never seen anything like it. The bottom pin is the usual type (constant diameter, straight steel). It slides fine in its bore. I can't imagine how the top pin could possibly slide freely in its bore without drilling it out to a larger diameter.

Anyone run into this? Did someone install an incorrect pin?

Thanks,

DOC

DOC4444 · **Posted:** Fri Jul 02, 2010 9:21 pm

I just bought a replacement slider pin kit at Advance auto parts. While nothing appears out of whack with the OEM pin, when compared to the new aftermarket pin, the rubber sleeve has a slightly larger OD than the aftermarket pin. The new one slides fine in the bore.

Anyone run into the rubber sleeve swelling and jamming in the bore?

Thanks,

DOC

BlackLibertyCRD · **Posted:** Sat Jul 03, 2010 4:38 am

can happen if the brakes get very hot

DOC4444 · **Posted:** Sat Jul 03, 2010 8:57 am

Thanks BL,

Any thoughts about leaving out the rubber sleeve? (I assume it's there for rattle suppression?)

Thanks,

DOC

LibertyCRD · **Posted:** Sat Jul 03, 2010 11:00 am

Interesting. There was a guy on jeepforum.com yesterday complaining that he couldn't get his top caliper slider pin out. Said he had tried everything.

DOC4444 · **Posted:** Sat Jul 03, 2010 11:28 am

Just reached a very good local mechanic. He indicated this a common problem. He strongly suggested assembling the slider WITHOUT the rubber sleeve and just packing the bore with high quality slider greese.

This should probably be posted for all KJ owners to see.

DOC

DOC4444 · **Posted:** Sat Jul 03, 2010 12:47 pm

Liberty,

I just looked up the thread you referenced on JeepForum. I'm not a member there. Looks like that guy could really use the tip to install w/o the rubber sleeves. Looks like he did everything "right" (right lube, etc) just like I did and he's cooked another set of brakes.

Could you post this tip for him there?

Thanks,

DOC

geordi · **Posted:** Sat Jul 03, 2010 4:42 pm

Wow, talk about good timing on this post! I finally have my CRD back from my sister, and she gave it back with the rear brakes grinding through the discs. Goody.

Can this problem cause the brakes to stick / drag and waste the mileage? Mine really feels heavy, like it won't coast at all. I'm seriously thinking there is a sticking caliper. Any ideas on how to identify which one?

DOC4444 · **Posted:** Sat Jul 03, 2010 7:25 pm

Geordi,

I have not done the rear brakes yet so I can't comment specifically. However, if you find stuck slider pins due to swollen rubber sleeves, go ahead and reinstall w/o the sleeves. Just fully pack with special slider grease to avoid rattles.

DOC

geordi · **Posted:** Sun Jul 04, 2010 12:30 am

I'm definitely going to have to do some investigation to see how these differ from other vehicles I've owned. All of the others have been either a bolt inside a metal tube, or just a solid bolt that threads into the caliper through the rear mount. I can't say I've ever used any "special grease" on any of them. Where do I get this grease, and is there a solid pin replacement option available instead? I don't like the idea of a space developing when the grease is pushed out of the way.

Leave it to Mopar to figure out a way to over-complicate a design that has only been working for 30+ years in every other car out there. :banghead:

DOC4444 · **Posted:** Sun Jul 04, 2010 1:35 pm

Geordi,

When you see the sliders, you will see that the rubber sleeves only slightly increase the OD and that it's no problem to delete the sleeves. "Slider pin grease" is available at any auto parts store.

DOC

geordi · **Posted:** Mon Jul 05, 2010 11:21 pm

Rear brakes are off now... Had to use a sledge and some abuse on the passenger side to get the rotor off. I don't know if I'm going to try and have that one turned, or just get a new one and turn the other. I'll take a close look at them in the daylight and see if it looks out of true now. The pads had worn slightly unevenly, and only just started eating into the rotor with one end of the pad backing. Looks like I got to it before too much damage was done. They should be able to be turned and saved. The E-brake still has about 1/8" of pad, which is OK since I never use the thing anyway. I might try to adjust the wheel a little to reduce any possible drag even further before reassembling.

Anyway... The design of the pins on the rear wasn't anything different from any other vehicle I have seen before - Unlock the bolt, pull it out of the steel bushing tube that has a rubber flex-cover on both ends, caliper ready to extract.

Do people normally disassemble that flex boot and pull the steel bushings too? Honestly, I have never messed with them on any vehicle unless I was replacing the caliper entirely. (only did that once, and the new one actually came assembled with the bushings already in it, ready to slap right on the car)

DOC4444 · **Posted:** Tue Jul 06, 2010 9:30 am

You should clean the slider pins and bores and repack with slider grease. You may be able to get away with reusing the slider boots, but they are cheap to replace and if they already have over 50K, you are pushing your luck. When they rip, water and dirt get in and jam the pins.

BTW, we had a new style rear caliper installed under warranty 18 months ago. I expect to be getting into those soon and will see if they use pins with rubber sleeves as the fronts do on the top side.

DOC

StanCRD · **Posted:** Thu Jul 08, 2010 10:10 pm

In my past life as a mechanic, I never saw caliper sliders stuck due to the rubber expanding. In every case it was due to rust on the pin or in the caliper or a combination of both. Don't use wheel bearing grease or antisieze on any of those parts, it will make the rubber and pin stick if it gets cold where you are. I only used synthetic caliper slide grease to lube.
You only need to replace the pin if it has been damaged by rust. I just checked mine and they slide perfectly but my rear pads did not wear evenly anyway. One thing that did happen when I checked mnie is that my parking brake shoes fell apart and the rivets that hold the backing plate down broke due to corrosion (on a low mileage 2006 !) I have to say this is the worst design I have ever seen. To fix it properly you need to pull the axles !.
Good luck with the caliper pins..

geordi · **Posted:** Fri Jul 09, 2010 2:07 am

The pins slid around smoothly, both before and after. I used the same synthetic goop on them that you did, so they should continue to be fine. No sign of any rubber components on the slides, other than the boots themselves which also were fine. I couldn't figure out how to get them out without pulling on them, and I wasn't about to do that and risk making them NOT fine anymore... So they will just have to survive in place.

Honestly, for the amount of miles my family puts on our vehicles, I seriously have never messed with pulling the pins and greasing them before, or have ever changed those pin boots. I don't know how we've avoided the problems mentioned in this thread, but I'm OK with that.

As for the rotors, I ended up just putting them back on as-is for the moment. I don't have the cash to spend on replacing them, and they were still within diameter spec, but the wuss at Midas just glanced at them and said they were out of spec and couldn't be turned. Whatever dude. :roll:

They were just starting to get chewed by the end of the pad backing, and the new pads have a lifetime warranty from Autozone. So if they get eaten in a year or whatever, I get a new set for free instead of $18. I'm ok with that too. $18 is a lot better than $80 when you aren't working.

e_poirier2004 · **Posted:** Fri Jul 09, 2010 4:51 pm

The rubber sleeve swell and once removed, you can't put it back in. I just went to the autopart store and got a pin kit. I replaced the pin with the sleeve for the other pin without the sleeve. I've been running like that for 2 yrs with no problems.

fatweasel · **Posted:** Sun Mar 11, 2012 9:29 am

Changed front rotors/pads this weekend and stumbled across the rubber sleeve on the slider issue. Will attempt to post a picture later.

I found that the rubber sleeve pin did not allow the caliper to move evenly. the result was that the pads were much thinner on the rear edge than the front edge and the rotors were trashed.

I pulled out the pins and pressed them back in with a vise. They seem to be floating much better now.

DOC4444 · **Posted:** Sun Mar 11, 2012 11:43 am

I can't for the life of me imagine what you would use a press for in relation to installing the caliper slider pins.

DOC

EAB · **Joined:** Tue Sep 06, 2011 9:39 pm **Posts:** 141

StanCRD wrote:

In my past life as a mechanic, I never saw caliper sliders stuck due to the rubber expanding. In every case it was due to rust on the pin or in the caliper or a combination of both. Don't use wheel bearing grease or antisieze on any of those parts, it will make the rubber and pin stick if it gets cold where you are. I only used synthetic caliper slide grease to lube.
You only need to replace the pin if it has been damaged by rust

I second the above (over 20 yrs as mechanic here).
Make sure the pin and pin bore are clean and use the correct lube and they slide easily. Honda uses this rubber sleeve setup also, so you know it works

DOC4444 · **Posted:** Sun Mar 11, 2012 7:30 pm

Hondas may not have a problem with their slider pin rubber sleeves expanding and jamming the calipers, but Jeep KJs do. It's just a fact. There is no difference between the gas and diesel KJs, in this regard. The local Jeep shop I checked with in my area has been seeing this for years on scores of Libertys and has been successfully addressing it by simply deleting the sleeves.

BTW, they have never seen a problem with rattling after leaving out the sleeves. We have over 70,000 miles on ours since deleting the sleeves. No rattles and the calipers are still nice and free.

So, there seems to be no downside to this mod. However, there is to leaving the sleeves in. By the time you realize your pins have jammed, you have trashed a rotor or two, plus the pads.

BTW, the other "local knowledge" regarding KJ brakes is if you have a hard time retracting the pistons when replacing pads, it's time for rebuilt calipers. Apparently, nobody has come up with stainless steel pistons, yet. The composite ones eventually jam and do not retract properly.

Also, the flexible brake lines can collapse internally and keep the pistons from retracting, causing the brakes to drag or even fully lock up. (Happened to us.) This is hard to diagnose because it goes away when the brakes cool down.

DOC

Serious Brake Slider Pin Problem

Who is online