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Jeep Commander XK (2006 - 2010) Technical forum for the full-size Jeep Commander.

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Old June 23rd, 2018, 04:46
WB9YZU WB9YZU is offline
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Location: Madison, WI
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Front Brake info

I had the pleasure of working on my front brakes yesterday. We had taken the boat out and noticed that under heavy braking the front left made a horrible grinding sound. I parked it a couple of days on the grass on the side of the house. When I went o move it, it made this shuffling sound, and it again sounded front left.

Brake service time!

I started with trying to figure out what the shuffling sound was. It sounded familiar from my XJ days. It was a rusty dust shield that had flaked off some rust due to the heavy amount of moisture we've gotten lately. Easy fix: Wire brush, rust converter, paint - done.
To get to the shield, I removed:
The Caliper (14mm)
The Caliper Bracket (21mm)
The Disc (it's probably fallen off by now)

I looked at the pads, they were not wore out, but the inner was much thinner than the outer, so I checked the caliper guide pins on the caliper bracket. Sure enough, the lower one would not move and was completely rusted in.

I think a word on Commander brake architecture would help here:
When the caliper receives fluid pressure it pushes the bores out to push the pads onto the disc. Most OEM brake systems have pistons on only one side. To make sure it applies force equally, the caliper "floats" over the pads and puts the same amount of force on the inner and outer pad.

If the pads wear unevenly, chances are the guide pins are not free to slide in and out.

*** Maintenance Note ***
When performing front brake service, at the very least, verify that the caliper guides move in their bores.
If you want to be preventive, pull the guides from their bores (yup, just pull them out!). Re-grease them with silicone grease, and push them back in. If you damage a boot - well they are cheap and easy to replace.

On XJs the caliper bracket is part of the knuckle assembly (Except the AMC models, which had a replaceable bracket).
On a XK the bracket is removable and available as a part, as are the guide pins and boots for the pins. These are apparently high in demand as the O'Reily stores in my area had the parts in stock.

To replace a rusted in guide, you will need:
A Caliper Bracket.
A Boot/bushing Kit.
A Guide Pin Kit.

Assembly of the caliper bracket:
Get some silicone grease if your bracket did not come with one.
Over each bore hole, install a boot.
Push a bushing over each guide pin (pointy end).
Apply grease to the bushing and guide pin and push it through the end of the boot into the bore.

On mine, I did the drivers side first as it was the big issue. When I slid over the the pass side and found I had the same issue. The OEM pins fit the reman bracket, so with 2 good OEM pins, I had enough to populate a new bracket. My job took 2 Brackets, a Boot Kit, and a Guide Pin kit.

Good Luck!!

Last edited by WB9YZU; June 23rd, 2018 at 04:53. Reason: Spelling
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Old November 22nd, 2018, 20:56
WB9YZU WB9YZU is offline
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Location: Madison, WI
Posts: 6,941
Re: Front Brake info

A quick update:
Once again, the brakes are chattering. When I was finally able to remove the caliper, I found that the pins had, once again, frozen in their bores.

This time I knew it couldn't be rust, it had to be something else.
After alot of messing around with with a torch, a channel locks, and a hammer, I was able to pull both pins. I didn't find any rust, but the bushing that I had to install on the pin was soft and bloated. I don't quite understand this as silicone grease is pretty innocuous.

I played around abit and I'm going to put it back together without the inner bushing, and just add more silicone grease to the pin to make up some the clearance difference.
I've tried it on the bench, and it seems to work like a charm. The pins slide easier than before, just like an XJ in fact.
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Old November 23rd, 2018, 05:47
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techno1154 techno1154 is offline
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Join Date: Apr 2003
Location: In the islands
Posts: 2,663
Re: Front Brake info

I wonder why?

My XJ have a set of those same calipers taken from the WK 1st generation. I to keep having problems with the right side not holding as good as the left. Twice I have had to remove the guide pins clean and lubricate them using break grease,...Oriley's offering after which they seem to work better,...until it throw another hissy fit (stubborn little SOB's to remove). One of the disc pads wear more than the other also.

Next go around, I will either change the bracket that holds the pads or try to find some better means of cleaning inside the guide tube. A different brand of rubber grease may be worth trying also.

1996 XJ; 4.0L; AW4; NP231; SYE; D30 and D44; ECTED; 4.10 gears; 30X9.5 -15 BFG/AT/KO; 3" lift; Rusty's LCA; JKS ADJ UCA; Kevins ADJ Track bar; Drawtite Front Receiver; Dual Electric Fans; Dual Battaries.
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Old November 23rd, 2018, 14:22
WB9YZU WB9YZU is offline
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Join Date: Feb 2004
Location: Madison, WI
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Re: Front Brake info

I got the parts from Oriley's also.

Except for the pins/bushings on the passenger side.
Oriley's was out of the pin kits, so I pulled the one free pin from each OEM bracket and re-used them.

I just took the passenger side apart and the pins move freely.

Still I pulled the bracket, put it in a vice, and slid the pins out to compare the bushings.
Eureka! The bushings are made of a different material.
The Oriley ones are soft and squishy, the OEM ones are hard.

To clean the bores, you could try a drill bit the size of the bore, or a brush from a gun cleaning kit.
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