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Discussion Starter #1
The Commander is getting really clunky over sharp bumps, like manhole covers and potholes. Progressive compression/droop is smooth and noise-free. It seems to be coming from both sides. My experience with bad ball joints seems to be more of a popping sound, and worsened by turning one direction or another, and that doesn't seem to be the case here.

103xxx miles at this point, and I've replaced the shocks and shock mounts, sway bar bushings and end links, none of which had any effect on the clunking.

Where should I be looking next?
 

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Discussion Starter #3
I haven't been able to see anything visibly over worn or degrading.
I'm also noticing the clunks are much easier to replicate when only one tire hits the bump (either front) whereas a sharp speed bump where both tires hit at the same time takes a bigger jolt to clunk. This to me points to the sway bar, as it should be the only motion that is changed by one wheel bouncing vs two. so having replaced all the sway bar attachment points has me baffled.
 

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Discussion Starter #4
I noticed I missed your question there. No, hard acceleration/deceleration does not trigger the clunks. Neither do large, rolling, albeit aggressive speed bumps where the whole vehicle rocks like a boat. In fact, in those cases I sometimes hear a clunk from the rear axle.
 

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Hrm. Well there are two different sway bar diameters available. Maybe you have the smaller sway bar and the bigger bushings?
 

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Discussion Starter #6
I have the overland, which should be the bigger bar. And I did double check with a caliper before installing the bushings, so I know they are correct for the application. I'll dig around under the Commander more today and see if I come up with any new information. Thanks for the input so far!
 

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Also replace the swaybar end links that really made a difference on mine as well.
 

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Discussion Starter #10
Even though my clunk didn't seem to be described by that thread, I went ahead and bought a set of external torx sockets and tightened the steering rack. No change. I also saw a thread about tightening the sub frame bolts so I'll try that next. Everything I see under there looks to be in good shape, with no more that minor surface cracking on a couple lower control arm bushings.
 

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Even though my clunk didn't seem to be described by that thread, I went ahead and bought a set of external torx sockets and tightened the steering rack. No change. I also saw a thread about tightening the sub frame bolts so I'll try that next. Everything I see under there looks to be in good shape, with no more that minor surface cracking on a couple lower control arm bushings.
Hrm. Sounds like you've hit all the places I would consider based on your information.

The top nut on my shocks weren't torqued down all the way after install and I had to go back and crank those down after the fact. That was more noticeable on one side than the other though.
 

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Discussion Starter #12
I went in and tightened the heck out of the subframe connecting bolts as found in another thread and tightened the steering torx bolt again, as well as went in and tightened down the shock top nut, and there is absolutely no change in the clunk.

As I was coasting slowly down my driveway, I decided to quickly turn the steering wheel back and fourth repeatedly and I was able to reproduce what sounded like a very quite version of the clunk. But I don't think that gets me anywhere. I further inspected the bushings around the front end and nothing looks too beat up, including the front diff bushings.
 

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check the front differential bushings if you haven't already
 

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Discussion Starter #14
Well I took it in to a shop, and they told me it was sway bar bushings. Even after telling them I'd just replaced the bushings, they stuck to their guns and insisted that the sway bar bushings were the source of the clunk, and they even reproduced it with manual movement. They were willing to change them out for me for the low-low price of $256!

I triple checked my sway bar diameter, and I'm at 1.34", as I'm now believing all 07+ Commanders are. This means I got the correct size MOOG bushing the first go around, but I'll change them out again and see where I'm at. Going with Raybestos this time. Will update, but I'm admittedly not overly hopeful.

Also, does anyone know what those metal tabs/retainers on the outboard sides of the bushings are/what they do? I've never seen such a thing on a sway bar, and I'm not sure what they're supposed to do. One of mine was an inch or more from the bushing, so I hammered it in to touch the bushing as it's the only purpose I could imagine it serving is to prevent axial movement.
 

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Well I took it in to a shop, and they told me it was sway bar bushings. Even after telling them I'd just replaced the bushings, they stuck to their guns and insisted that the sway bar bushings were the source of the clunk, and they even reproduced it with manual movement. They were willing to change them out for me for the low-low price of $256!

I triple checked my sway bar diameter, and I'm at 1.34", as I'm now believing all 07+ Commanders are. This means I got the correct size MOOG bushing the first go around, but I'll change them out again and see where I'm at. Going with Raybestos this time. Will update, but I'm admittedly not overly hopeful.

Also, does anyone know what those metal tabs/retainers on the outboard sides of the bushings are/what they do? I've never seen such a thing on a sway bar, and I'm not sure what they're supposed to do. One of mine was an inch or more from the bushing, so I hammered it in to touch the bushing as it's the only purpose I could imagine it serving is to prevent axial movement.
$256!!!!!! :mofo:

Mine cost me $15 and 15 mins maybe.
 

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Discussion Starter #16
Given that they would have it on a lift and have impact drivers, it's a 5 minute job at best, so even with the inflated price of their bushings themselves, they're still paying themselves over $2,500/hr! Clearly I'm in the wrong line of business!!
 

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Discussion Starter #17
Well heck, I've got to throw my arms up on this one!

I changed out the bushings today with the Raybestos and took it on a pretty thorough test drive over rough potholed roads, over metal plates, speed bumps, and even drove diagonally off a curb, and the clunk is GONE!

The old (new) bushings were full of sand from my trip to the dunes, but were otherwise physically perfect as far as I could tell. The brackets showed no signs of movement, and the bolts required a breaker bar to get out. The Raybestos bushings looked identical to the MOOGs, including the color (blue). I was hoping they would be regular old rubber, but they're thermoplastic (harder), just like the MOOGs.

The only thing I can think of is that I didn't use a torque wrench to tighten down the MOOGs to the specified 95 lb-ft. Though by my guess removing them, I was right in that 95 lb ft range. And like I said, I saw no signs that they had been moving. This time I used the torque wrench, and finished the job CERTAIN there would be no change in the clunk. But hey, it sure felt good to be wrong!
 

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Not to be dumb...even though I am right now, just got back from overseas...and when I accelerate I get that jolt and pop...so what is it?...just the joints?
 

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Schlotzky did you replace them with the 1.34" ones or the 1.29"? When I replaced mine I had to use a breaker bar to unscrew the bolts and then again to rescrew them I thought I was going to break them it was just very hard to put them back in.
 

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Schlotzky did you replace them with the 1.34" ones or the 1.29"? When I replaced mine I had to use a breaker bar to unscrew the bolts and then again to rescrew them I thought I was going to break them it was just very hard to put them back in.
WHen i replaced mine I used the 1.34" ones. Not sure that I have heard of any XK's using the smaller ones. Maybe some of the earlier models?
 
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