[zeevert]

My 2009 CTS4 has had this hark clunk noise in the rear since I bought it a few years ago. I was pretty sure I knew what the problem was based on several threads on this forum. It was tough to confirm, especially when the suspension was loaded on the ground, or hanging by the shock when jacked up.

Most of the CTS's with this problem have been fixed under warranty, but for those of us out of warranty...

I finally made an effort to confirm that I had bad shock bushings a couple weeks ago. With the car raised, I put a jack stand under the knuckle to hold the suspension up, while I removed the lower shock bolt. With the shock detached, the bushing slipped right out of its outer steel sleeve. The steel sleeve was still pressed into the knuckle. (The rubber bushing is supposed to stay bonded to the steel sleeve.) Clearly this was not right. Both sides were the same.

There are replacement bushings on Ebay for $10-20/pc, but you'll need to press the old sleeve out, and press the new bushing in. Generally, this type of bushing is not supposed to be serviceable when pressed into aluminum.

In my searches for information, I never saw any pictures, so here are a couple:



They are out of position by about 1/4".

So, It looks like I needed a couple knuckle assemblies for $100-200 on Ebay.
But in the meanwhile, what the heck, I cleaned the parts with starting fluid and I slathered them with some grey Permatex and slid them back in, and bolted the shock back on. I jammed a plastic clip in-between the shock and knuckle to keep it centered. I let it cure for a day.

Amazingly, my clunk is gone. I don't know how long it will last....

 

[ksa8907]

I couldn't figure out how to get the old bushing out at first so I wrapped it in a couple layers of duct tape to reduce the clearance knowing I would have to fix it later. Amazingly its still quiet as can be 6 months and 12k miles later.

 

[zeevert]

Yeah, I figure there's not a lot of side-load on the bushing/shock. It doesn't take much to keep the bushing from sliding around.

 

[Joe]

I had the bushings replaced by a mechanic. The bushings are available after market and are cheap. The aluminum sleeve around the rubber is paper thin and the install must be done carefully and slowly. The mechanic crushed one and we had to order another. Since we changed them that clunk is gone but i also can hear one of my calipers banging; those are next.

best of luck

 

[ehughlett]

Well, here's a shot of my 09 CTS4 right rear shock bushing. With my index finger, I can pull down the lip of the bushing material that seems to have shifted out. I don't see this on the left side. Clunks over bumps. I'm going to buy a bushing extraction kit and replace it. Replacement bushings only about $40.

 

[Long]

Welcome, ehughlett.

Let us know how the replacement goes and be sure to include parts sources to help others out.
Best of luck with the repair!

 

[silversport]

yes and if you could share a bit more information about your car and where on the planet you drive (do you get Winter and salted roads?)...miles on your vehicle???...

hope this fixes up your ride...

Bill

 

[redheadedrod]

When I changed similar bushings in my truck I used a 2 step program to get them out. In my case the bushings were still connected to the sleeve. Funny how fast and how complete they burn when you light them with a butane torch. However the smoke coming off them should not be breathed... You may find another way to get them out but for me this was the simplest.

Once they are removed, shrunken or whatever method you use to get them out.... I used a chisel and hammer and collapsed the metal sleeve to the middle of the previous bushing and they come right out. Just be careful not to mar the metal in the arm. Not that it maters much if you do a little but you don't want to have any rough surfaces.

Cleaned up where the bushings went in, installed new bushings with a small press and away you go. Theoretically you could just use a long bolt, a nut and a couple of washers big enough to cover the whole bushing to use as an installation tool. A washer on each side of the arm, bolt through and tighten the bolt. The bushing will slide right in.

 

[Joseph Upson]

Looks like a safe location for a polyurethane bushing replacement. That service location shouldn't increase the harshness of the ride the way they tend to do when installed in the control arms. I believe that's why the performance strength poly engine mounts targeting the V sort of faded from the front lines as an upgrade. We typically want to know the motor is running without feeling that it is.

 

[Lifespeed]

If your car has significant miles on it and you just change the one bushing, you'll be back in there for more repairs sooner than you think. These cars have a design-flawed ABS tone ring in the hub, and the rest of the bushings in the upright will be worn as well.

If I were you I would change both knuckles and hubs, not just the bushing. Actually, I would replace all the rear suspension wear items if you're over 100K miles, but that is me - I'm a perfectionist when it comes to suspension. But just the lower knuckle bushing? Waste of time.

 

[Lifespeed]

And just to put it all in context, a new OEM knuckle is $129 plus shipping. So don't fart around with buying a bushing extractor kit and parts and pulling and re-using the old hub near the end of it's life. Don't pay your labor fiddling around, or the mechanic hourly rate. Mail order yourself a good deal on affordably-maintainable American car parts, save a bunch of time or labor $$ on the job, and have new stuff out back that will last. We all like a new rear end.

That's part of what is great about Cadillac, maintenance has the potential to be a lot more affordable than some other makes.

 

[wizzer]

well, this explains the clunk for the rear of the car when i hit a good size bump at speed! Thanks for the thread and info

 

[dandunham]

So what's actually clunking. Is it the shock against the knuckle?

 

[NorthernSRX]

I've got the same condition. Just finished overhauling my fronts. Replaced my rear shocks a few years back and now I have the clunk and a squishy sound. Have isolated it to the rear passenger side. No doubt it's this bushing.