What do you guys think?
I just replaced the F45 shocks and sway bars on my 99 coupe with 04 Z06 shocks and bars. Car has 120K on it and the F45 shocks were trashed, two of the shocks would not even rebound after being compressed. After the install I took the car on a nice hard drive in the coastal mountains. Car handled sooo much better. At first there was no noise by the time I got home (50 miles later) I noticed some clunking and groaning when pulling away from a stop, once car was above 5mph no noise. I have put about 500 miles on it since the switch and the noises have become progressively worse from the front and rear.
I’ve been back under the car 3 times now and am 100% positive the bars, end links and shocks are not loose. All the bushings look to be in pretty good shape and I cannot get any sideways movement on control arms. I’m just guessing at this right now as I have not done a real close inspection of the rubber leaf spring mounts but I think the mounts might have torn loose from my poor old springs due to the much stiffer sway bars exerting more torsion on the leaf spring assy there by letting the spring move around in the confines of the mount. I’m going to get in there in a few hours from now and see if that’s the case. Just wanted to check with you guys and see if someone else has seen this or if it makes any sense.

 

I had my rear swaybar off for a while, and when I put it back on I did not use any grease on the rubber bushings. This caused a creaking, groaning sound at low speeds. I loosened it up and put some grease used for stopping brake noise inside the bushing where it contacts the swaybar. Noise is gone. Maybe your noise is something this simple?

 

Used a bunch of lithium grease on the bushings. I was reading through some past post on this problem and found some info stating that with the end links disconnected the sway bar should move freely in the bushings, if not some washers may be needed to space the bracket or anopther possibility is the bushing might not be seated properly. It's hard for me to imagin the noises getting worse under those circumstances though. But it sounds more likly then the rubber mount becoming detached from the spring, either way I will find out tonight.
Thanks for the feed back.

 

I am gonna follow this thread because I have the same problem with my car. Suspension makes a clunking noise and it is hard to pin down where it is coming from. The noises started right after changing shocks and upgrading to Z06 sway bars with metal end links. Several inspections of the underside and no idea what is causing it.

 

I had a clunk in the rear of My 98 and could not find anything wrong under the car. Then one day I went to get My Manual out and noticed the jacking pucks and tire pressure gage and a few other tools I carry were loose in the bags in my compartment. I rubber banded everything and put them in a towel and all of My rattles and clunking sounds went away completly. Cheapest repair I have done yet on my car.

 

Same here. I started a thread in the "general info" forum about these very same sorts of noises and so far have not gotten a decent answer as to what could be causing that sound. And it pretty much started after having installed the Z06 swaybars and lowering on the stock bolts.

To me it sounds like the over-the-axle-part of the cat-backs were knocking against the underbody, but I can't find anything that's even close to the underbody to be making such a clunking, thumping sound.

I wonder if it could be the actual springs themselves, due to not having the same "load" on them as when before the shocks/swaybars and lowering was done?

 

mine creaks like crazy over any large bump...it's almost to the point of being embarassing. I wish there was a definite answer for this... my buddies 97 doesnt creak a bit but my 99 creaks like crazy. I do have coilovers and more miles than him tho

 

Last night I got the car back up on ramps in front and cinder blocks in the rear so car was level. Removed front and rear end links first and found that the sway bars were completely frozen in their bushings, meaning I could not rotate them at all. They were just installed last week so it’s not like the grease dried out. Removed the sway bar bushing brackets and re-greased the bushings with lithium-based grease. I then used aprox. 0.060” thick washers to space the brackets. After putting it back together the sway bars where still really tight in the bushings but at least a little better. Took her out for a spin afterwards, going through the neighborhood out to Hwy #1 no creaks, pops or groans, Oh Yea. Drove the S#*T out of it on some fairly winding roads, car handles great. Come back through the neighborhood over them F-ing speed bumps and it’s creaking and groaning again but no pops. Get in it this morning to drive to work, no noise at all over speed bumps and pulling away from stops. Get to work and pull of freeway it’s creaking and groaning.

Conclusion:
I really don’t think it’s a spring problem now.
Sway bars are binding up in their bushings, especially after car warms up (thermal expansion).


What to do about it:
Use thicker spacers???
Use a different grease…Teflon or silicone based???
Try after market poly bushings???

Sorry the post is so long I just thought I should share my thoughts.
I need to get this fixed it’s driving me crazy.
Dave

 

Ok, I just wanted to post finial results on this problem.
Thanks to forum member Joe G for his right on recommendation. The fix for the creaking /groaning suspension was the sway bar Poly bushing from Ecklers. I bought both front and rear bushing sets and installed the rear bushings about 4 weeks ago but did not do the fronts as I ran out of time. After installing the fronts it seemed a little better but was still real noisy so I thought, naw, this is not the problem. Then last week I was finialy able to do the front in between all the frickin rain were geting in CA. and sure enough all is good, no noise what's so ever.
I was really amazed at how much noise was transmitted through the frame, befor doing the fronts it sounded like half of the creaking and groaning was still coming from the rear.
Joe G you Da Man.

 

I have a clunk when i back up, as far as you say is, get new bushing?

Thanks for the info.

 

???? Need some more info
Did you change out your sway bars for Z06 bars and after get the clunking sound? If so, are you sure the endlinks are tight (53 foot lb)
Mine was groaning, sqeeking and cluncking during stop and go and going over speed bumps after the Z06 sway bar install and changing the front bushings to Ecklers Poly bushings cured all the noise problems.

 

After changing my sway bars my car made the same noise. Turned out the sway bar end links were not tightened down enough.

 

Got the same exact thing going on. Installed Z06 sways, and ever since, have had a clunk come from underneath the car. It is more prominent when going over a pot hole or railroad tracks and such.

It drove me crazy at first, for I thought the rear end was going to drop off or something. Took it to the dealership and after a full day with my car, they couldn't find it either. I always thought it was related to when the dealership swapped out the tranny and converter. Still bugs me.

 

For less then $50 for front and rear Poly bushings from Ecklers and aprox. 1 hour install time I think it's worth a shot.

 

Where exactly are these bushings located? I have the service manuals, and have not been able to locate the exact area where these are. Will removing the wheels, and lifting the car allow room to replace the bushings?

 

The sway bar bushings are sold as 23mm, and 25mm in size. I have a 2002 coupe. Will both sizes work? Is this a DIY job?

 

Ckeck this link it will tell you every thing you need to know.
http://www.ls1howto.com/index.php?article=16

 

Sorry for the late reply, I have a 2001 Z06. I grease the bushing and put the Z06 Aluminum endlinks. Still hear the noise.

 

I thought all Z06's came with the aluminum endlinks?? So what your saying is you changed plastic endlinks out for aluminum ones?
Again I would make sure that the endlinks are torqued correctly at 53ft/lbs. The endlink bolt thread is like a pipe thread, it is tappered, so the nut gets very tight before the endlink is really tightened down to the bar/control arm.

 

2002 and up has aluminum endlinks