Rear end clunking

[Vapour Trails]

In past few months I've developed a clunk from the rear suspension. It started out pretty mild and not all that consistent. I thought it could be the DS, which is pretty noisey most of the time.

I installed polyball J&M LCAs in July and didn't have any noise/clunking immediately after installation. Bolts were torqued to spec with blue loctite.

I checked the torque on the upper shock nuts a few weeks ago and they seemed fine.

Yesterday I firmed up the rear shocks (D-specs) and added a few psi to the rear tires. All of a sudden I got wicked loud clanking from the rear end over rough terrain. I've thought about the mufflers possibly striking the underside of the car, but they never did this before and the hangers/mounts should be tight. It definately sounds like metal-metal contact.

I'm going to get under the car today and check the tightness of all fasteners but I'm starting to wonder if I've torn the diff to UCA bushing completely. The UCA is currently stock. Anybody else destroy this bushing with a stock UCA?

The rear suspension is: Steeda sport springs, d-specs, J&M LCAs, the rest is stock.

 

[Sleeper_08]

The diff to UCA bushing is the only one in my rear suspension that is still stock.

I'm running less HP than you but so far it seems to be holding up even after 15 track days and 25 K KM.

 

[Kaldar142]

Check to see if your over axle pipes are hitting the axle

 

[Vapour Trails]

Check to see if your over axle pipes are hitting the axle

Will do, but the exhaust has been the same for over one year, I can't see why all of a sudden it's hitting things.

The diff to UCA bushing is the only one in my rear suspension that is still stock.

I'm running less HP than you but so far it seems to be holding up even after 15 track days and 25 K KM.

I'm wondering if launching the car hard since the SC suddenly ripped it, but soft shock setting were masking it a bit.

I wish I could just go home and deal with this as the last AutoX/Drag racing weekend is 5 days away. I can't go and feel confident with these damned noise!

 

[bigwilly43729]

I've concluded that this car just fucking clunks. I replaced the LCA's and UCA mount along with the associated bolts about 2 or 3 weeks ago. No clunks. Now there is a clunk every now and again. I put it in gear and the entire rear end sounds like it's trying to separate itself from the car.

It's disheartening, but I'll just let my radio drown it out once I get it re-installed.

 

[Kaldar142]

the clunking sound you are describing sounds exactly like when my pipes were banging the axles, happened out of no where too.

I would check the LCA/UCA bushings too, had that happen to me too. all my bushings were bad (wtf? lol)

 

[Vapour Trails]

the clunking sound you are describing sounds exactly like when my pipes were banging the axles, happened out of no where too.

If this is the case, what's the fix?

 

[Kaldar142]

i just re-arranged them basically, you could see when i would go over rough terrain / bumps that the axle would bang the pipes. i made it so the pipes sat farther back and i also turned my shocks to full stiff.

It hardly happens anymore but ever so often when i hit a really hard bump it will do it.

my solution? Stiffer suspension... ground control coilovers FTW

 

[DusterRT]

To help combat my own axle-exhaust collisions, I used some 2-part epoxy putty to fill in the bottom voids in the rear exhaust hangers..hypothesis being, when the car hits a bump, the rubber hangers let the pipes sag momentarily. Didn't fix it completely, but helped some. My issues came from the mid-muffler pipes not fitting well though..I had zero noise previously with the OEM pipes.

 

[maxpayne]

In past few months I've developed a clunk from the rear suspension. It started out pretty mild and not all that consistent. I thought it could be the DS, which is pretty noisey most of the time.

I installed polyball J&M LCAs in July and didn't have any noise/clunking immediately after installation. Bolts were torqued to spec with blue loctite.

I checked the torque on the upper shock nuts a few weeks ago and they seemed fine.

Yesterday I firmed up the rear shocks (D-specs) and added a few psi to the rear tires. All of a sudden I got wicked loud clanking from the rear end over rough terrain. I've thought about the mufflers possibly striking the underside of the car, but they never did this before and the hangers/mounts should be tight. It definately sounds like metal-metal contact.

I'm going to get under the car today and check the tightness of all fasteners but I'm starting to wonder if I've torn the diff to UCA bushing completely. The UCA is currently stock. Anybody else destroy this bushing with a stock UCA?

The rear suspension is: Steeda sport springs, d-specs, J&M LCAs, the rest is stock.

Only the UCA has the polly ball....the LCA's have just regular bushings...but here's something from j&m that might help you if your bushings are done
J&M now offers a limited lifetime warranty on the bushings should they ever need replacing!

 

[Vapour Trails]

Only the UCA has the polly ball....the LCA's have just regular bushings...but here's something from j&m that might help you if your bushings are done
J&M now offers a limited lifetime warranty on the bushings should they ever need replacing!

http://www.hotpart.com/shop/index.php?l=product_detail&p=45

Not true, the poly ball is used in certain LCAs. I assembled the bushings when I installed the LCAs, there's a ball alright.

I sincerly hope 2-3 months of use didn't destroy the bushings already.

 

[max2000jp]

I don't see sway bars in your sig, but that was the source of my clunck. The bolt holding the sway bar endlink had come loose and caused an annoying clunk.

 

[Pony DNA]

I've concluded that this car just fucking clunks. I replaced the LCA's and UCA mount along with the associated bolts about 2 or 3 weeks ago. No clunks. Now there is a clunk every now and again. I put it in gear and the entire rear end sounds like it's trying to separate itself from the car.

It's disheartening, but I'll just let my radio drown it out once I get it re-installed.

Hey willy,

My car's rear end is made up of: BMR LCA Relocation Brackets, Steeda Adjustable LCA's modified with custom bushings and steel sleeves on the chassis side and Aurora Teflon lined rod-ends on the axle side, Steeda adjustable comp/street UCA w/HD UCA mount, Tokico D-Spec dampers, Steeda adjustable coilover spring seats, Hypercoil 250lb. springs, Steeda 20.6mm anti-roll bar with billet links and a Saleen PJ Watt's Link. If this rear end doesn't make noise nothing should!

If you get desperate come over to my house, bring a case of cold Sam Adams Boston Lager in glass and I'll help you fix your rear end noises. What's in your S197's rear end?

HTH!

 

[Lee's05GT]

come to think of it....since ive installed my d-specs and steeda springs, Everytime I go over say railroad tracks I hear something from the rear too, sees like something is loose or something, Ive checked EVERYTHING to see if something was loose, but nothing. It drives me crazy to think that something is wrong. The d-specs are set 4 turnes from full hard in the rear. AND how do you like those J&M lca's? I have a set that I have yet to put on mine.

 

[Vapour Trails]

Well it was the muffler hitting the bracket that contains the rubber hanger/insulator thing. There is very little clearance between the muffler and bracket (using steeda mufflers aka Borla Stingers) maybe 1 cm. Rubber must have weakened and is now allowing more movement. I jammed some peices of rubber bushing into the voids and it's tighter now but still clanked a couple times on the way to work this morning. Roads here are likely no better than the ones in Iraq or Afghanistan.

I also realized that some of the clunking from the rear was the back panel of the trunk, which has never fit tightly like it should. I took some dynomat and felt pads and placed them in strategic spots to insulate the panel from the body of the car and it now fits much tighter. This mornings drive confirmed this panel was the source of some of the annoying noises.

 

[bigwilly43729]

Hey willy,

My car's rear end is made up of: BMR LCA relocation brackets, Steeda Adjustable LCA's modified with custom bushings and steel sleeves on the chassis side and Aurora Teflon lined rod-ends on the axle side, Steeda Adjustable Comp/Street UCA w/HD UCA mount, Steeda coilovers, Steeda 20.6mm anti-roll bar with billet links and a Saleen PJ Wtt's linksage. If this rear end doesn't make noise nothing should!

If you get desparate come over to my house, bring a case of cold Sam Adams Boston Lager in glass and I'll help you fix your rear end noises. What's in your S197's rear end?

HTH!

BMR adj. LCA (poly/rod ends)
CHE adj UCA (poly ends)
BMR UCA mount
CHE adj Panhard bar (poly ends)
CHE Panhard bar brace
CHE LCA relocation brackets (not welded in)
BMR swaybar
Steeda axle bushing
CHE Axle brace

Like I said, I just replaced the LCA's & nuts/bolts and the UCA & nuts/bolts just a few weeks ago. On the initial test drive, everything was fine. Now the clunking is back. Guess I'll have to get under there again and take a look.

This car is really starting to piss me off....

 

[Vapour Trails]

I'm a dumbass, the real culprit was the front strut nut on the drivers side got loose again (2nd time). It was finger tight. There must be grease on the threads because I've torqued it to spec two times only for it to come completely loose in short order. Blue loctite to the rescue.

Willy, your suspension should really not clunk at all. Are you doing the work or is a shop? I'd bet a lot of shops don't torque bolts to the proper spec with a torque wrench. They just hammer it on with a impact gun. I did my own suspension install and other than this recent incident my suspension has been quiet. I didn't have any prior experience, just followed the shop manual and used a torque wrench.

 

[Pony DNA]

I'm a dumbass, the real culprit was the front strut nut on the drivers side got loose again (2nd time). It was finger tight. There must be grease on the threads because I've torqued it to spec two times only for it to come completely loose in short order. Blue loctite to the rescue.

Willy, your suspension should really not clunk at all. Are you doing the work or is a shop? I'd bet a lot of shops don't torque bolts to the proper spec with a torque wrench. They just hammer it on with a impact gun. I did my own suspension install and other than this recent incident my suspension has been quiet. I didn't have any prior experience, just followed the shop manual and used a torque wrench.

Hi Vapror,

Actually grease on the threads is not the problem. A properly torqued fastener in good condition will not loosen even with oil on the threads. Read that sentence, the key phrases are "properly torqued" and "fasteners in good condition." If you have a high quality torque wrench which has been calibrated recently the only other possibility is worn fasteners.

HTH!

 

[bigwilly43729]

I'm a dumbass, the real culprit was the front strut nut on the drivers side got loose again (2nd time). It was finger tight. There must be grease on the threads because I've torqued it to spec two times only for it to come completely loose in short order. Blue loctite to the rescue.

Willy, your suspension should really not clunk at all. Are you doing the work or is a shop? I'd bet a lot of shops don't torque bolts to the proper spec with a torque wrench. They just hammer it on with a impact gun. I did my own suspension install and other than this recent incident my suspension has been quiet. I didn't have any prior experience, just followed the shop manual and used a torque wrench.

I've done it both ways. Torque wrench and impact gun. I couldn't get a torque wrench in there for the UCA bolt.

Everyone has their bugaboo on this car. Mine just happens to be the suspension. I'll figure it out eventually.

 

[SoundGuyDave]

When doing the suspension, crowsfoot bits are your best buddy...