4th Gen Trans Am Camaro and Firebird rear passenger side suspension clunk
06-14-2017, 11:39 AM
#21
cant believe I haven't seen this thread, I've been chasing down the same clunking noise described by the OP for a while now. I think I have it narrowed down to the upper shock mount area as well, I have Viking coil overs on my car with the upper mounting bracket and am thinking the part that goes around the upper spring seat may be moving causing it. all of my rear suspension is roto-jointed and tight so I have ruled all of that out. only other think I haven't checked is the swaybar endlinks so that is next.
06-14-2017, 02:17 PM
#22
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cant believe I haven't seen this thread, I've been chasing down the same clunking noise described by the OP for a while now. I think I have it narrowed down to the upper shock mount area as well, I have Viking coil overs on my car with the upper mounting bracket and am thinking the part that goes around the upper spring seat may be moving causing it. all of my rear suspension is roto-jointed and tight so I have ruled all of that out. only other think I haven't checked is the swaybar endlinks so that is next.
I think we are onto something here.... any set upbg with out those stock DeCarbons with the bigger rubber top mounts and we are getting a thump/clunk from the top shock mounts.
I just rechecked mine having stripped the interior for sound deadening and bouncing that car around makes the same noise we can hear when driving over nuisance bumps!
Its driving me nuts
Thinking about Bilsteins now instead of Vikings.. I aint putting the DeCarbons back on that's for sure !!!
06-15-2017, 03:00 PM
#24
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Be interesting to see how that works out and if the clunk goes away.. I am still thinking its coming from the top shock mounts. Will see what it sounds like when I finish my sound deadening project.. 
06-15-2017, 08:03 PM
#25
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Who all has taken a torque wrench to their LCA bolts?
Im remembering mine took around 100ft.lbs to tighten to not make noise, quite a bit more than what I could do with a regular wrench at that angle laying under the car.
06-16-2017, 09:08 AM
#27
My 98 never clunked back there.
My 99 clunked BAD.
Replaced a bunch of stuff (shocks, springs, LCAs, panhard, sway links), it is better but still clunks sometimes. I have been blaming the hokey exhaust that is hanging a little weirdly.
Of course, no clean marks to indicate anything hitting something else. Just noise.
Oh well, the car recently developed a very annoying squeak/rattle from the hatch and interior stuff so I can't hear the clunk that well anymore
Probably just need to take it all apart to tighten everything down again. Eventually...
My 99 clunked BAD.
Replaced a bunch of stuff (shocks, springs, LCAs, panhard, sway links), it is better but still clunks sometimes. I have been blaming the hokey exhaust that is hanging a little weirdly.
Of course, no clean marks to indicate anything hitting something else. Just noise.
Oh well, the car recently developed a very annoying squeak/rattle from the hatch and interior stuff so I can't hear the clunk that well anymore
Probably just need to take it all apart to tighten everything down again. Eventually...
06-16-2017, 12:09 PM
#28
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Well I'm gonna still bang on about the upper shock mounts 
I can hear the same clunk when I bounce the car from inside and the shock mounts are done up tight.
My LCA's have been torqued tight .. I had the car up real high so I could hang on the torque wrench.
Thing is why did the factory put the De Carbons on Fbodys with huge rubber top mounts.. I mean they are nearly twice the size of the after market stuff that comes in the little packet with you new Konis/ Bilstein/ Viking...
ive seen it and compared.. Its almost like the factory did a bit of extra work round that area to cut down on something.
Also there is that lump of yellow foam that covers the access hole to the top mount fasteners... I even tried to use the OEM rubber hardware and it wont work with after market shocks ... DOH !!!
I can hear the same clunk when I bounce the car from inside and the shock mounts are done up tight.
My LCA's have been torqued tight .. I had the car up real high so I could hang on the torque wrench.
Thing is why did the factory put the De Carbons on Fbodys with huge rubber top mounts.. I mean they are nearly twice the size of the after market stuff that comes in the little packet with you new Konis/ Bilstein/ Viking...
ive seen it and compared.. Its almost like the factory did a bit of extra work round that area to cut down on something.
Also there is that lump of yellow foam that covers the access hole to the top mount fasteners... I even tried to use the OEM rubber hardware and it wont work with after market shocks ... DOH !!!
06-16-2017, 12:16 PM
#29
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Well I'm gonna still bang on about the upper shock mounts
I can hear the same clunk when I bounce the car from inside and the shock mounts are done up tight. Its coming from the top shock mount area !
My LCA's have been torqued tight .. I had the car up real high so I could hang on the torque wrench.
Thing is why did the factory put the De Carbons on Fbodys with huge rubber top mounts.. I mean they are nearly twice the size of the after market stuff that comes in the little packet with you new Konis/ Bilstein/ Viking...
ive seen it and compared.. Its almost like the factory did a bit of extra work round that area to cut down on something.
Also there is that lump of yellow foam that covers the access hole to the top mount fasteners... I even tried to use the OEM rubber hardware and it wont work with after market shocks ... DOH !!!
I can hear the same clunk when I bounce the car from inside and the shock mounts are done up tight. Its coming from the top shock mount area !
My LCA's have been torqued tight .. I had the car up real high so I could hang on the torque wrench.
Thing is why did the factory put the De Carbons on Fbodys with huge rubber top mounts.. I mean they are nearly twice the size of the after market stuff that comes in the little packet with you new Konis/ Bilstein/ Viking...
ive seen it and compared.. Its almost like the factory did a bit of extra work round that area to cut down on something.
Also there is that lump of yellow foam that covers the access hole to the top mount fasteners... I even tried to use the OEM rubber hardware and it wont work with after market shocks ... DOH !!!
06-23-2017, 02:18 PM
#30
I have had a clunk/thud on the passenger side rear since owning the car. Its getting louder but nobody including myself has been able to pinpoint what it is. New shocks, springs, isolators checked, panhard bar bushings, lower control arms checked and torqued to 100 ft/lb, bearings in the axle checked etc. No spare tyre or jack, no loose panels. new bump stops, but no contact with them anyway... upper shock mounts I just checked last night after reading this post. The shocks are stock replacement so have the larger upper rubber mounts. Im at a loss but its damn annoying. only does it over 20 miles an hour and over larger pot holes/bumps.
06-26-2017, 11:45 AM
#31
Thing is why did the factory put the De Carbons on Fbodys with huge rubber top mounts.. I mean they are nearly twice the size of the after market stuff that comes in the little packet with you new Konis/ Bilstein/ Viking...
ive seen it and compared.. Its almost like the factory did a bit of extra work round that area to cut down on something.
Also there is that lump of yellow foam that covers the access hole to the top mount fasteners... I even tried to use the OEM rubber hardware and it wont work with after market shocks ... DOH !!!
My solution: bigger rubber mounts, and heater hose:
06-29-2017, 09:55 AM
#32
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The factory rubber mounts have a rubber tube on one side that's supposed to go through the metal and the other mount, so to prevent the rod from hitting the metal body. But this tube can become squashed, maybe from the factory. And the mounts that come with after market shocks do not have this, they just provide the usual small rubber donuts for each side of the body metal.
My solution: bigger rubber mounts, and heater hose:
My solution: bigger rubber mounts, and heater hose:
I completed my sound deadening job.. took me a week to strip/sound deaden and refit.. All really quite inside the car and even the clunk is noticeably quieter ! But its knowing what is causing it that is winding me up
Thoroughly recommend a layer of Rattle trap type deadener and a layer of MLV foam.. I can hear my analogue pillar mounted clock ticking now when I am at a stop light !!
07-03-2017, 08:40 PM
#33
The factory rubber mounts have a rubber tube on one side that's supposed to go through the metal and the other mount, so to prevent the rod from hitting the metal body. But this tube can become squashed, maybe from the factory. And the mounts that come with after market shocks do not have this, they just provide the usual small rubber donuts for each side of the body metal. My solution: bigger rubber mounts, and heater hose:
07-22-2017, 08:48 AM
#36
The hard thunk is typically bottoming out. Hitting the bump stop on the rear end. Inspecting my rear end I can see where the pan hard bar pivots and causes the drivers side to compress the suspension on the drivers side first, over rotate, and put the majority of the compression back on the passengers side and over compress the passengers side on the bottom end of the compression of the suspension
My theory atleast
With my new wheels having a more aggressive offset than my 17x11 zr1s, I can see a visible difference in rear alignment under compression. Now my car looks centered under the rear in the parking lot, but I can feel under the rolled edge of my fender on the passengers side and feel slimy rubber build up from the tire moving outwards under compression on the passengers side, again caused by the design and angle of the pan hard bar. Just changing to my more aggressive rear offset got rid of my thunk, because now my tire rubs the fender under hard compression
That's my theory, the rear end should be offset slightly to the drivers side at rest, so under compression of the suspension the rear end compresses level to the chassis
Also
If you are getting a rattle over bumps and pot holes it's a wheel bearing
My theory atleast
With my new wheels having a more aggressive offset than my 17x11 zr1s, I can see a visible difference in rear alignment under compression. Now my car looks centered under the rear in the parking lot, but I can feel under the rolled edge of my fender on the passengers side and feel slimy rubber build up from the tire moving outwards under compression on the passengers side, again caused by the design and angle of the pan hard bar. Just changing to my more aggressive rear offset got rid of my thunk, because now my tire rubs the fender under hard compression
That's my theory, the rear end should be offset slightly to the drivers side at rest, so under compression of the suspension the rear end compresses level to the chassis
Also
If you are getting a rattle over bumps and pot holes it's a wheel bearing
07-22-2017, 09:04 AM
#37
The hard thunk is typically bottoming out. Hitting the bump stop on the rear end. Inspecting my rear end I can see where the pan hard bar pivots and causes the drivers side to compress the suspension on the drivers side first, over rotate, and put the majority of the compression back on the passengers side and over compress the passengers side on the bottom end of the compression of the suspension
My theory atleast
With my new wheels having a more aggressive offset than my 17x11 zr1s, I can see a visible difference in rear alignment under compression. Now my car looks centered under the rear in the parking lot, but I can feel under the rolled edge of my fender on the passengers side and feel slimy rubber build up from the tire moving outwards under compression on the passengers side, again caused by the design and angle of the pan hard bar. Just changing to my more aggressive rear offset got rid of my thunk, because now my tire rubs the fender under hard compression
That's my theory, the rear end should be offset slightly to the drivers side at rest, so under compression of the suspension the rear end compresses level to the chassis
Also
If you are getting a rattle over bumps and pot holes it's a wheel bearing
My theory atleast
With my new wheels having a more aggressive offset than my 17x11 zr1s, I can see a visible difference in rear alignment under compression. Now my car looks centered under the rear in the parking lot, but I can feel under the rolled edge of my fender on the passengers side and feel slimy rubber build up from the tire moving outwards under compression on the passengers side, again caused by the design and angle of the pan hard bar. Just changing to my more aggressive rear offset got rid of my thunk, because now my tire rubs the fender under hard compression
That's my theory, the rear end should be offset slightly to the drivers side at rest, so under compression of the suspension the rear end compresses level to the chassis
Also
If you are getting a rattle over bumps and pot holes it's a wheel bearing
Not in all cases and certainly not with mine!
07-22-2017, 11:33 AM
#38
Yeah I'm probably over thinking it, but I've measured and my rear is centered to the quarter panels, but if I compress the rear the passengers side will bottom out lower than the drivers rear,
or more likely my pan hard bar could be bent and be causing that distortion. But my slight tire rub under full compression solved my thunk in the passengers rear
Just my 2 cents, don't take it as gospel. I might remove my rear sway bar to see if that helps compensate for the pan hard bar adjusting the position of the rear end under compression of the suspension
or more likely my pan hard bar could be bent and be causing that distortion. But my slight tire rub under full compression solved my thunk in the passengers rear
Just my 2 cents, don't take it as gospel. I might remove my rear sway bar to see if that helps compensate for the pan hard bar adjusting the position of the rear end under compression of the suspension