# All bushings replaced. Now front end thumping!



## Sproboscis (Aug 4, 2011)

Last weekend my son and I replaced all of the front bushings on a 2004 GTO M6. Had a full alignment and wheel balancing done. I cannot believe how sloppy it drove before. Its fantastic right now. Only one problem. The front end has a "thumping" sound going over bumps. More pronounced on the right than the left. I have gone over everything and nothing is loose. The car drives great! It never had the thumping before the bushings upgrade. Anybody have any ideas?


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## jpalamar (Jul 22, 2008)

I'm assuming you went with Poly bushings. They are stiffer then the stockers so you will feel more vibrations... maybe considered thumping to some?


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## Sproboscis (Aug 4, 2011)

All poly urethane. Zero vibration at all. The odd thing is that the thumping over bumps only is more pronounced on the right side. The car tracks beautifully.


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## LS2 MN6 (Jul 14, 2010)

I assume you tightened everything to spec?

I had to retighten my radius rod nuts (on the control arms) and on the frame after 10 miles to spec as apparently I didn't have them torqued good enough.

Also double check the torque on your Control Arm to frame bolts.

After that my thumps went away. I think it was the radius rod bumping the sway bar.


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## Rukee (Feb 8, 2007)

T Stine said:


> On the thumping noise check make sure your brake calipers are strait not turned


How could you possibly install the caliper turned?? Seriously.


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## svede1212 (Nov 1, 2005)

I'd check the sway bar and end links.


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## Sproboscis (Aug 4, 2011)

svede1212 said:


> I'd check the sway bar and end links.


That was it! Passenger side sway bar link wasnt tightened as much as it should have been. Now just a very, very slight steering vibration between 65-80 mph. Very livable. Thanks for the input.


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## Rukee (Feb 8, 2007)

There shouldn't be any vibration, I would have the tires balanced.


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## HP11 (Apr 11, 2009)

Rukee said:


> There shouldn't be any vibration, I would have the tires balanced.


He did.


Sproboscis said:


> Had a full alignment and *wheel balancing done*.


But you might want to have the alingment checked again as tightening the link might have affected it.


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## Rukee (Feb 8, 2007)

Sway bar links will not effect the alignment. And someone may have not done the ballance right, or a weight might have fallen off.


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## HP11 (Apr 11, 2009)

Rukee said:


> Sway bar links will not effect the alignment. And someone may have not done the ballance right, or a weight might have fallen off.


True. Maybe I'm reaching here but if the balance was done on an on-the-car wheel balancer, could a loose sway bar link have an affect?


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## Rukee (Feb 8, 2007)

HP11 said:


> True. Maybe I'm reaching here but if the balance was done on an on-the-car wheel balancer, could a loose sway bar link have an affect?


No. sway bar only effect handling by keeping the car flat in the corners, doesn't effect tire balance or alignment.


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## svede1212 (Nov 1, 2005)

A slight vibration could be the wheels weren't torqued on correctly. Uneven or improper torque on the lug nuts can cause the wheel to "warp". Loosen them and retighten them in a "star pattern" first to 55# and then to 95#.


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## gtothis (Oct 5, 2011)

Sproboscis said:


> That was it! Passenger side sway bar link wasnt tightened as much as it should have been. Now just a very, very slight steering vibration between 65-80 mph. Very livable. Thanks for the input.


Try lifting the car on jack stands. loosen both sides of the sway bar link and re-tighten them. Rotate tires if they were rotated at the alignment shop. 

I sent you a PM.


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## amdoverclocker (Dec 21, 2010)

I had a similar problem. Mine ended up being the sway bar links where moving in the sway bar bolt hole. I added a rubber piece to center the bolt in the bigger then needed hole in the sway bar.


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