High Speed Shimmy and Bushings
03-21-12, 12:47 PM
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High Speed Shimmy and Bushings
After thinking for years my high speed shimmy was due solely to bad tires, I've finally figured out that a good portion of the shimmy I feel at 77mph-85mph was due to old bushings.
After replacing the front strut rod bushings (with OEM) my shimmy was improved, but not by much (although the braking was MUCH better...I thought it was bad rotors - and it also got rid of the infamous 'clunk' during hard braking at low speed).
Next I replaced the sway bar bushings (with OEM). Although I replaced them just based on general advice from these forums, and thinking it would just help the steering/cornering response, much to my surprise the high speed shimmy is almost gone! I was shocked and pleasantly surprised. What is also surprising about the improvement is that the old bushings really didn't look that bad. The bar was very slightly loose and the rubber slightly hard compared to the new ones, but I wouldn't have thought they were that bad.
There is still some shimmy at high speed, but I guess that's due to old/crappy tires and original shocks (1998 @ 217,000 miles). Can't wait to get new shocks.
I think I need rear carrier arm bushings as well. That could also be an issue with the shimmy.
On a side note, the creaking I hear from my sunroof area ALL THE TIME was not present at all during my 30 minute test drive today (so nice).
I've found that chasing vibrations/shimmies is a very involved process. My best guess is that all parts play together... IE if there is a slight issue with a tire (or bushing, or shock, etc), it resonates with other parts that need attention, making the whole drive worse (and making diagnosis very difficult).
After replacing the front strut rod bushings (with OEM) my shimmy was improved, but not by much (although the braking was MUCH better...I thought it was bad rotors - and it also got rid of the infamous 'clunk' during hard braking at low speed).
Next I replaced the sway bar bushings (with OEM). Although I replaced them just based on general advice from these forums, and thinking it would just help the steering/cornering response, much to my surprise the high speed shimmy is almost gone! I was shocked and pleasantly surprised. What is also surprising about the improvement is that the old bushings really didn't look that bad. The bar was very slightly loose and the rubber slightly hard compared to the new ones, but I wouldn't have thought they were that bad.
There is still some shimmy at high speed, but I guess that's due to old/crappy tires and original shocks (1998 @ 217,000 miles). Can't wait to get new shocks.
I think I need rear carrier arm bushings as well. That could also be an issue with the shimmy.
On a side note, the creaking I hear from my sunroof area ALL THE TIME was not present at all during my 30 minute test drive today (so nice).
I've found that chasing vibrations/shimmies is a very involved process. My best guess is that all parts play together... IE if there is a slight issue with a tire (or bushing, or shock, etc), it resonates with other parts that need attention, making the whole drive worse (and making diagnosis very difficult).
Last edited by Live4brew; 03-21-12 at 12:56 PM.
03-21-12, 01:50 PM
#2
I have a 96 LS400 with 139k on it. I have been slowly going through the bushings in search of the perfect ride.
I suspect the lower control arm bushings are shot. I have an occasional thud coming from the front mostly during backing. I have already done upper and lower ball joints and the strut rod bushings.
There is conflicting information here, but I think the Adus 530 will fit in my lower control arm.
Good luck with your remaining shimmy!
I suspect the lower control arm bushings are shot. I have an occasional thud coming from the front mostly during backing. I have already done upper and lower ball joints and the strut rod bushings.
There is conflicting information here, but I think the Adus 530 will fit in my lower control arm.
Good luck with your remaining shimmy!
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