Front End Shimmy At 60 Mph Resolved

[slate67]

Hey all:

I posted a few weeks ago about the fact that I was undertaking a total suspension refurb and that I would post the process with pictures for all to refer to. I am sorry that I was not able to do that because of time but will offer some findings.

I replaced the front shocks and rear struts with KYB GR2s. I also got the suspension bushing kit from TM engineering as well as the steering rack bushing kit. I replaced the tie rod ends and the lower ball joints (from what I have seen they give out around 75,000 and I have 75,500 on my GS4.

I completed the refurb with standard tools (no compressor) and a cheater bar (30 inch steel pipe). Since I did this in my garage and still work full time it was completed a few hours at a time over the course of 4 weeks. I did have to get a loaner ball joint puller kit and the spring compressor kits from a parts store but got my money back when I returned the kits (approx $150). I borrowed a torque wrench because mine only went up to 76 pounds and you will need to torque up to 123#.

I took the #1 and #2, and upper control arms to a machine shop to have the bushings pressed out and the new nylon bushing pressed into control arm #2 ($40 each side =$80). I used rustoleum rust stop primer and top coat spray paint on the control arms after brushing the rust off (repainted since the control arms were glass beaded and chamfered as part of the bushing removal/ install process and I didn't want bare metal to corrode.

You will need a copy of the repair manual to get torque specs and assist in the removal/ installation process. I found mine invaluable (it is a papar 2 volume repair manual, not the CD version that I saw posted on line many years ago). I bought it on e-bay 4 years ago for under $200 but I cannot recall how much I paid. I remember thinking it was way too expensive when I could buy a Chilton's for $15, but this 2 volume set is huge and very detailed. The books combined must be 8-10 inches thick.

The skill level for this I would place at moderate. I have never done this before but consider myself a DIYer and have mechanical ability. When I spoke with TM engineering about the refurb I was planning they recommended that the steering bushings be replaced at the same time. I now know that this makes a lot of sense since the steering rack must be loosened to get out the adjustment cam bolt from the lower control arm. If you have to loosen it up anyway why not replace them.

Seeing the bushings after I removed the control arms I now know why the front end vibrated so wildly at 60-70 MPH... They were pieces of rubber crap.

I could twist the stuff with my bare hands and, in my opinion, the bushings were shot. Although I am no mechanic I believe the bushings are the sole reason for the shimmy that I have put up with for 4.5 years. I tried all the "fixes" noted on this site - tire balancing, tire load balancing, tire pressure adjustment, steering pre-tensioner stiffening and nothing worked.

Amazingly when I pulled my car out of the alignment shop yesterday and took the thing up through 75 MPH no shimmy, not even a tiny one. I had a smile on my face instead of the frustration I normally experienced in that range. Some other observations.

The KYB GR2s are stiffer than the OEM shock/struts. I used the existing coils and I believe the car rides a bit higher though I did not measure before and after install. This could also be due to the bushings not being rubber mush. With my chrome rims I could feel a lot of the road - it is now a stiffer less forgiving ride but it is a lot more fun on corners with much less body roll. Interestingly we had an ice storm last night so I put on my snow tires (Blizzak WS50s) and drove those to work today. The tires are a softer rubber with gripper fins that absorb some of the road feel and ease up the ride. I put these tires on OEM 16inch rims from a 2003 ES300. The ride is smoother with the snows on.

Bottom line is that a suspension refurb is definitely the fix for the front end shimmy that everyone notes between 60-70 mph. Had I known I would have done this years ago, like as in when I first noted the shimmy. I think the parts were just under $800 from TM engineering (great guys) and the bushing machine work $80, and $10 for paint (plus my time for $0) = approx $890 total. The solution to an annoying shimmy and enhanced steering and cornering performance..... FREAKIN' PRICELESS. :D

[BillyShaft]

Congrats man!

Sounds like you put a bunch of effort in this and did a great job! Thanks for posting up the experience too.

I have considered several times purchasing the REAL service manuals like you did and maybe I will actually pull the trigger this time...it sounds like they really are invaluable for any heavy maintenance.

~Brian

[dcfish]

Great writeup Thanks for sharing B)

[sakataj]

this actually isnt ALWAYS a fix....has been discussed before and isnt always the solution but i haven't done the bushing kityet! i did do front lower ball joints, new tires, road force balance, new oem lug nutts, new weights, new shocks, aftermarket springs, tried the steering tensioner adjustment (although never finished this one) DIDNT do tie rods but will be doing so soon and mine is very unnoticeable nemore! would like it completely gone though so i might try this, i saw u said u got the bushings from tm engineering? got a link and how much were they? nice write up btw

see old discussions....different site. im on there also AND if u read them in included in the discussions as we all tried to fix this....15 pages of discussions on this one alone

http://www.clublexus.com/forums/gs-second-...ines-fixed.html

http://www.clublexus.com/forums/gs-second-...adjustment.html

[slate67]

this actually isnt ALWAYS a fix....has been discussed before and isnt always the solution but i haven't done the bushing kityet! i did do front lower ball joints, new tires, road force balance, new oem lug nutts, new weights, new shocks, aftermarket springs, tried the steering tensioner adjustment (although never finished this one) DIDNT do tie rods but will be doing so soon and mine is very unnoticeable nemore! would like it completely gone though so i might try this, i saw u said u got the bushings from tm engineering? got a link and how much were they? nice write up btw

see old discussions....different site. im on there also AND if u read them in included in the discussions as we all tried to fix this....15 pages of discussions on this one alone

http://www.clublexus.com/forums/gs-second-...ines-fixed.html

http://www.clublexus.com/forums/gs-second-...adjustment.html

http://www.tmengineering.net/suspension/daizen/make/gs.html

If I had not done the work myself I would not have been able to discuss the bushings. I will hypothesize for you the following: Since the parts you noted are all atached to the control arms in some way, and since the only interface between the control arms and the body of the vehicle are the bushings, it will make little difference in the shimmying if the bushings are, and I use the term in the textbook definition of the word - crap. In order to see the bushings you have to remove the shock, the upper ball joint, the wheel hub assembly, the number 2 control arm (which BTW the OEM bushing was not as bad as the #1 OEM bushing)and then loosen up the steering rack to press out the cam adjustment bolt, thereby being able to remove the #1 control arm and seeing the bushing. It is a lot of work for a look see and it is the only way to see what I mean. Had I been able to take pictures you would be able to see what I did.

Good luck.

[sakataj]

http://www.tmengineering.net/suspension/daizen/make/gs.html

If I had not done the work myself I would not have been able to discuss the bushings. I will hypothesize for you the following: Since the parts you noted are all atached to the control arms in some way, and since the only interface between the control arms and the body of the vehicle are the bushings, it will make little difference in the shimmying if the bushings are, and I use the term in the textbook definition of the word - crap. In order to see the bushings you have to remove the shock, the upper ball joint, the wheel hub assembly, the number 2 control arm (which BTW the OEM bushing was not as bad as the #1 OEM bushing)and then loosen up the steering rack to press out the cam adjustment bolt, thereby being able to remove the #1 control arm and seeing the bushing. It is a lot of work for a look see and it is the only way to see what I mean. Had I been able to take pictures you would be able to see what I did.

Good luck.

all i was saying was, this wasnt a miracle cure....other things could be causing this but if you think about it, it does make sense. i guess i'll try this! thanks again.....

have a merry christmas every1