Bon

I thought I'd post an update about my front end shakes that I've been working on eliminating since I bought my SC. They used to occur anywhere between 55-70 mph. The remaining shake occurs around 65-70 mph. I should mention that when I added H&R 25mm wheel spacers in the back and 20mm spacers in the front. I had the shakes both before and after adding the spacers though. The following list is what I've done over the past couple of years to try to eliminate my shakes:

1) New tires - Bridgestone Potenza's, nice tires, better ride.

2) Replacement, chrome, OEM wheels. Look nice. Didn't help or hurt.

3) Road force balancing. Helped a bit.

4) Steering rack was replaced with a rebuilt unit because the old one was leaking. Didn't help or hurt. Came with inner tie rods and I put on new outer tie rods at the same time. No change in shaking.

5) Daizen polyurethane lower control arm #2 bushings. Didn't seem to help.

6) Daizen upper control arm and lower control arm bushings. Didn't seem to help.

7) Daizen steering rack polyurethane bushings. Ah Ha! This helped a lot. Still not perfect, but this made a huge difference.

I did the steering rack bushings today. I've really, really developed a dislike for Lexus steering bushings!

Some background: I had issues with my '01 LS430 steering bushings @ 85K miles. My only choice was to replace them with OEM. I should have replaced them at 50K. They were really, really awful. The interesting thing, though, is that they physically looked pretty good. The result is amazing; nice and tight.

The bushing design of the SC is essentially the same as the LS. But luckily we have more choices with our steering rack bushings than the LS crowd. I began to hang around the GS guys because their front end is quite similar. The '98-'05 GS430 uses the same steering rack and bushings as our SC. Sewell sells both OEM and an aftermarket polyurethane solution for around $30 complete.

At this point my SC tracks very, very well. The polyurethane suspension bushings probably add a bit of harshness to my ride but I don't find it objectionable and it's a reasonable tradeoff for the added precision in the front end. I don't believe that the polyurethane steering rack bushings have any tradeoffs at all. The remaining shake that I'm experiencing is pretty darn subtle but I'm not done. I'm going to rotate the tires tomorrow and see if anything changes. I'm also looking at toe in. My front tire wear tells me that I don't have enough. I've been running factory settings but I'm going to experiment with a bit more toe due to the additional road forces created by the wheel spacers. I don't give up easily!

wbrewster

Bon: I have owned 3 high milage SCs. They all had this issue. My current SC is an 02 w/108K miles, very very well maintained by the last owner. I had all wheels professionally straightened, all 4 wheels Road Force balanced, new non-run flat tires. Currently the steering wheel does not shake but I feel a slight shake in the car most of the time. Very very minor. I am beginning to think that this is normal in the SC. I need to do to a dealer and test drive a 2101 model. I really love the SC. I think it is absolutely beautiful and given the car's body never changed over it's 10 years so it is a unique vehicle which seems to never age. Good luck to you. Thanks, Wayne

irokdastar

Did you have someone take a look at your suspention? Could be the spacer isnt on right. This happened to me once on my bmw . Take off the front wheels and make sure its sitting flush against the hub and wheel. It can also be your shocks.

cyberlexus

iTrader: (2)

7) Daizen steering rack polyurethane bushings. Ah Ha! This helped a lot. Still not perfect, but this made a huge difference.

I couldn't find this at sewell, can you share a link? How difficult is it to install?

Poqman

Here's something to consider.....I had a vibration I couldn't seem to get rid of until I realized my Bridgestone Potenza tires got flat spots when temperatures were below 60F in as little as an hour. I concluded this was throwing off my road force balance. Typically, I would drop the car off, it would sit for hours, thus developing flat spots. Then they would road force balance. The flat spots were seen as variations in the side wall stiffness and throw off the road force balance results. I went back and insisted that they schedule me an appointment so the car did not sit around with weight on the tires. When I arrived, they immediately lifted the car on a lift so the tires stayed round until a mechanic was available to do the balance. This way no flat spots would develop. They re-balanced and the vibration was gone at all speeds (well up to 100 mph anyway). If you have noticed flat spots with the Potenza's, it could be the reason your balance is off.

BTW, how hard was it to replace the steering rack bushings? My car has 99k miles. Did you find a write-up with instructions?

Bon

You're right the spacer can sure do this but it was happening before the spacers were added. However, I probably should wire brush the the spindle face. The shocks are on my list as well. I've only about 52K miles but they are showing a bit of oil. Not enough to shout "replace me!" but they're suspects as well.

I too believe that this is not just related to my car. I believe the shake is essentially "built in" to the SC. I really enjoy owning this car and I actually enjoy the journey of making it better.

I have noticed how quickly the tires flat spot. Just sitting over lunch and the flat spots are apparent when I jump on the freeway. That's a great way to work with your shop. I'll definitely do that the next time!

Sewell doesn't have the Daizen's but they do have an aftermarket polyurethane part. If you search for part number 207 you'll find it. I actually ended up owning both the Sewell part and Daizen. After looking at them both I installed the Daizen. I purchased the Daizen from TM Engineering. The install is rather easy. There is a good thread in the GS forum. It's a bit old but still a good read. It's here. I don't agree with all that you read there though. I believe that the rack bushings should be replaced period. My rack didn't "seem" to move excessively but the new bushings made a significant improvement. I'll say it again: I don't like the Lexus OEM bushings at all! I'll write up a short do-it-yourself sometime today. No pics though, sorry.

scdroptop

iTrader: (1)

Bon-

I've shared your experience on multiple cars over the years and honestly I've summed it up to the fact that some wheels on some cars (especially non OEM, replica OEM or aftermarket) just don't fit right. After all these years of having 3+ cars, I've also figured out that cars need to be driven more. All but one or two of my cars have had this problem with non-oem wheels and they have been garage queens. I really didn't start having problems with aftermarket rims/tires till I started getting into 20"s and 22"s about five or six years ago. In the old days, going from a 16 to a 18" or 17 to a 18 or 19 inch wheel gave me no problems. But, going from a 18" to a 20" or a 20" to a 22" has.

You've covered off on many of the common culprits of this problem:

Hub Centric Rings (and turned the correct way)
Torque correctly (by hand) the lugs
Center weights properly on the inside of the wheel
Road force balancing
Air Pressure
Poqman mentioned weather-I too believe weather has a big deal to do with it---I've had many TPMS lights go off as the temperature changes drastically.
Lack of driving/dead spots-this happens a lot
Tires sitting at retailer too long
P/S Rack
Struts
Tie Rod
Bushings
Wheels being non-true??? Hard to prove especially when you buy new wheels. I am convinced that some non-oem major mfg's of knock off wheels, replicas or re-chromed wheels offered on eBay could be non-true.
Wheel/Tire set bought online-be careful as tires could have easily been sitting for a long time.

I'll give you some examples of my personal situations...

Had a 03 Infiniti FX35 with factory 20's on it for three years-no shakes whatsoever. I got the itch to upgrade to NEW OEM 20's they had on the 2008+ FX's and new tires and dealt with shakes the entire time. Like you, my new 20" chrome OEM's I thought were new, but who knows...they wobbled from day one. I replaced power steering rack (found leak), struts, put in a strut tower bar and road forced balanced dozens of times. Changed to nitrogen air, etc etc. Nothing. They changed location of the weights to "on center" and this didn't help. Went to tape weights to the king you hammer in on the lip inside and back-nothing. This car was my daily driver, so I couldn't chalk it up to lack of driving/dead spots.

Had an 02 SC430 Alexa red/ecru when I got her, she had the accessory SC430 TRD wheels on her and I took them off and added 20's staggered brand new with brand new Dunlop Direzzos and she wobbled the entire time I owned her. I had it road forced many times, struts checked, power steering rack checked, bushings replaced etc etc. Nothing. Every time she was way out of RF balance and they corrected. Tried manually torque, machine torque, changed hub centric rings out, changed weight types, changed location of weights, tried different air (nitrogen) etc etc. Only would do it after not driving for few days, which was all the time since she was a garage queen.

My current two "fun" cars have slight wobbling. My 09 FX35 with 17k miles wobbles ONLY when I have a certain pair of wheels/tires in the front. I've tried all combinations and I THINK I've got it right. Only wobbles between 50-70 mph and both car/wheels/tires were brand new when I bought them and I have the hub centric rings, hand torqued the wheels to spec, tire pressure is good, tires are perfect, road force balance is WAY out of whack each time they put it on, but then they rebalance and I drive off and all of a sudden it wobbles again. I've learned to live with it, as I drive this car only a 3-4 days a week and I'm tired of chasing it.

My current SC has similar problem as the FX. Bought brand new wheels 20" and tires, hub centric rings, Discount Tire had manager and even regional manager look at the RF balance machine and hand torqued multiple times and I get a really erratic wobble after I don't drive the car for a few days (which is always) or change in weather. RF balance always shows it's off by 2oz or more in the front. I've had the Megan LP Streets added, realignments, re-balanced, air deflated and re-inflated with nitrogen and many other things like suspension etc looked at and to no avail!!! Wobble between 45-65 mph.

On my SC specifically, it gets better as I drive the car more/longer and more frequently. On the FX, it doesn't matter.

I've also gone to multiple road force machines at different shops as well as gotten dealership opinion. Dealer ALWAYS says "that's why we recommend staying with the OEM setup" and they also say that many of their cars they sell with non-oem larger wheels wobble from day one at the dealership.

On your replacement OEM chrome wheels, one possibility could be that they are take offs that were damaged, re-chromed (or new chromed) and sold by whoever you bought them from. I know you might not like to hear this, but I think there are plenty of outfits who do this and I know in fact of several that make a great business of taking damaged wheels or take offs, cleaning them up, chroming and selling online. It happens all the time. I think I've been a victim of this before. Have you ever just looked at your wheels spinning on the machine to make sure they are "true"???

Just a thought. If it makes you feel any better, I share your pain, bro! I ask the shops all the time, how a car can be road forced perfectly, then you drive it off and it starts wobbling. Also, how does a car sitting in your garage start to wobble with a temperature change? What's really funny is all this time I've had my fun cars or garage queens wobble my company car daily driver (usually some Chevy/Ford/Chrysler/Jeep POS product) has NEVER had wobble problems with their factory 16-18" wheels, LOL. Funny I take this car to the same place as my personal cars and never a problem with wobbles.

I've learned not to sweat the small things as much as just live with it, LOL.

Bon

All good stuff, scdroptop, I probably should have the wheels dial gauged to measure their radial and axial runout. I'd love to put that nagging suspicion to bed. Having this done with the wheels still mounted on the car finds bent spindles at the same time. I'm the second owner, so she's not a virgin, and I don't know how many curbs she's kissed.

I sometimes wonder if it's simply the lower profile tires that we drive? And the bigger the wheel the lower the profile of the tire. The ultra-short sidewall doesn't have much give in them. So imperfections in the carcass, tread, road and air pressure are transmitted easily through to the chassis without being absorbed by a flexible sidewall.

After I revisit the wheels and tires I'll consider replacing the shocks. If there aren't any more improvements I'll likely just wait until I wear out these tires and try another brand.

Bon

I had a Hunter road-force balance done on all four of my tires. I followed Poqman's advice and didn't let the car sit at the shop before they raised it on the lift. One tire was found to be 0.5 ounces off in balance. They fixed that and all was pronounced OK. My SC now drives like a Lexus should. It's shake free and the steering is precise. It's now a real pleasure to drive. Yes the tires will still flat spot after standing but when they warm up and get round all is perfect. All in all I just love the steering rack bushings as they have made the single biggest difference in my handling and driving pleasure.

Poqman

Bon, I'm glad I could help. I hate the flat spots that the Bridgestone's develop, but they do return to balanced after they warm up each day. Mine has stayed in balance for 5 months now. It was the third attempt to Hunter road force balance before I realized it was the flat spotting that was throwing off the results.

Now tell me, how hard was it to replace those steering rack bushings? An hour of labor? Do you have to drop the rack completely or just loosen? My ALLDATAdiy subscription doesn't tell me how to replace these bushings.

Bon

1) Jack up the front of the car and put it on stands.
2) Drop the plastic pan and x-brace to get access to the rack.
3) Remove the four bolts that hold the rack in place. The rack won't fall down but you can pull it down far enough to expose the two round bushings on the drivers side.
4) I used a large screwdriver and rubber hammer to bump the bushings out from the front side and pushing them toward the back of the car.
5) Install the replacement bushings. The aftermarket brand from Sewell and the Daizen are split bushings so they slip in from both the front and back. Lexus OEM bushings might be a bit more of a struggle but I've never done them. (Nor would I recommend using OEM!!)
6) The passenger side is far simpler than step 5 and will be obvious when you remove the rack.
7) Tighten the steering rack bolts back up to 40 ft-lbs (maybe 45?).
8) Reinstall the x-brace and plastic pan.
9) Lower the car and you're good to go.

I didn't have to remove the wheels or the steering column. There was plenty of wiggle room, of the steering rack, with the car on jack stands. The drivers side bolts are self tapping so they won't torque up well at all. I just used a pneumatic impact wrench to remove and reinstall them until tight. The passenger side bolts go in and out easily because they use captive nuts - piece of cake. Overall about a 2 out of 10, at most, for a DIY job if you have an impact wrench. Otherwise you'll need a 1/2" socket set with a cheater bar and plenty of elbow grease for those self tapping bolts. I ordered new bolts from Sewell and they were still hard to tighten. The old bolts will work fine.

mandyfig

Great DIY, would have been perfect with pics....but will take it anytime.

If I ever do this, I will post pics.

Bon

I'm warning you: If you don't do this asap you will absolutely hate yourself when you do! The improvement in steering precision and tracking is huge. My '06 SC has 53K miles and it was more than time to replace them. It's absolutely the best $30 you'll ever spend on your SC. Great bang for the buck. Just say no to OEM rack bushings!

Poqman

Bon, is this the bushing to which you are referring? I just want to make sure this is the split bushing you recommend before ordering. http://lexus.sewellparts.com/accesso...2002/4558.html

Poqman

Bon, you also mentioned that the SC and the GS had similar steering setups. Would you look at the attached link starting with thread #2 and tell me if this looks like ours?
https://www.clublexus.com/forums/sus...k-bushing.html Thanks for your help.