Alignment question - not exactly Pro-Touring.

[BA.]

My 99 Lexus GS400 has become kinda twitchy after the DAIZEN poly-urethane bushing installation and subsequent front-end alignment. It definitely has not done this ever before, even through two sets of tires.

I'll try to post the current alignment spec sheet below, but what it feels like it is doing is following every road irregularity. It makes it kind of "darty" or "twitchy". Hopefully that makes some sense. It's at it' *worst* when changing lanes. Toe in/out ajustment perhaps?

It can do it while driving straight down a road also, it just seems to depend upon road conditions. There are a RARE few roads where it doesn't exhibit the problem, but most roads around here have typical mid-west, high traffic issues.

The weird thing is that I did NOT have these issues on the same tires just before the bushing swap. Too bad I don't know what the alignment was at beforehand either!


Any idea's?? It's driving me NUTS!
(oh yeah, the 'before' stats on the paper are out of whack because it's immediately after swapping bushings, balljoints, and tie rod ends)

[baz67]

The specs seem alright and are within the spec range given. The only thing that comes to mind is the only thing that was really changed on the chassis. How different are the new bushings from the old? Are the old ones rubber or poly? Has anyone else who has put the same bushings on their car had the same issues? My WAG is that to poly removed much of the compliance out of the system thus creating your problem.

[BA.]

The old ones were indeed rubber. Plenty of it in good ol' soft cushy Lexus fashion too.

I talk with some guys at a Lexus forum and dozens of them have done the bushing installation but so far, I've never seen anyone complain about this symptom I have.

When you lower a car...mine has had Eibachs for about 2 years,...should you adjust your settings a certain way? eg. more towards one end of the factory spec. range.

I'm also curious whether my alignment might have changed since the setting. (doubtful, but I wonder) I should probably get it re-checked. :-/

[baz67]

I agree with you that a check of the alignment may be in order. However, the guys on the site in the links have some valid thoughts. Try rotating the tires first. If that does not fix it then look at your toe angle.

[sinned]

My guess is that you have a set of tires that are more prone to tramlining than before, you may not have noticed it before as the alignment seems to have been WAY off and was probably masking the problem. Toe out has a tendency to hide drivability issues as you wind up scrubbing the tires down the road.

[chicane67]

Do you feel it more in the FE or the RE ??

What sticks out to me is both the toe settings. But because the FE shows more change, because its was a measurement just after the swap, makes more sense.

But... what bushing exactly were replaced again ??

With the softer durometer of OE rubber, it most likely that it wasnt that critical. But with a major increase in durometer it will exaggerate any effect or change in the alignment.

Its primarily toe and accerman, that make it hunt the grooves in the pavement... and any bumpsteer can and most likely will exaggerate that even further.

But since you just changed a plethora of parts and the slop (if there was any before) are now gone... it looks like you might have to tweak it until you fin its sweet spot again.

[MonzaRacer]

OK so after I stopped laughing I can see some things that you better find a better shop if you lookat the readings it looks like either the tech reduced the camber on the right or his heads slipped as it went way negative.
I usually dont see that much change even if the toe was off that far.
Ill have to lookand see if the Caster can be modified as its split wrong and I really dont like split camber regardless of what other techs say all I ever had doingthat was big trouble.
Another thing is this car lowered in anyway?
Oh and I forgot to ask was this done on a Hunter set up with strings, electronic heads or did you see it have flashing cameras up on a post in front of the car?
Ill look up the actual specs and try to post them here for you so you will kjnow what prefered is too.
I hate it when tech will just look at it and if its "in spec" its out the door (not to say this is your case) but I would also make sure you have atleast 1000k on it before a recheck to settle the bushings.
I hope I can get my scanner to work so I can scan stuff soon.
Hope it gets better and Ill see what I can find out.
Lee Abel

[Vegas69]

I think it sounds like a tire problem. You may have worn your tires to the point that they don't react well to a proper alignment. Run your hand across them and make sure they are nice and flat.

[BA.]

Sorry for the holiday delay!
I rotated the tires front to back and still exhibited similar problems.

I felt it mostly in the front end, via the steering wheel. It was an odd feeling actually. Feeling the wheel move with every road irregularity. Weird.

The bushings I had replaced were the UCA, the LCA and something this car has called a "caster arm" or "LCA 2". It basically runs from the LCA diagonally towards the center/back of the car, attaching at a spot on the floor.
The car was lowered long ago with Eiback 1" springs and new Bilstein shocks.
The bushings do have a couple of thousand miles on them now.

The toe was so far out after the bushing change that the car was a bit hard to steer. Especially in the rain!

An old Sears wheel and tire shop did the alignment and I recall seeing the car on a lift, with a readout on large posts up front.


As I had mentioned (I think), I needed new tires anyway so I went ahead and got those before the holiday traveling and LOW AND BEHOLD my problem seems fixed!!!

I'm shocked. Never would I have guessed that this was the *only* problem, but, the ol Lex performed very well for over 250 miles this past weekend.
All 4 old tires did exhibit visual camber wear for what it is worth.

I also got the Hunter 9700 (?) Road Force balance for these old 17" steel wheels. This is the first time the car has had NO vibration since I bought it 3 years ago. (through 2.5 sets of tires and the new bushings)

Thanks for all the help and idea's guys, this was driving me crazy.

Monza, I'll keep an eye out for your follow-up.