Hello all,
I have 2008 Lexus GS350 AWD with 122k miles on it.
I am reaching you guys again to address Bump steer issue. I really need your help.
I have changed the following part on both front sides:
1- Upper and lower control arms.
2- sway bar links
3- ball joints and bushings.
4- shocks with KYP brand.
I still have bump steer issue.
Is there anything else need to be fixed or changed to fix this issue?

thank you in advanced.

 

Try changing out your tie rod ends. warn tie rods can cause clunking/rattling/knocking also shakey loose feeling steering.

 

Common problem for these 3GS is the front lower rear control arm bushings. Its the big round ball bushings that hold the front lower control arms. If these wear and they are common for them to wear, they will allow the car to bump steer, especially over bouncy uneven roads.

Also the parts you replaced with were they all oem replacement or cheaper aftermarket? Actually the suspension on our cars are really good quality compared to many other car companies. im at 240k miles and still have some original suspension bits that are still good.

 

Yes, I have replaced these part as well.

 

I have changed all the front suspension part with OEM. No change
I am about to check the rack pinion and see.

 

If you replaced all the suspension bits with oem and everything is installed correctly. Then I would look at the alignment, there are adjustments that you can do to help lower the bump steer. You can also play with tire psi in the front, maybe your front tire psi is too high

 

are these okay as replacement parts for that issue?

 

To be honest, I changed all the front suspension kit including the struts and still have the same problem. The only part I have not changed is the Rack Pinion because I do not want to spend more money on it.

 

I'm wondering is this is just a build flaw with some of these cars. My car has always always been prone to bump steer and the front suspension feeling a bit squirrely, even after replacing suspension parts.

 

I'd say there's something weird, mine was perfect for years, basically drove itself on any surface (bumpy, uneven, dirt, etc) and I drove the heck out of it without issue. Almost literally in one week or so it started to pull either way, no favoritism, on any bump, ridge, frickin' tar lines - not exaggerating. It's a mystery that seems to have several potential causes, but seems to gravitate towards rack and pinion or ball joints and control arms. I have yet to find a mechanic that actually knows enough about Lexus to even diagnose it. I haven't tried very hard, because the last one wanted 750 bucks to change my plugs, told me he couldn't recreate the problem, and they were supposed to be super experienced, "expe" nsive it turned out. A lot of people do everything else, starting with tires and get to rack and pinion and don't want to drop the cash. It's a good likelihood because it has a computer thingy that tells the steering wheel where the wheels are or something. The one that sounded like the best solution was to have a Lexus suspension certified mechanic look at it and diagnose it, but if not, replacing pretty much everything made of rubber, which I am skeptical about, and the ball joints, tie rods, etc. - the funny thing is that I think it could be a minor bend in something that then infects everything else, and if you have dynamic steering assist or anything like that, which I'm not 100% sure of on the 3gs AWD - I have an 11, then it starts working against you and gets confused. So, even if you replace everything, if you don't find someone with techstream or an obd active systems gadget (900 bucks at harbor freight, but it looks like they work, car care but used one - how I got hooked on the car care but on YouTube) to recalibrate/reset your steering system computer, then it doesn't matter because your ****ing car is still confused so it works against the fix and you end up selling it or hitting yourself in the head with a hammer because you must be crazy and it was always like that or something. But it wasn't. Trust me. They are perfect, and should be perfect, and dealerships are not always knowledgeable about it, so it keeps being this crazy voodoo thing that is a hot topic on the forums to this day. If I find a reliable fix for it I'm going to open a home shop only for that problem and charge a reasonable "parts plus a thousand bucks" to cure crazy Lexus gs350s. I don't think I've heard of many other models or generations that get it. I've also heard of master techs dodging the diagnosis on cars under extended warranty because the fix is a PITA. Not sure if that's true. But there are several threads that cover the "phantom wobble" and tech stream plus the stuff that holds your wheels plumb and still seems to be the thing you need to do. Start with a lift and wiggle everything real good to see if it moves too much, then take it to a decent shop with road force testing equipment to see if there's a wobble from something bent, then test your steering rack, and if it's not bad or bent, replace all that stuff that holds your wheel on, get an alignment from a good shop with lasers... And one last time for the cheap seats - figure out how to get your computer reset and recalibrate the steering and suspension systems. You can pirate tech stream and Amazon and eBay sell dongles which the vendors of "definitely will not help you get that free copy of Heckteam working on your Blu-ray player"