jdmboyee

Maybe someone can shed some light here i have had a highway vibration from speeds 50-80mph i know theres threads on this I've read them and used advice and repaired everything in the front end its so annoying and this money pit is almost full heres a list of what i replaced this year:
(Its lowered on megan racing coilovers)

All these parts are for both driver and pass side:
Lower ball joints and control arms
Upper control arms and ball joints
Inner tie rods and outer tie rods
Caster/radius arms
Steering rack polyurethane bushing kit
New brake rotors and pads
Alignment
New staggered 19" adr wheels
New nitto tires

**The shake is minimal now but enough to bug you**

I ordered new motor mounts and trans mount (not installed yet) just because i wanna rule out everything its a 2001 so 15 yrs old guess cant hurt right?
I know lowered cars wont be super smooth unless on air ride but back in the day my slammed integra rode smoother I'm about ready to sell this thing and move on... Help

jdmboyee

I forgot to add i have no play in the steering wheel or tires everything's tight

GS400V8

iTrader: (4)

If tightening your steering rack pre-tensioner does not help, which it did for me, I'm willing to bet the problem could be your aftermarket 19" wheels. Lexus wheels need to be hub-centered. If your stock wheels had vibration as well, and nothing is worn in your front suspension, the steering rack pre-tensioner might need tightening.

jdmboyee

Thanks for the reply this is the first ive heard of a steering rack pretensioner i will have to look up location and how to tighten it thanks again hope its that easy to fix this issue the wheels are new i ordered hub rings for the perfect snug fit from
Rim to hub ill try the pretensioner tonight thanks

GS400V8

iTrader: (4)

I will post a link below that shows you how to do the 2001-2005 models. So many people said you could not do this on the 1998-2000 models, but this is not true!

My car is a 1998, and instead of a wrench and nut needed to adjust the 2001-2005 models, I just used two wrenches.

I used the biggest adjustable wrench I could find at my hardware store, I think it ended up being around 2". The other wrench I used was somewhere around 1".

My car is lowered 1", and it was very easy to still crawl under there to do this. It took me maybe about 5 minutes, not including test drives in between different tightening levels. Excellent adjustment to do.

You can let me know if you have any questions at all.

Link: https://www.clublexus.com/forums/gs-...djustment.html

jdmboyee

Thanks alot im going to tackle this tonight

badblackgs

iTrader: (1)

wouldn't hurt to inspect your driveshaft center support bearing. you have to remove some of your metal shielding plates to gain access to it. and make sure the u joint is ok and doesn't have play in it.

bilgen

iTrader: (3)

This is gonna sound weird but my 01 gs300 had vibrations at random speeds due to one of the drum brake shoes for the e brake breaking loose. Annnnnd I have replaced most of the same things you have already. It's worth a shot to unbolt your rear calipers, yank the rotors off, and check your drums.

GS400V8

iTrader: (4)

Of course! Excellent advice as well from above, it would be good to check this while under there. I have heard of center support bearings going bad, as well as the Ebrake drums looking like they have self destructed when inspected.

jdmboyee

Thanks guys i will inspect those tonight i tried getting that lock nut loose of course no luck there lol but im gonna have another go at it tonight with this huge adjustable wrench i borrowed from work.

jdmboyee

What would a bad center support bearing look like ? Feel like? Do i try n shake the driveshaft by hand?

jdmboyee

I looked up some videos of people mounting camera under there cars and driving you can see the shaft shaking in my case my car is pretty low my luck id crush the camera

jdmboyee

Ok new dilemma..i jacked up my front end to check my wheel bearings .. I spun the rim and noticed my tire looked as if it has a flat spot like a up and down wobble to it (not happy these tires were a fortune) are my full coilovers bad? No clunking that i can hear when driving and the wheel spins freely no noise for bad wheel bearing

GS400V8

iTrader: (4)

If it looks like a flat spot across the whole width of the tire, I'm not sure if coilovers would do that, as that usually wears the tire in camber angles such as inside or outside the tire. Flat spots can occur when you are really hard on your brakes, they lock up, and shave the tire on one spot.

jdmboyee

Bad wheel bearings?