99 GS4 with 140k. I changed pretty much the whole front suspension but I still get the steering shake at 65 and it pretty much goes away after 70 MPH. Especially going on the highway over uneven roads or when it’s windy the car legit pulls to the left and right. I had alignment done a few months ago and tires only have like 15k on them. My last GS was like this as well and the alignment would always go out but I do remember having to buy new rims since I couldn’t get the shakes to go away. Do you guys think it’s the wheels or possibly tie rods? I would think tie rods wouldn’t only be felt at those speeds. If I recall on my last GS when tie rods went bad even at slow speeds any bump jerked the steering wheel. The car is solid unless you hit over 60 MPH on an uneven road. Tie rods are new but the only aftermarket part on my car since the guy changed them right before selling me the car. Also to mention, my mechanic showed me the fluid was leaking on the steering rack. That bolt was all wet. Not sure if the steering rack could be the culprit as well. The way it only happens at like 61-66 mph has me leaning towards the wheels, either improper balance, alignment went out or tires somehow

 

Could be a number of things. Warped rotors can cause steering wheel shaking. What's the condition of the bushings on the control arms?

 

it doesn’t happen when I’m braking and I just replaced rotors recently so I doubt it’s that. Usually rotors only shake when you press the brakes. I’ve replaced all the control arms in the front practically so I don’t think it could be that.

 

When was the last time the front wheels/tires were balanced?

 

If the rack is wet, the rack bushings are possibly swelled/deteriorated. This would make for an increasingly uncontrollable feeling as speed increases. It doesn't sound like a tire balance or bent rim issue to me, because you usually start feeling balance issues at 35-40 and worse from there, and a bent rim even as low as 15-25. The car should be given a shake down. Jack up the front and feel for up/down and side/side movement. See if you can move the tie rods or the whole rack itself from bushing play. Everything needs to be tight to feel stable at speed. Check for bearing play and ball joints as well. You will need to jack from the lower control arms to unload the suspension on this setup. Then move the wheel up/down to see if a upper or lower ball joint is loose. I use a pry-bar between the ground and tire and pull up to get the most obvious movements too. But you will want to jack up from the center on the cross member for the rack check because you need both sides off the ground to feel for rack bushing play. If the rack can be moved inside it's mountings, obviously the bushings need replaced, but then you also need to consider what is getting them so soaked and fix the leaks you have. Don't forget about the rear. There are also bushings, joints, and bearings back there as well. I've had CV axles cause terrible vibrations as speed increases and center carrier bearings on driveshafts. But I'd think the issue is in the front end if you get wandering/pulling.

 

In those 15k miles, did you rotate and/or have them rebalanced?

 

Using power mode helps a lot as well but it definitely is noticeably looser with play in the steering wheel at around 62-65 mph. Once you go above about 70 the steering wheel tightens up nice. I’ve checked all the bushings and anyway they are new for the most part since I’ve replaced most of the front suspension. I do notice the front tires are worn unevenly from when I was previously driving with a bad alignment so maybe it’s the tires or the balancing got knocked off because it drove so much better right after the balance.

yea I just recently had the rear balanced and swapped out with spare rims I had in hopes it would solve it and it was great at first. Fast forward a couple months and potholes later it’s loose steering but mostly only on uneven roads and at about 62 MPH +. When I first got the balancing it definitely felt better.

 

Just to update this thread for anyone who might come across this, new OEM steering rack bushings solved this.

 

Thanks for the update! Where did you get the bushings from?

 

Thanks

 

my spot for oem parts. Discountpartsmonster.com. I always check and compare to eBay and other sites. 95% of the time they’re the cheapest! You can use discount codes. If you search Reddit discountpartsmonster there’s some small shipping discounts on there

 

i have this exact issue, i thought it was my wheels that were bad. I had it re-balanced and the shaking is still there. Do you mind posting the part # of this brushing? I was looking at it, and there's a No.1 and a No.2? Or am I looking at the wrong part?

 

get 2 (part #45516-30060) and 1 45517-30050 . Changes the whole car. I have to say these made a bigger difference then any of the controls arms I’ve changed so far in regards to the loose steering on the highway. The part ending in 30050 isn’t as important as it’s just a piece of rubber but the other 2 are what cause the loose steering