Source
FFJosty•

That’s a lot of lateral swaybar movement and inbound tire wear.

I would suspect very worn control arm bushings or lose control arm hardware. You said they replaced one bushing on each side that was worn badly, but you have 4 on each side, all likely had similar wear.

Really bad alignment could cause this too, I would have a different shop check it out.

2
StatekOP•

That was right before I got new tires, and the car is lowered so I'd expect some inner tire wear. I checked the other bushings (quick glance/tug just now) and they look fine, but I guess I might just have to check out another shop.

1
FFJosty•

Get it up in the air and use a nice big bar to try and move some components.

I’ve had lose control arm hardware cause that exact symptom. I was trying out various bushing/bar setups on my Auto-x car and forgot to torque them.

It would feel fine to a certain point of steer in and then try and throw me into a wall.

2
StatekOP•

Good to hear that its not an unheard of issue, I'm hoping the shop I went to just forgot to tighten some bolts, since it started happening immediately after their first alignment.

1
pineapple_calzone•

4 on each side

Six, plus the trailing arm, which could allow toe changes.

1
pineapple_calzone•

Check these four bushings, stick a pry bar in there and see if you can get them to move. They should be able to move, but not very much, and not very easily. They should be able to hold the suspension components pretty much in place while experiencing the sorts of huge forces you'd expect in a car's suspension, and only really move enough to absorb shocks and vibrations.

There's also an upper control arm you can't see in this photo, and a trailing arm, going from the front of hte knuckle to somewhere near where the lift is in the photo. Consult this and this for a better picture of how the suspension is set up. Check all those bushings. You're gonna find play in at least a couple of them. Replace as needed.

One thing I can say for certain is you're running very excessive negative camber or you have a toe problem, there's extreme tire wear on the inside edge of the tire, and the outside looks brand new. So you definitely need an alignment. If you don't find a lot of play in the bushings I marked, get an alignment and see if that fixes it.

While you're at it, check the bushings in the front suspension as well. If the rears are going out, it's a good idea to check the front as well, you'll likely find wear there too.

2
StatekOP•

Thanks for the info, I'll try to get under it and see what I can make move. The front definitely needs bushings too, but I've been holding off on that because it feels fine other than a light clank on bumps and starts (if I bog the engine into first) on both sides, and I'm not sure what I'd need to replace to fix that.

1
pineapple_calzone•

That could be suspension bushings but it could also be motor mounts

1
StatekOP•

It happens on bumpy roads and all with constant speed/acceleration

1
pineapple_calzone•

Only way to tell is to start sticking pry bars in things and checking. There's an anti-torque mount coming off the back of the transmission or the engine, going to the front subframe, that's typically the first thing I check when it comes to motor mounts in transverse mounted engines. You'll be able to check that when you're looking at the front suspension.

2
AutoModeratorMOD•

Thanks for posting on r/MechanicAdvice! This is just a gentle reminder to review review the rules. If you are here asking about a second opinion (ie "Is the shop trying to fleece me?"), please read through CJM8515's post on the subject. If this post is about bodywork, accident damage, paint, dent/ding, questions it belongs in r/AutoBody or r/Diyautobody If you have tire questions, check out r/howsmytire and ask there.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

1
StatekOP•

The best example is when hastily merging on a highway, lets say to the right lane, I'll turn the wheel to the right, I'll feel the car start turning to the right as normal, then I'll feel the rear kick out as if the rear wheels are turning left. I'll straighten out the car, then after a brief delay, it'll snap back into place. At lower speeds, the car acts normal, but it starts becoming noticeable above ~45mph if I make any remotely sudden or sharp turns.

If I'm driving in circles at a roundabout and slowly speed up, the car will act normal until a tipping point where the rear gives out and almost simulates oversteer.

This happened right around when I got new tires and an alignment. I took the car back and my rear left trailing arm bushing was completely dead, so they replaced it, realigned the car, and everything was normal for a few weeks. The problem came back, and then I got the right side bushing replaced (it looked fine but I wanted to be sure, and did it without an alignment) and it didn't change anything.

Any thoughts on what it could be?

Its possible that its coming from the front, but it at least feels strongly like its coming from the rear, especially from the delay after any sharp maneuver, but I don't see anything that looks loose or bad back there. There's something in the front that clunks a bit when going over bumps, but I don't think it's related.

1