Wobbling issue

[GrayS550]

I’ve posted about this, but thought I’d go more into detail to rule out what else it could be.

When accelerating (both Full throttle and regular throttle) between 60mph - 80mph+, the car wobbles on acceleration. It’s a slight wobble as if the wheels are turning left and right a couple degrees, all while the steering wheel is straight, which makes it feel like I could lose control if I don’t release my throttle. It stops when I release my throttle, and starts up again when I accelerate.

My steering wheel is straight, but it still wobbles.
My wheels are balanced, no vibration in the steering wheel, alignment is perfect, still wobbles.

Could it be tires? The tread is really good on them, they have a lot of grip. When I drive regular city speeds, I don’t get wobbles so im guessing it’s not tires?

Could it be wheel hub bearings? How do I check and what would I be looking for if they’re bad?

Could it be struts? If they’re shot, what would I be looking for?

What else can I look for? My suspension has been checked out by 2 different shops, including pressure testing and everything checked out. Shop 1 was a local, well known muscle car shop close by, and the second shop was les Schwab.

Muscle car shop took it for a test drive and said it could be wheel hubs.
Les Schwab pressure tested my suspension and said everything looked good.

I haven’t had fun driving my car because of this issue.

2018 Mustang GT base package, 24k miles, SR Performance Sport Lowering Springs (the rest of the suspension is stock (bought the car like that)).

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[Rapid Red]

If it is the tires, simple to check that, rotate, and drive. If it changes, have them balanced.

 

[Andy13186]

Could be axle thrust washers. My car did this when mine were bad. Also had a noise when switching from drive to reverse or reverse to drive.

 

[Roadsign]

Loose axle nuts/worn rear wheel bearings will cause what you are describing.

 

[MidnightStars]

Make sure the roads you're on are in decent shape too.
I've noticed that on roads with fairly large cracks, bumps, etc., pretty much going the length of the road, they seem to grab the car's tires and pull you along those imperfections.

 

[Cobra Jet]

To check the wheel hubs (front or back):

- Get the car safely up on jack stands (or a lift).

- Grasp a wheel at the 12 and 6 o'clock position and pull the wheel towards you and push it towards the car. Do the same at the 9 and 3 position.

- There should not be any "play" when grasping and performing the above diagnosis. If there is ir there is excessive play, you need a new hub bearing.

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Be aware that S550's are known to have premature wheel hub failures. It's been well documented on this site that M6G members have experienced failures below 5k miles, and in some instances even with a warranty repair, repeat failure of the same wheel bearing that was replaced. No one knows why - whether it's improper torquing or the hardware, bad alignment, or just manufacturing defect of the supplied part. Some have had to replace more than 1 or all 4.

Some M6G members have not had any wheel bearing failures and racked up lots of miles.

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Aside from possible wheel bearing failure, I would make sure that the rear IRS cradle does not have any bolt or bushing failures. Yes, a shop can "look" at everything and it "looks" fine, but doesn't mean there isn't anything faulty. Quite a few M6G members have found that the differential bolts have snapped OR that the differential bushings have torn. These parts are not just a "looky loo, all is well".... The tech or owner has to actually inspect closely by physically inspecting those very parts for fatigue and failure.

I'd start with the wheel bearings first, then get under the car and really check out the entire rear IRS cradle and differential mounting points.

 

[NightmareMoon]

Agreed its most likely the rear wheel hubs, and following the procedure above should prove it.

Your car is 5 years old, and so its definitely due for wheel hubs to fail, unfortunately they are a wear item, and on these cars, the rears do wear out faster than most other cars.

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