Alignment problems?

[Daryl333]

17 GT auto
3:55 rear
295/265/35/20 new tires.
BMR Lowering springs.
BMR Cradle lockout kit.
BMR rear Chassis brace
My back end jumps to the right when going over small bumps(manholes etc). It's getting worse and almost feels like something is broke the deflection is getting scary. And when I went around a corner under throttle and hit a little bump It felt like it was ready to jump right off the road. I've had it inspected and aligned.
Nothing was found but since the alignment it feels worse. Can any suspension gurus give me any advice on what this may be? I put my alignment sheet up because I can't figure it out. And the alignment tech might have thought my car was a PP would this make a difference? Can anyone make sense of it? Oh and it only deflects to the right rear never left.
Thank you.

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[kz]

Looks good, actually someone did a nice job (assuming alignment rack is properly calibrate). It sounds like a blown shock in the rear from what you are describing.

 

[Brian@BMVK]

1) Check tire pressures
2) Were your suspension bushings re-clocked after you did lowering springs?
3) Check your outside toe-link bolts for proper torque (while the tires are loaded - this can be done with a 12" extension)

Could be a blown shock as well. Did you trim the bumpstops when you did lowering springs?

 

[NightmareMoon]

Your alignment looks good.

in addition to the above, I'd remove and inspect the rear shocks, a 2017 that's been driven a lot may need the shocks replaced by now. Inspect the bushings in the rear suspension for tears, and rear hubs for play.

Rear hubs which are failing will cause very unpredictable movements under load.

 

[Roadway 5.0]

Alignment looks great.

What’s the width and backspacing on your wheels? You have pretty large diameter tires and may be rubbing againt your struts, shocks/mounts, or fenderwells.

 

[Daryl333]

1) Check tire pressures
2) Were your suspension bushings re-clocked after you did lowering springs?
3) Check your outside toe-link bolts for proper torque (while the tires are loaded - this can be done with a 12" extension)

Could be a blown shock as well. Did you trim the bumpstops when you did lowering springs?

Thx for the replies.
My car only has 33,xxx Ks
so around 25,000 miles.
Bushings have been reclocked.
Tire pressure good.
No tire rub.
Am using 20mm spacers.
No excess heat or noise from hubs he checked that.
Bumpstops were trimmed according to install sheet
I live in Vancouver, Canada
and this alignment guy is the GO TO guy here, and he went over my suspension with a fine eye.
Said all bushings seemed fine but couldn't point out any non visible wear of course. But I will take my car back and get Toe link Tq. and Shocks checked. I actually thought it might feel like a shock altho I've only felt a broken spring before and this is not a busted spring.
Thank you for the help, any other parts to check please chime in it will take a couple days to get an appointment.

 

[Andrew@Lethal]

17 GT auto
3:55 rear
295/265/35/20 new tires.
BMR Lowering springs.
BMR Cradle lockout kit.
BMR rear Chassis brace
My back end jumps to the right when going over small bumps(manholes etc). It's getting worse and almost feels like something is broke the deflection is getting scary. And when I went around a corner under throttle and hit a little bump It felt like it was ready to jump right off the road. I've had it inspected and aligned.
Nothing was found but since the alignment it feels worse. Can any suspension gurus give me any advice on what this may be? I put my alignment sheet up because I can't figure it out. And the alignment tech might have thought my car was a PP would this make a difference? Can anyone make sense of it? Oh and it only deflects to the right rear never left.
Thank you.

Sounds like it may be time for some new shocks for the rear.

 

[NightmareMoon]

Have the shocks checked and check the /hubs/ for play. They’re easy to check and don’t always make noise when they start to go squirelly on you. The older S550s had a lot of premature hub failures. The newer replacement parts seem to be holding up better.

 

[kz]

Hubs are definitely good call. Especially that you can do that at home with a jack...

 

[NightmareMoon]

I had my first hub replacement under warranty at only 26,600 miles.

 

[Roadway 5.0]

Am using 20mm spacers.

Double check that these spacers are flush to the hub and torqued correctly, as well as the wheel to the spacer. If tire clearance allows, remove the spacers and see if the problem persists.

Otherwise, I defer to what others recommended.

 

[Daryl333]

Double check that these spacers are flush to the hub and torqued correctly, as well as the wheel to the spacer. If tire clearance allows, remove the spacers and see if the problem persists.

Otherwise, I defer to what others recommended.

Spacers were retorqued and checked 2 weeks ago.

 

[Daryl333]

Have the shocks checked and check the /hubs/ for play. They’re easy to check and don’t always make noise when they start to go squirelly on you. The older S550s had a lot of premature hub failures. The newer replacement parts seem to be holding up better.

I'm waiting for a call back from the suspension re: inpection of suggested failures.
Thx.
Update: Have an appointment on Thursday 22. This guy is busy.
How would I go about checking shocks?
Hubs just have to check for play?
Thx.

 

[kz]

I'm waiting for a call back from the suspension re: inpection of suggested failures.
Thx.
Update: Have an appointment on Thursday 22. This guy is busy.
How would I go about checking shocks?
Hubs just have to check for play?
Thx.

Unbolt the shock on LCA mount and see how difficult it is to move it ? If it moves easily, then it's definitely blown.

 

[NightmareMoon]

I'm waiting for a call back from the suspension re: inpection of suggested failures.
Thx.
Update: Have an appointment on Thursday 22. This guy is busy.
How would I go about checking shocks?
Hubs just have to check for play?
Thx.

Hubs - if you get the wheel off the ground and wrap two big arms around it to push pull and try to shift it. Its a big car and the wheels aren't light so its not as easy as it is to check for play on a small car. If it moves at all (obviously besides rotating) then its bad. If you're hearing any metalic pings at low speed accel or decel, that's also a sign.

Shocks - visually check for signs of seepage. If you take if off the car (only four bolts, leaving the upper mount attached to the shock) you can see if it seems weak. It should strongly resist movement, and shouldn't make knocking noises or anything like that. Note: Shocks that have been sitting for a long time may gurgle and be weak until they've been pumped a few times in an upright position. That's normal for shocks stored on their sides. A shock that's been on the car and driven recently shouldn't gurgle or be weak.

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