[bujbot]

Hi (first post here),

I was driving my new M2 the other day and while coming to a stop I heard two loud metal scraping sounds coming from the front. I took it in and the technician said that my front two shocks had slid about 1/2" into the steering knuckles. They said they have seen this before when someone runs over something big, or hits a large pothole. I haven't done either, in fact I baby the car. The car only has 1500 miles on it and just had it's break in service.

While under the car with the technician we saw no other damage anywhere else on the vehicle, and no scuffs or scrapes on the underbody. It's pretty shocking (no pun intended) as I was just expecting there to have been a rock caught somewhere in the brakes.

I'm still waiting to hear from the service manager/foreman to see if it will be covered by the warranty, but I'm worried that they are thinking I'm not telling the truth about not hitting something. I've told them they can pull the accelerometer data from the car to look for impacts. I've mainly used the car for trips with my family and no one remembers anything close to hitting something ... I'm definitely concerned about the cars reliability/safety if my basic driving does this level of damage and it wasn't a part/manufacturing defect.

Has anyone else heard of something like this?

Thanks so much. I've been searching the web but haven't come across others with something similar.

[izzyM2]

Disheartening! is it a 2024? Keep us updated.

[bujbot]

Originally Posted by izzyM2

Disheartening! is it a 2024? Keep us updated.

Thanks izzy! It's a 2023 picked up last June.

[RootsTootsMagoots]

Even if you did run over a pothole, that seems crazy to me that it would cause that issue. That's a normal road condition. What car breaks going over a pothole?

But the pot hole theory doesn't make sense. How could it happen to both sides of the vehicle unless it was a pothole to end all potholes?

And finally, if there's no other exterior damage, there's no evidence that you ran over a large object. What type of object has enough mass and a small enough area to displace the shocks but leave no damage? A black hole??

[aerobod]

Originally Posted by RootsTootsMagoots

Even if you did run over a pothole, that seems crazy to me that it would cause that issue. That's a normal road condition. What car breaks going over a pothole?

But the pot hole theory doesn't make sense. How could it happen to both sides of the vehicle unless it was a pothole to end all potholes?

And finally, if there's no other exterior damage, there's no evidence that you ran over a large object. What type of object has enough mass and a small enough area to displace the shocks but leave no damage? A black hole??

A speed bump taken too fast where the shocks bottom due to the bump being higher than the travel of the shocks. I'm not saying this is what happened to the OPs car, but it is a scenario that could cause this sort of damage. A worse scenario is the the shocks don't move in the upright and the towers distort or burst.

[bujbot]

Originally Posted by RootsTootsMagoots

Even if you did run over a pothole, that seems crazy to me that it would cause that issue. That's a normal road condition. What car breaks going over a pothole?

But the pot hole theory doesn't make sense. How could it happen to both sides of the vehicle unless it was a pothole to end all potholes?

And finally, if there's no other exterior damage, there's no evidence that you ran over a large object. What type of object has enough mass and a small enough area to displace the shocks but leave no damage? A black hole??

I hear you, RoosTootsMagoots. Thanks for the message, I appreciate it.

[bujbot]

Originally Posted by aerobod

A speed bump taken too fast where the shocks bottom due to the bump being higher than the travel of the shocks. I'm not saying this is what happened to the OPs car, but it is a scenario that could cause this sort of damage. A worse scenario is the the shocks don't move in the upright and the towers distort or burst.

I'm wondering if the shocks weren't properly seated in the knuckle and now they've slid into place. Doesn't the shock have two diameters that the knuckle mirrors? Otherwise, if the shocks were seated correctly and then slid further into the knuckle the knuckle would have had to split or the shock squeezed so tight the metal reduced in diameter. Which sounds crazy.

UPDATE: I found this video at this timestamp which shows the shocks pretty clearly. I spaced out and didn't take pictures when I was looking at the car with the technician but they said they will send me pictures tomorrow. I can compare how far the shock has slid to this.

[aerobod]

Originally Posted by bujbot

I'm wondering if the shocks weren't properly seated in the knuckle and now they've slid into place. Doesn't the shock have two diameters that the knuckle mirrors? Otherwise, if the shocks were seated correctly and then slid further into the knuckle the knuckle would have had to split or the shock squeezed so tight the metal reduced in diameter. Which sounds crazy.

UPDATE: I found this video at this timestamp which shows the shocks pretty clearly. I spaced out and didn't take pictures when I was looking at the car with the technician but they said they will send me pictures tomorrow. I can compare how far the shock has slid to this.

You can also look at any drop by checking the spring platform distance above the tyre tread, noise can be caused by the tyre rubbing on the platform if the strut drops.

The bottom of the strut has a taper on it for height location in the upright/knuckle. I think under a severe load where the strut bottoms, the taper section of the tube can be crushed and cause the strut to drop in the clamp. If this is the way the strut is damaged, I would be questioning the dealer about shipping driver damage, especially if they have hit a speed bump hard at speed with the shipping blocks still in place.

[bujbot]

Originally Posted by aerobod

You can also look at any drop by checking the spring platform distance above the tyre tread, noise can be caused by the tyre rubbing on the platform if the strut drops.

The bottom of the strut has a taper on it for height location in the upright/knuckle. I think under a severe load where the strut bottoms, the taper section of the tube can be crushed and cause the strut to drop in the clamp. If this is the way the strut is damaged, I would be questioning the dealer about shipping driver damage, especially if they have hit a speed bump hard at speed with the shipping blocks still in place.

This is really helpful information, thank you! I'm very curious to know if the shock has been crushed or not. Your comment about the shipping blocks is very interesting as well. I was looking at pictures of the car the day I got it vs a trip couple weeks ago that was right before I heard the noise and the camber looks identical (which I've heard will change if the shock slips). This doesn't mean the shock didn't slip after this trip, the next immediate trip was when I heard the scraping noise while braking ... still hard to believe braking the car would cause the shock to slip unless it wasn't properly secured or seated.

Thanks again for your comments and thoughts. You seem to have a lot of experience.

[bujbot]

Update:

I just heard back from the service department. The car was completely gone over by the foreman and given a full alignment. Alignment was still to factory spec (and they apparently tweaked it to be perfect). They feel strongly there is no damage to the shocks.

Looks like the original technician was a bit hasty in saying it had the shock damage, and the marks I can see on the youtube video that shows the witness lines about 1/2" below the bottom of the steering knuckle were what was giving them the impression (my assumption).

They think the sound was something lodged in the break pad (also my original thinking as it happened when I was braking) and it removed itself.

This is a massive relief for me, especially because I really have babied the car and was concerned that shock damage this early was a sign of a real reliability issue. I'll obviously pay attention to see if I hear anything or feel anything again.

Thanks everyone who offered suggestions/thoughts. I pick the car back up tomorrow.

[Chet for short]

Did the ride height change? If the strut moved into the upright, wouldn't it lower the ride height?

[bujbot]

Originally Posted by Chet for short

Did the ride height change? If the strut moved into the upright, wouldn't it lower the ride height?

I was thinking the same thing when I was trying to figure out what was happening. I looked at all the pictures I had of the car, from the pickup date to just before the noise and the ride height looked the same.

Not sure if you saw my update but the service team got back to me saying that the car didn't have shock damage. The marks the first technician saw that looked like the shocks slid in the knuckle are normal.

Happy to have the car back with the green light from the service foreman!

[RockCrusher]

Originally Posted by bujbot

Update:

I just heard back from the service department. The car was completely gone over by the foreman and given a full alignment. Alignment was still to factory spec (and they apparently tweaked it to be perfect). They feel strongly there is no damage to the shocks.

Looks like the original technician was a bit hasty in saying it had the shock damage, and the marks I can see on the youtube video that shows the witness lines about 1/2" below the bottom of the steering knuckle were what was giving them the impression (my assumption).

They think the sound was something lodged in the break pad (also my original thinking as it happened when I was braking) and it removed itself.

This is a massive relief for me, especially because I really have babied the car and was concerned that shock damage this early was a sign of a real reliability issue. I'll obviously pay attention to see if I hear anything or feel anything again.

Thanks everyone who offered suggestions/thoughts. I pick the car back up tomorrow.

Two times with my Boxster something got caught between the rotor and splash shield. One night on a road covered with twigs -- thanks to an ice storm -- as I was u-turning a horrible sound came from the car. Figured something caught in the brakes. Managed to dislodge the whatever.

Second time at the office (in Hayward CA). Got in the car and backing out of the parking spot heard a horrible screeching noise. Tired some steering wheel lock to lock turns while driving forwards/backwards to dislodge the object but was unsuccessful.

Had to jack up the right front corner of the car, remove the wheel, and pry the splash shield away from the rotor a bit. Tiny jagged rock fell out.

During a sharp turn the inside brake hardware is a bit exposed to something coming off the tire. Pic below. No pic of my M2 but suspect
its front wheel positions would look similar to those of the Boxster

[bujbot]

Originally Posted by RockCrusher

Two times with my Boxster something got caught between the rotor and splash shield. One night on a road covered with twigs -- thanks to an ice storm -- as I was u-turning a horrible sound came from the car. Figured something caught in the brakes. Managed to dislodge the whatever.

Second time at the office (in Hayward CA). Got in the car and backing out of the parking spot heard a horrible screeching noise. Tired some steering wheel lock to lock turns while driving forwards/backwards to dislodge the object but was unsuccessful.

Had to jack up the right front corner of the car, remove the wheel, and pry the splash shield away from the rotor a bit. Tiny jagged rock fell out.

During a sharp turn the inside brake hardware is a bit exposed to something coming off the tire. Pic below. No pic of my M2 but suspect
its front wheel positions would look similar to those of the Boxster

Thanks RockCrusher (relevant name ) thats a great perspective! I suspect you are right, I wonder if I was turning when a little pebble got involved.

[RockCrusher]

Originally Posted by bujbot

Thanks RockCrusher (relevant name ) thats a great perspective! I suspect you are right, I wonder if I was turning when a little pebble got involved.

Maybe but the risk is something can fall down even if the wheels are not turned. The high performance tires on my Porsche cars and now on my M2 are pretty sticky when hot. Driving through a bit of a pebbly parking lot or on a pebbly road I can hear stuff coming off the tires.