[itsbrokeagain]

I figured this would be the first place to post this up. I recently had a customer who came in to get his H&R sport/koni yellow suspension overhauled after 4 years and about 50k miles on it.
This is an E90 330i, strictly street driven and not driven hard at all. We pulled the springs in favor of HP Autowerks' Swift Spring coilover conversion. Upon disassembly we found the front struts holding up ok, but the rears were worn and no longer holding their own. After some trial adjustment we found that they had been set to full soft from day one and left that way, and carrying more than 2 people in the car just overtaxed the rear suspension. The bumpstops were noticeably worn from being slammed into, and the customer had mentioned he started hearing a creaking noise from the left rear.

We checked over the rear, finding nothing out of place, but on the left rear i noticed a bit of rusty dust accumulating around the shock tower. A quick inspection with a mirror revealed that the shock tower was starting to crack.

I will be putting up pictures shortly of this, we have 4 new shocks coming and to get to the shock tower i will have to section the metal out and clean it, followed by welding it back together.

I have reason to believe leaving the shocks underdamped led to this condition, but anyone who has a lot of miles on their car with a lowered setup, or rocking springs on stock shocks should have it checked out. I know the E36s and some E46s suffered bad from this, I would hate to see this starting to be an issue with these cars as well. I would also assume that this would include people who roadrace or autocross their car frequently.

Hopefully this will be an isolated incident

[itsbrokeagain]

Here are a few..

[Flyer]

Very good info!

[Sparky66]

Great detective work Matt........looking forward to your fix and possible preventative measures to prevent this issue.

[Bakeme521]

Thanks for the info, I have 42k on the clock and have been on h&r sports for sometime now. I was actually thinking to myself I am going to think into upgrading my suspension soon.

[Bimmer335i07]

Great find! I'm hoping this is only an isolated incident.

I'm going to bring my car to you in a couple of months to upgrade my suspension!

[e90pilot]

Yikes, I just cracked 148k! Gotta make sure I'm ok. I'm on Dinan Stage three which uses Koni yellows on Koni springs I think. I forget when I got it all installed. Good to know and thanks for the info!

[IN54NITY]

Crack!? Is it at 2:30-3 o'clock in that photo, or is that overspray? The rust sucks, too. Kudos for finding it. NaCl == BMW rear shock tower's bane from as far back as even the 2002 era.

[roundle]

Not able to "see" the crack. Could someone circle it in red?

Konis shot after just 50K? Weak. I've had Bilsteins last well over 100K...

[Gavin@MMW]

Great.. Thanks for making me nervous Matt, now I have to rip the car apart to ease my OCD - LOL

[Me_Hi]

Hmmm... I wonder how fat the 2 people carried in the back seats were....

[itsbrokeagain]

Originally Posted by roundle

Not able to "see" the crack. Could someone circle it in red?

Konis shot after just 50K? Weak. I've had Bilsteins last well over 100K...

The issue stemmed from being pushed into the bumpstops repeatedly from the shocks being set too soft.

On further note I have another client who is experiencing the same noise...hopefully it's not the same result.

[Chowbow]

Those have always been weak points on BMWs but the rear towers are different from the E36 and E46s. I wonder what kind of solution there will be long term to prevent these structural problems. This is the first I've heard of it though.