2001 740il - rear suspension "bouncy" but gets better with S-EDC - how to fix it?

[TireFryer]

My daily driver, 04 Caddy DeVille finally gave up it's ghost and I ended up buying a 2001 740il sport, TitaniumSilver w/ black interior - 122.5K miles - very clean car.

So, noticed it during the test drive, and confirmed it on the drive back home - rear end is very "bouncy" and at times almost sounds like it is bottoming out, but never did. However, when I turn on the S-EDC button (green light on), the ride becomes kinda okay - still not a BMW quality ride, but much better. Any ideas as to what is causing this and potential solution? I am new to the E38 platform, and am trying to read up on it, but any input from the E38 gurus would be greatly appreciated.

TIA

[TireFryer]

Looked under the car and the hardware looks nice and clean, BMW label/sticker still on the rear struts, so I imagine they might have been done at some point in time, but no records.

Any thoughts other than taking it to the stealer for diagnosis?

Thanks.

[Qsilver7]

If the rear shocks are "bouncy"...wouldn't that indicate that they have failed?

Even though the EDC shocks are electronic...they should not be bouncy. See the info below if you haven't seen it before that explains how EDC works (it is adaptive & automatic in that it will change on its own without driver input if road conditions & driving dynamics change):

[TireFryer]

This helps - thanks.

For those who have replaced their EDC suspension with non-EDC suspension, recommendations? This will be a daily driver.

[Raudi Driver]

I replaced with EDC and it's great. You can get the rears from the Huskers BMW parts for the cheapest.

[TireFryer]

I replaced with EDC and it's great. You can get the rears from the Huskers BMW parts for the cheapest.

Thanks!

[kulgan]

So reading that my 740i EDC rides hard(permanent sport mode) which would indicate a fault in the system.
The 728i I bought as a parts car has bouncy suspension indicating its worn out.
Correct?

[Qsilver7]

So reading that my 740i EDC rides hard(permanent sport mode) which would indicate a fault in the system.
The 728i I bought as a parts car has bouncy suspension indicating its worn out.
Correct?

Does the 728i have EDC, too? Or does it have a conventional suspension? If you push down on a corner of the car and the car bounces/moves multiple times before settling down, then yes, that shock/strut is more than likely worn out.

[kulgan]

Does the 728i have EDC, too? Or does it have a conventional suspension? If you push down on a corner of the car and the car bounces/moves multiple times before settling down, then yes, that shock/strut is more than likely worn out.

Yes, the 728i has EDC but they're stuffed. When I backed it off the trailer it felt like I'd driven onto a trampoline..lol

Bounce, bounce, bounce..

[xboss]

bouncy can mean that you need to replace the expansion tank bomb looking things. Are those on a car with EDC or EDC SLS I forget but my EDC has never bounced, it's just extra super firm.

[Qsilver7]

The "bombs" (pressure accumulators) are part of the rear SLS system...and yes when they fail...its bouncy like if conventional shocks/struts are blown....perhaps even worse.

You can see the 2 bombs (one of right side & one on the left side) in the diagram below:

[TireFryer]

Update; so either the previous owner installed or the person/shop who installed the rear controls arms wrong! The left was installed on the right side and vice versa.. and to do so, they were upside down! The bottom of the car was actually sitting ON the curve of the CA which was up rather than down (due to being installed on the wrong side!) Removing and installing them properly actually allowed the rear suspension to actually move as it should!!! Checking tomorrow to see if any of the rear bushings need to be replaced due to the wrong install of the CA! Bummed I didn't take pics! For now, looks like the rear EDC might be fully functional and not need replacement!

Sent from my SM-G920V using Tapatalk

[TireFryer]

So car is back on the road and I am happy to report back that the rear EDC suspension is 100% functional! Once the rear CAs were removed and installed properly (left on left side, and right on right side), the suspension travel was came and viola = BMW comfort ride!!!

Here is a pic of what installing the rear CAs on the worng side, upside down will do to the body as it sits on the CA. This is why I was experiencing the "bottoming" out! Still can't believe someone actually managed to to this!!

740il rear CA issue.jpg

[samsonevickis]

Lol, excellent thread. This was exactly my problem as well!

It happens to the best of us!