E39 Sedan rear suspension levelling

[hunter 408]

My E39 (like my E46 before it) has a ~9 - 10mm difference in ride height between left and right, the right rear being lower.

I know it's "normal" and according to BMW "in Spec" and probably due to gas tank, battery and driver all on the one side, however it bothers me.

On the e46 I had a local suspension shop make a spacer for the spring (which is seperate from the shock) in the E39 the shock and spring are configured in a "coil over" set up, making it a bit more difficult (?)

Has any one resolved the issue described above? IE  i'd love to get a 9mm (edit) of lift with a spacer in their somewhere to level the rear out.

I dont have the desire to go to coil overs.

 

Edited April 27, 2021 by hunter
clarity

[Allanw 1072]

Nah, it makes it easier:

You can buy "rough road version" rear upper shock mounts, with longer studs fitted (you can also fit longer studs, but why not replace the mount). BMW had factory fitted spacers on the top for rough roads.

I machined up a plastic spacer to go on the top, to lift our E39 with the Mtech suspension.

Be aware, that you probably only want a 5mm (maybe 6) spacer to lift it 9mm though??? rough enough is probably OK anyway - it's always going to be a bit either way, depending on load etc.

I think I used 10mm spacers and got maybe 16 or 18mm of lift??? - the suspension pivot is about halfway between the outside of the wheel and the inner arm mount - mathematically, you'll get double the lift for the spacer thickness, but the leverage reduces it slightly.

[hunter 408]

11 hours ago, Allanw said:

 

You can buy "rough road version" rear upper shock mounts, with longer studs fitted (you can also fit longer studs, but why not replace the mount). BMW had factory fitted spacers on the top for rough roads.

I machined up a plastic spacer to go on the top, to lift our E39 with the Mtech suspension.

 

yeah cheers, @Allanw i did a bit of research on the rough road version but cant see how much taller it is than stock anwhere, have asked my local dealer if they know.

Where did you sit the spacer you made? right at the top of the assembly? mine has M Tech 2 suspension . 

[Allanw 1072]

Yeah, my spacer just slipped over the studs on the top mount. It was much thinner than the rough road version.

Once you have the long studs in there, you can adjust thickness easily... but it just takes a bit of time  lower the shock/spring assembly after removing the rear parcel shelf.

Entirely from memory, the rough road version raises it 22mm???

I also raised the front of ours, which was a 10mm alloy ring, tapped so the studs were replaced with bolts, bolting the top mount to the spacer, and the extra length of the bolts from the studs to bolt it to the shock tower (plus I had a cheap strut brace to reinforce the soft shock towers). You can't get away with that on the back though, I don't think the bolt heads fit? I also wanted to make it all, before stripping the car anyway. You *may* be able to find replacement studs the right length, but the knurled part isn't always a standard diameter.

I don't have a pic of the back, but this is the front, same basic idea, just slightly different execution:

And this one is of it raised, which I don't think I quite achieved 20mm from original:

[hunter 408]

Thanks Allan. Good info. 

[hunter 408]

one thing i might try, is to get the left and right suspension swapped over to see if that levels it out theory being low vs high with weight on the swapped high side. 

[Eagle 1680]

Are you still on the original struts? 

[hunter 408]

1 minute ago, Eagle said:

Are you still on the original struts? 

Yeah mate. M sport 2. Quite expensive to replace so I’m wanting to try a few thing unless they are obviously shagged. Coombes checked a year ago at they reported no issues. 

[Eagle 1680]

Probably are from my pov knowing what a refreshed E39 feels like. The strut mount rubber can compress over time along with the strut dampening weakening which can lower you.   

[hunter 408]

Hmm ok. I’ll re measure myself and compare to previous measurements from last year. If it’s dropped further that’ll tell me. 
 

[hunter 408]

On 4/30/2021 at 6:19 PM, Eagle said:

Probably are from my pov knowing what a refreshed E39 feels like. The strut mount rubber can compress over time along with the strut dampening weakening which can lower you.   

Height hasn't chnaged but is still uneven. i removed the wheels today to visualy inspect for obvious differences eg diff shocks. none seen other than both L and R rear guide links have torn bushings / boots so need replacaing. that also probably explans the loose feeling in the rear end / feeling or extra rotation when going around tight corners ( the car feels like its often slide when its not is the best way i  can describe it)

I do plan on swapping the shocks from left to right as mentioned above, while im doingthis i wil also replace all the bump stops and strut top mounts etc,

Cheers

 

Edited May 8, 2021 by hunter

[Eagle 1680]

I would be replacing the struts with Bilsteins etc at the same time if you are going to strip everything down. Seems like a lot of work to do just to keep on using the originals which are most pretty worn at this point.

New mounts come that shim installed im fairly sure. The rear rubber shims and mounts hold up very well anyway.  Ive never seen one that has any real wear compared to new,  though i replace the mounts for piece of mind its all the front strut parts the usually fall to bits

[hunter 408]

Cheers Eagle. Yeah I did a bit more investigation and see that the top mount has the shim installed. 👍

I’m  really in two minds about how much to replace when swapping the shocks over. On one hand it makes sense to me to refresh as much as possible as well as investigate the height difference. 
On the other I wait and replace it all at once after I’ve swapped shocks over and (hopefully) discover new shock will help fix me height issue as well as price of mind. 
. 
I don’t want to put new static shocks in if it right away without knowing if it’s  going to help the height differential as well. If this is the case I’d rather go for something like a KW v2 so I can even out the height. 

I hope I’m explaining this clearly, still recovering from a concussion 🤕 and getting thoughts out clearly is a bit muddly 

[Eagle 1680]

Yeah swapping a bit of pain but suppose it gives you some idea. Doing both set of rear arms is a good idea when you get new parts judging from your other thread. You need to remove the upper control arm anyway to remove the strut (easiest way imo) 

[hunter 408]

Does anyone have experience with E39 and KW V2 coil overs?

[Eagle 1680]

Came across some old KW V1 for E39, not sure if any use to you. They use factory mounts etc which i must of thrown away and require new front inserts (Koni and KYB do them maybe others) 

[hunter 408]

Cheers mate. Will keep in mind. Organising a shock swap next week when I’ve got a bit of time so see how that goes and make a plan from there. While they are out I’ll assess how flogged they are. 
 

for comparison I took a fellow club member e39 530 with 2 or 3 year old m sport 2 shocks and springs for a drive Saturday. Was very taught but compliant, was well impressed. Hopping back in mine still felt reasonable but not as “fresh” that’s for sure. 

[hunter 408]

got rear guide links refrshed and shoks swapped this week. it was noted they are quite worn with one leaking. 

The car was aligned today, coombes measured height also and only ~3 mm diff side to side now on their alignment platform. big diff in feeling when driviing too.

With the most worn shock in the left rear i can now hear it wooshing all the time as it compresses and rebounds, the right (old left) is silent)

so, from here i will be saving for new MS2 shocks and springs and other bits for a full refresh later this year.

 

[Eagle 1680]

I used MS1 struts on my ACS Msport 2 springs no problem. I don't really get why you'd spend all that money on new MS2 shocks and springs? You can probably get Bilsteins or Koni's with springs for less cost and better performance.

[hunter 408]

Tbh bilsteins have a pretty patchy reputation from why I’ve been reading across the models with many reports of harsh performance. What model have you used, Jared?
 

koni yellows I’d be happy with as had these in my E46. Doing some searching tonight I see demon tweeks seems to be one of a small amount of places that have fronts and rears.  

Ultimately i’d rather spend the money knowing what I’m getting than rolling the dice. 

Edited May 25, 2021 by hunter
Updated info based on updated research

[Eagle 1680]

Used all common models ( B4-B8 ) with various lowering springs, mostly in older models. I did have B8's re-valved to match to H&R springs on my old E30 which improved damping over certain surfaces. I didn't think think they were too bad but many factors to consider.

In saying that i prefer Koni's especially if you using std springs. Down side is rebound adjustment in rear on E39 isnt that easy to do (if adjustment required after install)

Shox.com is where ive got my Koni in the past for a decent price.