Self Leveling Suspension/SLS Update

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Self Leveling Suspension/SLS Update

Post by Sbeaud »

So as noted in another post my self leveling suspension/sls was intermittently changing ride height erratically. I noted that the left shock was wet with fluid.
210915 BMW M6 Left Rear Shock - Wet.JPG
210915 BMW M6 Left Rear Shock - Wet.JPG (244.16 KiB) Viewed 1420 times
Pulled the spare tire and saw that the fluid level was just below the minimum mark. So I ordered new fluid (Pentosin CHF 11s), drained the system, blew out the lines and cleaned the reservoir.
210915 BMW M6 Self Leveling Suspension Pump - Clean.JPG
210915 BMW M6 Self Leveling Suspension Pump - Clean.JPG (121.15 KiB) Viewed 1420 times
Unfortunately when I was trying to remove the hose from the left shock the fittings were so tight I bent the tubing on the lower fitting, and rounded the upper fitting.
210915 BMW M6 Left Rear Shock - Damaged Hose - 1.JPG
210915 BMW M6 Left Rear Shock - Damaged Hose - 1.JPG (284.25 KiB) Viewed 1420 times
I checked a couple of local hydraulic shops to see if a replacement could be made, but no luck. But I did have a spare used hose from a complete system (non-M6) that I purchased from Rick Eickhoff. I refilled the system, but though the specs note a 1.5 liter capacity I put in 2 liters and still only came up to the minimum level. I believe the system is working correctly now as it does not change ride height while sitting stationary. But I've become hyper sensitive to ride height now and I could swear it seems to vary during driving.

1. Anybody have the entire hose created by a hydraulic shop? Tried a few local shops, but none did this level of custom work. At most some thought there would be a shop that could replace the hose portion - not the tubing/fittings. I've only checked a couple of shops, and in the Detroit area I have to believe there is a fair amount of custom work capability available - more work to be done. But if someone has a specific shop that has done a complete hose that may be easier than me traipsing around Detroit.

2. Thoughts on why so much fluid? I imagine a blown accumulator may fill up with fluid, but I thought accumulator failure created a very stiff (no-give) suspension. Mine seems to be damping reasonably well. But when draining a lot of fluid did come out of the left shock itself.

3. A number of references in the forum to Shogun from bimmerforums. Checked with him about any info on rebuilding E24 shocks. He was not aware of it being done, so he recommended replacing and doing a teardown of the "leaker". So I've ordered new left and right shocks and other pieces. Are there any other parts needed? I've ordered the items in the red boxes.
210915 BMW M6 Self Leveling Suspension Shock Diagram.JPG
210915 BMW M6 Self Leveling Suspension Shock Diagram.JPG (73.38 KiB) Viewed 1420 times
Last thought - I recognize that most folks delete the sls due to cost and the pursuit of lower ride height/improved cornering, but I'm keeping it.

Really appreciate any feedback!


Scott Beaudry
1988 M6
Posts: 26
Joined: Tue Dec 24, 2019 10:15 pm
Location: USA - South Carolina

Re: Self Leveling Suspension/SLS Update

Post by Ericjump »

I'm having a problem with my SLS also, I replaced the entire system (except the control box) with a system from a 635 when the guy removed the system for conventional shocks, and now it moves on its own, especially when I start the car. I've removed the control box opened it up, cleaned the contacts and can make the suspension go up and down by moving the arm but it usually stays full up. Anyone have a control box they want to get rid of? Has anyone herd of installing a toggle switch to adjust the ride height?
Thanks in advance for the help.
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