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BMW – How To Eliminate Self-Leveling Rear Suspension (Shocks), E23, E24, E28, E32, E34, E31

June 5, 2013

Q
1991 M5
I have a suspension question. If I want to eliminate the self-leveling rear suspension and install a standard rear suspension what do I do with the hydraulic lines going to the shocks, where should I plug it? I’d like to remove the lines I don’t need.

A

BMW used a hydraulic self-leveling system on the rear suspension on various 5, 6, 7 and 8 series models from the mid ’80s through the mid ’90s.  There were two basic types of systems.  Both systems used rear shock absorbers that have separate hydraulic chambers that can be pumped and pressurized with fluid to raise the rear suspension and the vehicle ride height.  The ride height is monitored by a fluid regulator with a link connected to the rear swaybar.  Of the two systems, the earlier system  used a stand-alone electric pump and fluid reservoir to pressurize the rear shock hydraulic leveling chambers.  The later system used the vehicle’s power steering pump, reservoir and fluid to pressurize the rear shocks.

The early systems were used on the 82-88 E28 5-series (M5 only, in the US), E24 6-series through 89 (635csi, L6, M6 in US), E23 7-series through 87 (735i, L7 in US).

The later systems were used on the 89-96 E34 5-series (525it, 530it, M5 in US), 88-94 E32 7-series (735iL, 740iL, 750iL in US) and the E31 8-series (various 840i and 850i model variants).

When eliminating the rear self-leveling systems, you need to replace the shocks and the associated mounting hardware as well as the springs.  The self-leveling springs are typically shorter than the non self-leveling springs. Therefore, the springs must be replaced with standard non leveling springs.  Bavarian Autosport offers Self-Leveling Elimination Kits for all of these models.  The kits consist of all of the shock install parts that are different and need to be changed.  To perform a full elimination, you will need the Elimination Kit, 2 standard shocks (Bilstein, Koni, Sachs) and 2 standard springs.  We have all of these items in our online store at www.bavauto.com.

Click below for Self Leveling Elimination Kits:
(Click the link, then ID you BMW model and search “Self Leveling Elimination”)

With the early style systems, you can disconnect and remove all of the leveling system components, to include; shocks, accumulators, hydraulic lines, regulator, leveling sensor and link, pump and fluid reservoir (mounted under spare tire).

With the late style systems, you can remove the shocks, accumulators, hydraulic lines from the regulator to the accumulators and to the shocks.  With this system,
in performing the elimination, you can not just cap off the hydraulic pressure and return lines that come from the pump system. The pressure and return lines must be connected together after removing them from the regulator. Our self-leveling elimination kit addresses this.  Finally, you must keep the leveling warning sensor in-place (mounted on the passenger side trailing arm) to prevent a check-control warning from being displayed on the instrument cluster.

While the elimination kit does include a female-female union that can be used to connect the two hydraulic lines after they are disconnected from the regulator, this area is rather tight to work in.  We have found that we like to cut the two hydraulic lines where they come up from the driver side frame, into the area forward and above the driver side trailing arm (in the wheel well) and install nuts and flare the ends (bubble flare) then use two female/female unions and a short section of brake pipe (pre-flared with nuts) bent in a “U” to connect the two lines (with the unions between the male nut connections). You then just remove all of the original hydraulics from that point rearward.


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www.BAVauto.com
Bavarian Autosport

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