SLS Removal, KONI vs Bilstein, etc (yes it's been done. so many times...)

[Warion7]

I just took my 1991 E32 out of storage and the SLS finally has given out completely for sides of the rear shocks. Rather than fiddle with repairing them per Shogun's writeup, I'm committed to removing the SLS entirely and putting a conventional suspension in them. Everything else so far is in great shape and it's continuing to be a great vehicle.

Here's the questions:

1. When I isolated the rear struts, I capped off the hydraulic feed outlet from the rear accumulator to the shock (accumulators are still holding and in place) as well as capped off the struts. The back end now rocks like Spinal Tap, which is why I want to remove the complex system. I capped off the accumulator feed to strut because there wasn't a return line, no issues have happened in the last week. If that's the case, do I need to remove the entire SLS system or just leave the accumulators and stuff there?

2. If I leave the accumulators, and SLS feed system, is there a reason to get the conversion kit to go from SLS to standard suspension? If so, has anyone put out a one for one replacement specifically to not require the conversion? Less parts = less time on a Saturday = less parts to fail.

3. I'm looking at Bilstein and Koni Shocks. Does one provide a marked difference over the other? Is there a third option I'm missing?

Thanks!

[shogun]

1. The easiest is you remove the outlet pipe towards the rear from the regulating valve and plug it, then the fluid still returns to the engine bay container. There must be a return so that the fluid is flowing, otherwise the power steering pump gets damaged.
Or just leave as you have it now.

2. no need

[Warion7]

"1. The easiest is you remove the outlet pipe towards the rear from the regulating valve and plug it, then the fluid still returns to the engine bay container. There must be a return so that the fluid is flowing, otherwise the power steering pump gets damaged. Or just leave as you have it now."

Thanks Shogun,

If I leave it as is, will it damage the power steering pump?

[Warion7]

And then last question:

735IL springs for vehicles with SLS removed are extremely hard to find, is there an issue going with 735I springs instead?

[shogun]

In case you leave as it, should be o.k., there is a max pressure valve and a min pressure valve inside the regulating valve. Disconnect the lever on the regulating valve and set the regulating valve to zero point, there is a hole in the lever and a small hole in the housing. http://twrite.org/shogunnew/systems/...#LAD_Regulator

735i springs are fine

[85k100rt]

When I removed SLS from my 750, I did so because I wanted to eliminate exposure to any issue with the hydraulic lines extending to the rear of the car which would render it undriveable. Road debris, an off road excursion, or simply old age of these lines could easily result in total failure of the hydraulic system at any time, rendering the brakes and steering assist useless due to uncontrollable fluid loss. I do a lot of cross country driving and absolutely didn't want to risk being stranded somewhere in the middle of nowhere, facing a large tow bill and the days long delay or expense associated in obtaining the necessary parts to repair the system. I resolved this potential by disconnecting the lines going to the rear and adding an additional hose from the high pressure pump outlet directly back into the return path to the hydraulic fluid reservoir. This was a cheap and extremely reliable fix. The addition of the non SLS 735 springs at the rear brought the car back to the correct ride height and correct alignment at the rear.

[shogun]

When I removed SLS from my 750, I did so because I wanted to eliminate exposure to any issue with the hydraulic lines extending to the rear of the car which would render it undriveable. Road debris, an off road excursion, or simply old age of these lines could easily result in total failure of the hydraulic system at any time, rendering the brakes and steering assist useless due to uncontrollable fluid loss. I do a lot of cross country driving and absolutely didn't want to risk being stranded somewhere in the middle of nowhere, facing a large tow bill and the days long delay or expense associated in obtaining the necessary parts to repair the system. I resolved this potential by disconnecting the lines going to the rear and adding an additional hose from the high pressure pump outlet directly back into the return path to the hydraulic fluid reservoir. This was a cheap and extremely reliable fix. The addition of the non SLS 735 springs at the rear brought the car back to the correct ride height and correct alignment at the rear.

That is the a good solution, eliminates all possible leaks in future. I still have my SLS and want to keep it, I recently had to replace the leaking feed line from the power steering pump going from front of engine around the lower oil pan and at the rear of the oil pan it is connected to a tube of the feed line towards the regulating valve. Only this leaking part cost me around $150 http://www.realoem.com/bmw/enUS/show...diagId=33_1553
Feed line 37131137458

Another possibility, also elegant and trouble reducing: the power steering pump for the E32 with SLS/LAD is a dual vane pump. If you remove the pistons and the springs from the pump for the SLS section, the section for SLS should not work anymore. See here a cross section drawing of the pump , item 1.4.2 Tandempumpe http://www.e38.org/e32/EDC%20german.pdf Have not tested it as I use the SLS, but some people on a German forum mentioned that.
the German text you can translate: Die Tandempumpe bestellt aus einer Fluegelzellenpumpe fuer die Servolenkung und einer Radialkolbenpumpe fuer die Niveauregulierung. Beide Pumpen sind in einem Gehaeuse zusammengefasst und warden vom Motor angetrieben, erzeugen jedoch zwei voneinander unabhaengige Oelstroeme.

Lenkung = steering
Niveauregulierung = SLS/LAD
Antrieb = drive


drawing 6 shows the regulating valve
1. Drehschieber = adjusting shaft
2. Hebel = lever
3. Ruecklauf = return line
4. Vorlauf = feed line
5. zum Verteiler = to flow divider
6. Druckablassschraube = bleed screw/pressure reduction screw
7. Absteckbohrung = zero point hole (this is where you insert a tool/bolt/ etc when setting the zero point)

[85k100rt]

Shogun, bypassing the hoses going to the rear as I described also is easily reversible if you ever want to return the car to its original state. Provided, of course, that you've kept all the necessary parts, which I did not.