Ok, I did this a couple of years ago to my '89 780 (read all about it in the FAQ) and have a couple of updates in case anyone is interested. First of all, I used the same parts (bilstein B46-1662 shocks and IPD overload coils). The major differences in the parts were that rather than have a machine shop fab the lower mounts, I tried to do it myself. Also, the overload coils were for a WAGON, so spring spacers became unnecessary for proper ride height (YAY!). The major difference in installation procedure was that rather than try to wedge the spring out with the trailing arm in place, I chose to unbolt it instead. This was MUUUUUCH easier. However, the task would have been difficult if not impossible had I not had access to the auto shop on base, complete w/ air tools, press, cutoff wheel, grinder, lift, and hydraulic tranny stand.

The quick and dirty version follows, email me if you'd like more details:

THE SPRINGS:

Buy IPD 200 series WAGON overload coils. When they arrive, cut off the pigtail. I cut it off right where it started to resume normal circumfrence, it was exactly one turn. They are now ready to go.

THE SHOCKS:

Buy Bilstein B46-1662 shocks. I get them from Shox.com. With a set of bilstein struts for the front, the total was about $391. Not bad.... less than $100 a corner for bilsteins, and about the same price as a pair of nivomats. Here's the fork in the road. The lower mount must be either fabricated (by you or someone else... I tried it myself and despite careful measurements, access to the right tools, and the experience of having seen it done correctly before, I still jacked it up) or cannibalized from the old nivomat. I went with the fabricated route last time, and have gone with the cannibalization route this time. Why? Because I spent about 4 hours trying to make my own mounts, only to discover when I went to install them that I had drilled the holes slightly off and a bit too far out, and they were too long in general and therefore wouldn't fit. Rather than leave the car in the shop, I took the old Nivos and proceeded to press out the metal center of the bushing. Naturally, the rubber was destroyed, so I just saved the center metal portion. Now here's the trick- the Bilstein already has a metal sleeve just the right size OUTER diameter in the middle of its rubber bushing. The metal sleeve is VERY firmly fixed to the rubber bushing. Fortunately, the rubber bushing is NOT very firmly fixed to the rest of the shock, and therefore can be pressed out without totally destroying it. At this point, I was running short of time, so I cut the bushing down one of the seams and used liquid wrench and a screwdriver to separate the rubber bushing from the metal sleeve. I then pressed the bushing back into the shock and the center metal portion from the nivomat back into the bushing. Seems to work fine. Next time, I'll look for a comparable bushing ahead of time, so I don't have to worry about saving the one I extricate from the bilstein.

THE INSTALLATION:

Three bolts secure the nivomat- one up top and two through the bottom of the trailing arm. Remove them. Three bolts and a nut secure the mounting point of the trailing arm (towards the front of the car) to the frame. I chose to remove them, because the way I had the car jacked up didn't allow easy access to the one bolt which went through the trailing arm bushings and secured to the mounting point. Maybe it would have been easier, but I don't know. I'll give it a shot next time I do one of these. I had the car up on a lift when I did this, and used an adjustable hydraulic tranny stand to support the trailing arm as I undid the bolts & nut, then I lowered the tranny stand and the trailing arm to remove the old spring and drop in the new one. Here's the fun part. Jack the trailing arm back up and hope that the bolt holes line up and you can get a few in. I ended up getting one or two started, but the big nut in the center wouldn't go, so I jacked the stand up a bunch more to lift that corner of the car off of it's lift support (VERY CAREFULLY), then moved the lift support from the jack point to underneath the trailing arm itself. Then, I lowered the tranny stand. This way, rather than the tranny stand pushing up on the trailing arm, I had the weight of the whole car pushing down on it. This provided a bit more compression and allowed me to get all bolts and the nut started sufficiently that I could crank them down securely. Now put in the new shock and you're all done! I previously suggested removing the caliper so it wasn't in the way, and as it turns out, dropping the trailing arm makes removing the spring so easy that the caliper removal step can be eliminated.

That's it, email me with any questions you may have.

-Jon
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1LT Jonathan T. Belmont-- '91 Coupe 165K 'Gustaf'