Servotronic sleuthing

[6erWEBB]

So typically it seems my steering is being wonky, sometimes works at low speeds, sometimes not at all. Thing that makes it different than Im reading is the power assist will occasionally start working mid corner at 40, so the pressure youre putting on the wheel already becomes too much and ... makes things interesting.

So I pulled the servo to look into the screen.... which I didnt find. And the servo itself was held on with hex headed bolts not torx like Ive read it was. The servo itself however seems original with a date of 7/87

So, opinions? thing the symptoms point to the servo being old?

I also have a leak at the input shaft to diagnose which was dumping fluid onto the plug which isnt great. Anyways, ill report back with what I find.

[unity]

Did you look at the electronics end of it?

[6erWEBB]

Not yet but I did see there was something in the kick panel? that could cause some oddity... only reason I havent chased that yet is my symptoms didnt quite match those of the folks who chased the electrical part.. its on the list though.

[m735is]

Clean up the plug if the fluid in it and retest, that could fix it. If not I'm pretty sure there's newer versions that have a longer electrical pigtail so the fluid doesn't get in there- search on realoem, then search through a junk yard. Even if a junk yard has the same style, you can swap it and see if the converter is the problem. If that doesn't work, you can connect the plugs together in the kick panel and put it on full boost for trouble shooting purposes or leave it on full boost.

Shogun has tons of stuff on this subject.

[6erWEBB]

Yeah Ive been finding testing procedures slowly. I pulled the module from the kick panel and it looks clean (no burns) and it also has a 16/96 date on it so That may have been replaced. Ive got a steering box seal kit on the way, the plug was soaked in fluid so I think cleaning it may help. The thing that still bugs me is that there was no screen when I pulled the servo..

[shogun]

The screen must be there, unlesss it got lost missing in action before, pics on my website under servotronic. Unfortunately not available as single items, is part of the complete servotronic module. But easy to make one DIY. Pics
https://www.ecstuning.com/b-zf-parts...2411134770~zf/

[6erWEBB]

I swear it isn't in there. I did pull the module out and it looks good. I've got a couple things to try this week that may bring it back but I'd say a servo is in my future.

hey shogun, while you're in here, I traced a popping fuse 5 to the mustard relay and pulled it out to find... it's not "the mustard relay" but simply a yellow relay with 4large prints and one little one. Of course the parking lights wouldn't work but would that have popped the fuse?

[shogun]

Your 7/87 servotronic module is still the old square type module which has 1 in plug and one out plug, the 2 yellow ones. When you remove the 2 plugs from the servotronic module and plug them directly together (female and male plug), http://images3.bilder-speicher.de/sh...2500617988.jpg
the servotronic should always work on full power. If so, then the module is the problem and the repair is on my website. Some more pics when we repaired them years ago, we could even simulate speeds up to >250 kmh
http://infinitier.ddo.jp/e32/images/etc/p1100494.jpg
http://infinitier.ddo.jp/e32/images/etc/p1100496.jpg

This older type module is NLA and replaced by a relay type module, for that you would also need a new wire loom adapeter to match old/new. https://www.ecstuning.com/b-genuine-...t/32431162736/
32431162736 Servotronic Control Unit; Repair Kit for Servotronic Control Unit
Quite expensive though.
Some people have just made a DIY wire loom , details in here https://www.bimmerforums.com/forum/s...hydraulic-unit

as for the fuse and the relay, see here in the ETM which one it is, from around page 15 http://shark.armchair.mb.ca/~dave/BMW/e32/
or here pics http://bmwe32.masscom.net/johan/e_box/fuse_box.html

[6erWEBB]

Oh man! The relay with the updated pigtail is what I have! How bout that

[shogun]

Also that relay can go bad, test it. The good thing: if it is defective, it is cheaper and you already have the expensive updated pigtail.
Also a Audi Servotronic 7038 900 307 relay works. Someone on the German forum is using it on his E34 http://www.kawasuki.net/fotos/servotr.JPG
and here the BMW relay he replaced 7038-900 160 http://www.kawasuki.net/fotos/servo2.JPG
he used before the old BMW version with the round yellow plugs, therefore the adapter wiring.
Comment in German:
Da stehen bei der Relaisvariante auch die Klemmenbezeichnungen drauf, sprich 15, 31 etc... Bleiben noch 2 große Pins für das Ventil am LenkGetriebe ueber und ein kleiner Pin fuer das Geschwindigkeitssignal. Die Kennlinie gefaellt mir besser, weil ich das Gefuehl habe, dass beim runterbremsen die Lenkung auch schneller leichtgaengiger wird als voher. Mit dem altem Steuergeraet hatte ich immer das Gefuehl, dass man auf Parkplaetzen schon recht langsam fahren muss, bis das LenkGetriebe wieder leichtgaengiger wird. Es kann aber auch damit zusammenhaengen, dass das alte Steuergerät aus einem E34 M5 kommt. Ansonsten ist kein Unterschied zu spueren. Es ist genauso harmonisch wie vorher.

Translated: The characteristics I like more because I have the feeling that when I brake and speed goes down the steering changes faster to more power steering support as the old module from BMW. With the old control module I always had the feeling that one has to drive quite slowly on car parking lots until the steering gear switches to more power support again. But that can also be somehow related to the fact that the old control module for power steering was from an E34 M5. Otherwise, no difference is felt. It is as harmonious as before.