LAD regulating valve - disassembled - pics

[shogun]

http://www.bimmerboard.com/forums/posts/508927

[Jr ///M5]

Very interesting. I've got a few questions Eric, if you don't mind. Since there are only 2 valves that control the fluid flow, what type of wear was evident? Could the valves be turned or lapped to re-establish the seal? There appears to be some type of hydraulic ring seal used also, the bore inside the regulating valve where the seal rides looks worn, can this area also be re-polished and maybe a replacement seal used?

It would help to see the procedure used for dis-assembly, or does the ends just unscrew?

Thanks for posting the pictures, it sure looks simple enough.

Have you heard from the Polish guy with the key replacement rubber? If this works, I wouldn't mind buying a couple myself...

Thanks for your time,
JR

[shogun]

Replacement key rubber for E34/E32 key: the champs on the German E34 forum are working on it now after I gave them the hint from the German E38 7-Forum.
They are in direct contact with the guy in Poland. He said if enough demand, he can deliver end of May. First he will send 2 samples for testing to someone.
They are negotiating now a bulk order, already more than 100 sets are ordered now.

the LAD valve: (I did not do it by myself)
Here the original German text:
Symptom bei diesem Ventil war absolute Funktionslosigkeit.

Ursache war ein verkanteter Ventilstößel. Da beginnt auch gleich das Problem:
Der Stößel bewegt sich in einer Bohrung des Gehäuses und wenn diese Bohrung - was ich vermute - nicht mehr einwandfrei ist, blockiert das Ventil.
Vielleicht baut man es auch zusammen und es funktioniert dann wieder längere Zeit problemlos, wer weiß.

Defekte Dichtringe habe ich nicht feststellen können. Eine Besonderheit ist jedoch der Dichtring des Steuerkolbens: Dieser hat ein Quadratisches Profil und ist aus härterem Material. Dieser Ring dürfte für die meisten undichten Regelventile verantwortlich sein. Von außen ist nur eine Staubmanschette über die Kolbenachse geschoben.

Google translates that not good, so in short the meaning somehow, maybe someone can translate it better:

This valve was complete out of function.
Probably a stuck plunger of the valve.
The plunger moves in a bore of the housing, and if this - what I suspect - is no longer perfect, it blocks the valve.
Maybe also build-up of dirt.

Defective seals/gaskets could not be found.
A special design is, however, the sealing of the control piston ring: This is a Quad profile and is made of harder material. This ring is expected to be the problem for most leaking valves.

Lapping the valves should help.

[shogun]

The 2 valves have 2 different sizes, so you would need 2 different tools of these, do not know the exact English word for it
http://www.d-a.ch/html/share/shop/d/art/812/812546.htm

http://www.bimmerboard.com/forums/posts/509240

[Jr ///M5]

Thanks Erich, appreciate the information.

JR

[shogun]

Here are more pics of the disassembled regulating valve http://www.bryanborough.com/750iL/