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AntonLargiader AntonLargiader is offline
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Join Date: Apr 2007
Location: Charlottesville, VA
Posts: 471
One of the problems is that the seals are not compatible with the 'other' fluids. I think this is why BMW went to mineral oil on the R1200 clutches; it is not incompatible with gear oil.

This is what happens when DOT4 slave cylinder seals are exposed to mineral oil. Gear oil would be similar:

The rear surface of the input shaft (where the rear input seal rides) gets trashed when these seals go. I'll take pictures of a bad one at some point.

Basically, if you get a reservoir full of mud, you have a bad slave cylinder and you might need to replace the rear input seal. Fortunately that can be done without opening the tranny, but if the shaft surface is damaged it's very awkward to smooth that out in place.
Anton Largiader
Charlottesville, VA

Last edited by AntonLargiader; 10-03-2008 at 03:19 AM..
Old 10-03-2008, 03:16 AM
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