This is from the slave I removed years ago and I recently found the exact same deposits in the clutch master cylinder when I replaced it. Light grey in colour, appears granular but when squeezed between fingers it is a smooth paste but, strangely enough, not greasy at all. If it is assembly lube there sure is a lot of it.

The slave is the factory original and the m/c which I replaced recently was a five year old Sachs I installed in 2012. I replace the fluid every couple of years, using the called for DOT 3. The old fluid always appears to be in pretty good condition without much discolouration.

Edited by George7941 (10/12/17 04:08 PM)
2006 GMC Sierra 4.3l, NV3500,G80 , Mobil 1 5W30, Dexcool.
1987 BMW R80 - sold
2015 Honda CBR300R

Staying out of the right lane a lot.