Just to add to the furor.
I have a friend with a 58 Ford Ranchero. He has been running
silicone brake fluid in the beast for a long time. Guess what. He cannot
keep hydraulic brake switches in it. He has gone through just about all of
the American brands. It is the same thread as the MG one, so I tried an
Intermotor brand switch from our shelf. Same problem, again and again.
Four switches later I said enough! He now has a mechanical switch rigged
up. My own experience was that the switch on my race car was bad after
sitting for 10 years in a silicone fluid system. I installed a new switch
and so far it is still working. (I think).
What value am I adding to this discussion? Not much. In regular
use, the hydraulic switches seem to have a happy life, with good results.
Otherwise we would be having major complaints. With silicone fluid there
seems to be a lot of concerns, and for some reason evidence of a high
failure rate. Would I still run silicone? Yep.