The info here got me thinking so I have been reading up on which grease we should be using when it comes to brakes.
Now the reason I use silicone and recommend it on the slid pins is because that is what the service manual (Haynes) says to use!.
RRG is not a good lubricant and should NOT be used on sliding pins, it can be used on the piston seals that is it.
Some say use brake fluid on the seals, my experience of this has never been good as the fluid absorbs water and turns into a white powder which causes the seals to stick to the pistons.
After spending an hour looking about the grease that should be used for the pins is this-
https://www.dowcorning.com/content/p...it/80-3507.pdf
It can be purchased here-
http://www.ebay.co.uk/itm/BRAKE-GREA...item3ad6096461
After reading up I have changed my mind about using silicone on the sliders!, a tube of the above grease will shortly be in my tool box.