Having almost 20 years experience with using silicon fluid on my C-300 and a few Type 1 VW products, some lessons learned can be identified. Compared to DOT 3 and 4 the silicon brakes do not seize up, especially disc brakes which otherwise frequently get stuck (VW discs which needed freeing up every 3 months of standstill with mineral, performed faultlessly for the next 10 years with silicon), there is less risk of rust in the cylinders as it is not hydroscopic and you will have less fading by hot brake fluid (higher boiling point). It does neither attack your paint. The downsides are sticking brake light switches (every 12 months on the VWs, also frequently on the C-300) rendering the switch either permanently on or off, it is actually compressible as John L has recognized (I once bottomed the pedal on one VW during panic braking, and there was no air in the system), and if you spill any it is really hard to later repaint the spot without silicon fish eyes. When introduced, the silicon fluid also gained a reputation for destroying old rubber gaskets/cups, so everything renewed is recommended. Blending silicon (DOT 5) with mineral fluid creates "porridge", so a total clean-out (spirit) is essential before changing back and forth. As I have recently learned, the engine runs very poorly (not at all) if you get DOT 5 into the intake. Bottom line: Unless you are racing, silicon brake fluid is beneficial for cars with external brake light switch as Tony Rinaldi recommends. For cars with pressurized brake switches, stick to mineral and change it every 2-3 years to avoid sticking and rust. Narve Nordanger (out to fix my C-300 brakes this week-end) [Non-text portions of this message have been removed] ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: mailto:Chrysler300-digest@xxxxxxxxxxxxxxx mailto:Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/