The problems occurred in two different cars and the braking systems were working perfectly apart from the fluid. I say the fluid boiled but obviously I didn't look in the reservoir to find it bubbling - but in a new system with no contaminants it had changed colour (slightly brownish). Some kind of denaturing had clearly taken place. The 300SL episode was on an MSA tour in a newly-rebuilt Healey. I had just gone up (a road-closed) Porlock Hill, not particularly fast (it was actually snowing!!), but it was the crawl back down that saw the brakes go. Pedal gradually going further down until nothing left, horrible feeling. Desperate pumping brought a bit back.Paul Blore wrote:If you managed to boil the silicon fluid Roger, you were either trying far too hard or something was amiss somewhere.
Anyhow, I use ATE Super Blue now, never had a problem apart from the colour it turns the reservoirs. For that reason I use BMW bremsflüssigkeit in the MCoupé as I don't want the plastic reservoir to turn blue.