Doughie Posted November 4, 2002 Share Posted November 4, 2002 [slightly non-Supra off-topic, but interesting brake fluidy type stuff all the same] As part of the race prep for the Dubai 24hr kart race, one of our team members (who was a McLaren F1 mechanic for 17 years) brought along a litre of the full monty brake fluid that McLaren use in the F1 race cars. It had a nice label on it saying "Mobil 1" (for sponsorship reasons..) , and I said to our F1 mechanic "bet it's SRF". He didn't actually know if it was or not, so we peeled the Mobil 1 cover label off and sure enough, underneath it was ......... Castrol SRF !! So there you go - bog-standard SRF is used by McLaren for Kimi and David, so that's a pretty good endorsement for the stuff in my view. Anyway, when we got our kart for the 24 kart race, it had DOT 5 Silicone fluid already in it for it's Kelgate brakes. Bit of a shame as we were intending to bleed all the fluid off and use SRF instead, but I know that you can't mix glycol-based fluids like SRF with Silicone fluid DOT 5. Does anyone actually know why ?? Is it just that the 2 fluids simply won't mix at all ? Or is it that it will knacker the brake caliper piston seals ? Chris Wilson are you out there ? Our McLaren bloke reckoned that the SRF would have been fine as long as we flushed plenty of it through to get rid of the silicone fluid, and if it did knacker the seals, it only had to last 24 hours anyway. We never tried it though, but it would have been interesting to try it as it may have avoided some brake issues. In the end, we did have brake problems, including the pistons pushing the pads onto the disc of their own accord in the extreme 95degree heat of the day. The Kelgate brakes have self-adjusting calipers i think, and the silicone fluid either expanded slightly or something and we got pad/disk contact with foot totally off the brake pedal. Solution to this rather annoying problem is very simply that every time we came in to re-fuel / driver change, everyone simply pours litres and litres of water all over the brake assembly. - everything, disk, pads, caliper - the lot. It steams like hell, but makes the brakes feel like new for at least 5 laps or so.... ps. I have this unopened litre bottle of SRF now, so if anyone wants a litre of genuine ex-McLaren Castrol SRF then drop me a PM. Obviously for a few notes. pps. Kimi and David have signed the bottle, tripling it's market value. Quote Link to comment Share on other sites More sharing options...
Adam W Posted November 4, 2002 Share Posted November 4, 2002 How did you do in the race? At least you survived it! Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted November 4, 2002 Share Posted November 4, 2002 Some mixes seperate out, some, as I found once at Curborough when I assumed (stupidly) that a car i was testing had normal fluid in, form a jelly when mixed with normal fluid. Quote Link to comment Share on other sites More sharing options...
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