Originally Posted by Roadjunkie1
I have seen the Van's recommendation for the "O" rings with the lower temperature tolerance but have not seen the rational for that recommendation. Did I miss something? Curious minds want to know.
Original Cleveland are good to -65F
McMaster Carr Viton are good to -15F
Vans GLT Viton in U-00015 are good to -40F
I take off in winter at 15 to 20F often. Std temp lapse rate makes that approx -10F at 8,000ft. An hour there will have cold soaked the calipers and O-ring to -10F or -15F. I land and touch brakes and o-ring is cold and hard. Sure, once brake pads start touching you get a bunch of heat but maybe a bunch of fluid has already squirted past the hard o-ring.
YMMV if you never fly in cold weather.