Posted by steve Kanavas on April 01, 1999 at 20:49:50:
In Reply to: Is it DOT3 or DOT5? posted by David Sherman on April 01, 1999 at 20:35:25:
DOT 3 and 4 is conventional fluid comprised of glycol and other ingredients.
DOT 5 is silicone. It's also used in race vehicles for the high temperature capabilities. The advantage for the mil vehicles is that it's not hygroscopic as is glycol. Works well for vehicles intended for long periods of non use as is often the case with mil vehicles.
Look in the master cylinder of your car or truck.
DOT 3 or 4 will turn dark brown with time. That's the water from the atmosphere that has mixed with the fluid. A good reason to change your 3 or 4 fluid every two years.
Although DOT 5 silicones take extreme temperatures and aren't hygroscopic, silicones are poor lubricants for metal. You often will encounter surprising wear in aluminum master cylinders.
3,4,5? any will do for our trucks with the iron master cylinders. But... Don't mix them.
Steve