After changing the oil in my 318ti I was going to top off the fluids. The
brake fluid reservoir says only use DOT 4 brake fluid. The supply store
only has DOT 3.
Anybody know the difference or if DOT 3 can be used?
"grinder" wrote in
I had always thought you could put dot 4 into a dot 3 system but not the
other way around, however according to this:
'DOT 3 and DOT 4 fluids are mutually compatible, the major disadvantage of
such a mix being a lowered boiling point. In an emergency, it'll do.
Silicone fluid will not mix, but will float on top. From a lubricity
standpoint, neither fluids are outstanding, though silicones will exhibit a
more stable viscosity index in extreme temperatures, which is why the US
Army likes silicone fluids. Since few of us ride at temperatures very much
below freezing, let alone at 40 below zero, silicone's low temperature
advantage won't be apparent. Neither fluids will reduce stopping
Sorry about the earlier empty message - finger twitch.
That's not quite a crock. Dot 3 is Castor Oil - brake fluid has always
been an organic oil to *PREVENT* the rubber brake lines from breaking
down. You probably had aged lines or contamination.