[Mg-t] Brake Fluids - DOT 5 / DOT 5.1 Mixtures (dont do it!) What happens?

[Mark J Bradakis]

The silicone fluid does not absorb water.  The traditional fluid does.
When both are used in the system the silicon is lighter and floats,
so to speak, while the traditional fluid tends to pool in the low
spots in the system.  Like in the calipers, where water vapor can
sneak in past the piston seals.  Over time this results in a blob
of waterlogged glycol fluid in the hottest point of the system.
It basically boils, turns into steam and steam is a LOT less
compressible than non-boiling brake fluid.

So the brakes quit working, and bad things happen.

mjb.