DOT 5 fluid may not absorb moisture but this does not stop moisture from getting into a brake system. With the DOT 5, moisture will pool in the low areas and cause the corrosion there. Also, DOT 5 has a less than desirable expansion rate than the DOT 3, 4, and 5.1 fluids. It's common knowledge that DOT 5 is good for non-performance type cars, like vintage restorations and commercial trucks (the military uses this stuff in their trucks). I don't believe you will see DOT 5 used in any race car applications due to it's expansion rate. One good thing about DOT 5 brake fluid...it won't eat paint.