FinishLine Brake Fluid Mineral Oil 8oz. Finish Line's DOT Fluid exceeds the most stringent 5.1 specs and is completely compatible and mixable with all DOT 3, 4 or 5.1 spec'd systems. Finish Line's Mineral Oil Brake Fluid is far from your basic, common mineral oil - we spent some time in the lab and discovered, there's a big difference between your basic mineral oil and what we developed and are proudly calling 'high performance.