A silicone polymer fluid useful as a brake fluid comprising a polymer or monomer having 0 to 100 mole percent of polymeric or monomeric units selected from R.sub.2 Si(OM).sub.2 units, ##STR1## AND R.sub.2 SiO units, 0 to 100 mole percent of polymeric and monomeric units selected from RSi(OM).sub.3 units, ##STR2## AND RSiO.sub.3/2 units, 0 to 10 mole percent of units selected from the class consisting of (MO).sub.3 SiO.sub.1/2 units, (MO).sub.2 SiO units, (MO)SiO.sub.3/2 units and SiO.sub.2 units and 0 to 5 mole percent of units selected from R.sub.3 SiO.sub.1/2 units wherein the viscosity of the polymer may vary from 2 to 400 centistokes at 25.degree. R is a monovalent hydrocarbon radical, M is selected from alkyl, alkoxy, alkylene, alkoxyalkyleneoxyalkylene and alkyl polyether substituent radicals, wherein the preferred substituent for M is 2-methoxy-2-ethoxy-ethylene or higher and R is preferably methyl.