Castrol, whose lubricating oil I always use, are taking a great interest in brake safety. They have issued reports of tests the Castrol laboratories have made on the behaviour of brake fluids. I now know that the hygroscopic factor in brake fluids, which troubled BMW recently, is concerned with the absorption of water into the fluid, which can reduce, from 240 deg. C., the temperatures at which it vaporises, leading to reduced braking efficiency or even total loss of braking. Castrol have introduced their Castrol Vapour Lock Indicator to warn of this, also a Castrol Brake Bleeder to enable those servicing brakes to bleed them single-handed and efficiently, and Castrol-Girling Universal Brake Fluid with advanced anti-vapour lock performance, and a safety-margin range of 17 deg. to 30 deg. C. – W.B.