White Shepherd and Blue Devil stop-leak seems to have a strong following. They are the same product. I think that the White Shepherd name has been retired and replaced with Blue Devil. In any case, the active ingredient is diethylene glycol monoethyl ether, one of the chemicals found in the mixture of glycol ethers that comprise brake fluid. Does anyone have any experience with brake fluid as a stop leak? I'm not looking for "just replace the seal". I am asking for knowledge or a good guess about the use of brake fluid in oil as a stop leak.