I was inspecting my 2000 WR400 today and found the rear brake reservoir empty and very dirty. It appears the plastic is deformed near the top alllowing the brake fluid to leak out just under the lid. I am wondering if this has happened to anyone else? Is the deformity due to the exhaust being so close to the plastic? It has been suggested that maybe there is a chemical reaction between the brake fluid and the plastic? I was also thinking maybe replacing the master cylinder with a 2003 that does not have a separate plastic reservoir. Any comments or thoughts would be helpful!