I really like how Shimano brakes feel and I like the mineral oil but I keep having the same issues with them year after year. I had XTs last year with the servo wave levers and got a set of Saints this year and after a while, the lever goes to the grip after not using them for a few seconds. When I go to bleed them the fluid in the reservoir looks dirty. Has anyone else had this problem and found a resolution? Are the o-rings on the caliper pistons leaking or is it somewhere else? It drives me crazy...I'm thinking about trying Formulas next...