My XT disc brakes tend to stick sometimes, and I read how to clean the caliper pistons and lube them with Mineral brake fluid or Silicone Grease. I can't find brake fluid or Silicone grease but I did find some Permatex Ultra Disc Brake Caliper Lube at the local auto parts. Its a Synthetic Lubricant and it says it will not attack rubber and can be used on pistons and rubber sleves and seals. Has anyone tried this to lube XT caliper pistons? If so does it work?