Just had my 3rd master cylinder failure in 2 years. The most recent one lasted about a week, purchased as "remanufactured" from NPD over a year ago as a back-up to keep on the shelf, aluminum housing, installed the Saturday before heading out to Sturgis Mustang Rally. Ran both sessions of the auto-cross driving school and the qualifier sessions - with the new rotors, calipers, and Hawk pads - the brakes worked AWESOME. Until the 2nd-to-last round of the finals on Sunday - suddenly, NO BRAKES, pedal goes right to the floor. Finished the run by coasting through turns and using the parking brake (still finished 14th). Upon inspection - no brake fluid leaks, again!
Rather than risking another Chinese rebuilt knock-off (which seems is all that’s available), I looked into getting this one rebuilt by a local remanufacturer / machine shop that does brake rebuilding for classic vehicles. Even though the bore is supposedly hard-anodized from OE, they recommended doing a stainless steel sleeve over basic rebuilding. Expensive solution ($190-$200) but they said since I no longer have the original MC, you can’t know what’s happened to the bore surface of the reman units after 30 years. Anyone here ever done this? Cost seems over-the-top but I am so sick of repeat MC failures that seem to happen at the worst possible times.