Following another thread.
There's a story that says, don't push the brake caliper piston back in without opening the bleed nipple, or this will cause the seals in the master cylinder to "flip" or get damaged when the fluid is forced back up to the master cylinder, instead of out if the bleed nipple.
I believe this to be a myth. Certainly on the omega.
I'm not talking about the rights and wrongs of how to bleed brakes. Opening the bleed nipple when pushing the pistons back all makes perfect sense, to clear the old fluid that cops the most heat around the pistons in the caliper.
But I've never had a problem pushing the pistons in so the fluid is forced back to the reservoir. Not any of my bikes, and not on any of my cars. 3 of which have been omegas that I would say that I owned as day to day cars. I've had two others that where not daily drivers.
Question is, have you?
Have you ever seen or witnessed flipped or damaged seals in a master cylinder? And if so was it on an omega.
I say, MYTH.