Drinking too much
beer in Munich ;)
Join Date: Feb 2012
Location: I would rather not say
If you can see the fluid level decrease significantly there may be a problem, such as a seized caliper which lets the pad skew under force but the pad pushes the cylinder back when the pressure is off. Perhaps one of the self adjusting mechanisms isn't working correctly ?
That said, I haven't looked at the fluid level of mine to see how far it moves but I really wouldn't expect to see much difference in level, the pads should be almost touching the disks anyway so onl a small amount of additional fluid needs to be used to clamp them onto the disk, and after that no more fluid is required as the pressure is increased by the servo (in most cases I've seen anyway)