Super Beetle brake maintenance

As I felt some strange feel at the state just before stop, inspected I front wheels of
 Super Beetle by lifting up, then unacceptable rotational resistance was observed in right side wheel, so to speak stuck feeling.
Following the natural countermeasure for this inconvenience, the brake drum was removed, no problem was found out in wheel bearings, inner and outer.
Careful checking on the operative cylinder, the sliding pusher for the trailing side was cohesively stuck. This kind of banish like material might have come from gradual leak of brake fluid or denaturing of silicon grease applied at assembling stage.
Removing all the banish there and reassembling the construction re-obtained the natural function again.
Whenever we start the brake maintenance work, some dust sheet under the wheel must be prepared, otherwise, the pit floor would be spoiled as shown in the picture.
I felt the necessity to check brake construction periodically, the maintenance sheet by the constructors is not prepared unreasonably.