One thing is for sure. No matter how well a hydraulic brake is, it WILL bleed through eventually. (That is why on cars the hand brake is mechanical and not hydraulic). Anybody who thinks they can set the hand brake and leave the plane that way will find when they come back that their brakes don't work, are mushy or will take a few pumps to get them to work again. The bled thru brake fluid has to be displaced up into the reservoir and drain back down again through a 1/4" tube by gravity to fill the cup. Use of the hand brake should only be temporary, until you chock the wheels or tie down, and then should be released.
