Seals keep the lubricating agent (usually oil or grease) in the moving parts of your bike and the dust and grime out The worst thing that you can posibly do to a sealed component (such as bottom bracket, hub or suspension fork) is to use a powerfull hose to clean it, as this tends to force water through the seals, pushing out the lubrication and promoting corrosion
Devices used between rotating and stationary parts to separate, and minimized leakage between, areas of unequal pressures (060)
Caliper pistons are sealed in their bores by elastomeric rings seated in grooves The seals fulfill a secondary function of slightly retracting the pistons when line pressure reduced to zero at the end of braking This prevents "off brake pad drag", reducing both temperature and wear Both the compound and the mechanical design of these seals are critical The cross section of properly designed caliper seals is square, not round "O" rings cannot be substituted
Metal seals for the rotor tips and sides supercede piston rings Rubber seals are used to mate the peripheral and side housings
Fill or kill - A type of stock market or financial derivative order, signifying that the order is to be presented for execution, and if not executed ("filled") immediately—is to be cancelled