Originally Posted by junebug1701
The PROPER procedure is to attach one end of a clear plastic hose to the bleed screw, and immerse the the other into a jar half-filled with new brake fluid. Then you loosen the bleed screw and compress the piston. The old fluid will go into the jar and no air can get sucked back in, only brake fluid. Close the bleed screw and move on to the other calipers.
James, that works just fine, but you still end up with several year old (and perhaps contaminated with dirt and moisture) brake fluid in the system after you replaced the pads. I like to flush the system and start with new fluid. Perhaps I am a bit obsessive about having clear and clean fluid, but brake new fluid is inexpensive and the process takes so little extra time.