Best way is to use a CLEAN turkey baster to suck the fluid out of the reservoir, fill it with fresh fluid, then let each wheel gravity bleed until clear fluid comes out. Be VERY careful to not let any hint of petroleum product get in the fluid. Even a thin film of engine oil, power steering fluid, or transmission fluid in a funnel will cause problems. Same with all kinds of axle grease. Don't let the reservoir run dry, especially if you have anti-lock brakes because that will just create unnecessary headaches getting the air out.
To do it faster with a helper, have him press the brake pedal half way to the floor when you have a bleeder screw open. Close the bleeder screw, THEN tell him it's ok to let up on the pedal. Do this over until clear fluid comes out. Never press the pedal more than half way down. Doing so could rip the lip seals in the master cylinder by running them over the crud and corrosion in the lower halves of the bores where they don't normally travel.
The reason to change brake fluid periodically is to get the accumulated moisture out. Moisture lowers the fluid's boiling point which can lead to brake fade, and it reduces the chance for corrosion to take place.
Keep the master cylinder cover on at least loosely and keep containers of new fluid tightly covered because it loves to suck moisture out of the air.
Wednesday, December 8th, 2010 AT 2:52 AM