i dont know if it's been said yet or not, but i would take a step beyond bleeding them and actually flush the fluid out. brake fluid only lasts for so long and moisture eventually kills it. crack open all four bleeders and let them gravity bleed (means, dont pump the pedal, just let gravity do the work) and keep filling the master with new fluid until clean fluid leaves the bleeders. you'll be surprised at how dirty the old fluid is.