the rear brakes on our lumina are shot we just bought the car and discovered the pads are missing and the rotors are severely rusted and pitted i do not even know if the calipers work.can the rotors be turned or is it just as well to buy new.any advice would be helpful thanks.
1) The rotors can be turned if there is enough metal left on them to be safely used. There is a minimum thickness which varies depending on the manufacturer. If you bring it to a shop, most will replace the rotors, just for the extra bux.
2) I would compare the price to buying them new. The cost of new rotors vs turning them on our van was only a $5 difference so we bought new.
3) Remember that with ABS Brakes to block the line and crack the bleeder screws before you compress and that they turn while compressing. You can rent the tool from most auto parts stores inexpesively. Myself, I'd replace the calipers just because my son has a 93 Lumina and know that they freeze up due to mounting hardware issues. The Hardware kit is cheap and easy to install to ensure safety. We replaced the rotors for $30 each(Borg), calipers were $40 each(Wagner), pads were $25 for the Lifetime Pads(Wagner).
4) I wouldn't open the bleeder screws... I'd take the cap off the master cylinder and push the cylinders back with a clamp(front) or rears turn them back with a special tool its a cube with a bunch of different prong arrangements and you turn it with a 3/8 ratchet... About 11 at most parts stores.... That way when your done its not necessary to bleed the brakes
5) You GO RIGHT AHEAD. The 1st time you have to buy a NEW Accumulator you'll have learned 1 expensive lesson about ABS Systems. And THAT Folks is WHY We block the lines and bleed off thru the bleeder screw.