You are having problems bleeding the brakes on a 95 merc sable It' 4 wheel disc abs and you are using a one man brake bleeder pump but fluid not moving?
If it's the rear wheels you're trying to bleed there is a vehicle ride height sensor valve in the left rear above the control arm. Possibly stuck or the arm with the spring on it has come off. If its not working or in the right position it will limit flow or it can also keep the rear brakes applied and cause them to wear out prematurely. Also check that your brake hoses are not restricted and the bleeder screws are not plugged. If the brake hoses have steel clips around them to hold the hose to the strut they may have a buildup of corrosion between the steel bracket & the hose restricting flow. Gently open the steel part that wraps around the hose a little to see if it helps. Try to get someone to help you to push down the pedal while you open the bleeders might be another option.