Brake problem after service

New to forum. 1995 safart AWD, ABS, after installing new shoes, wheel cylinders attempt to bleed. End up with no back brake pressure. Combination valve switch shows closed (0 ohms to ground). lots of pedal travel, at the bottom of pedal stroke front brakes are ingaged. Tried to reset the combo valve, no success. Any one have experience.

If the combination valve shows no resistance, it has shut off one of the hydraulic systems, in your case, probably the rears. Auto parts stores have a tool designed to force the valve to the center position for bleeding purposes. You can try to gravity bleed the rear brakes one at a time. When the fluid runs clear from the rear bleeders, close the bleeders, then push the brake pedal down, the valve should center itself. An alternative procedure to center the valve is to open a front bleeder and give the brake pedal a quick jab. That procedure doesn't always work, especially if there is excessive air in the rear hydraulic system.