Rear brakes wont grab. on 1992 Nissan Pathfinder

Vehicle sometimes feels like it takes too long to stop, I put the rear wheels in the air, using a floor jack. Put the vehicle in drive, and spun the rear wheels, when I would depress the brake pedal the rear wheels would keep spinning,and the anti-lock light is on. Is this normal? already tried replacing both wheel cylinders for drum brakes, and shoes are also new. Can anyone help me with this issue? any suggestions?

Asked by for the 1992 Nissan Pathfinder
Anti lock light will be on because it expects the front wheels to be revolving at the same rate of speed as the rear (which are the driven wheels that you have jacked up in the air). Get someone to put their foot on the brake pedal with the truck on the ground and crack open the rear bleeder, if fluid reaches the rear the rear bleeders and comes out under force, the wheel cylinders are new and the brakes are properly adjusted the brakes "should" be operating. If the truck is jacked up in the rear when you open the bleed screw under pressure, fluid may be reduced or not flow out at all if the brake compensator is operating correctly (reduces fluid pressure to the rear as the truck's weight is transferred to the front under braking to maintain vehicle stability/control). If no fluid comes out when the wheels are on the ground brake pedal depressed I would look for a seized brake compensator valve and check the fluid line going to the rear at the master cylinder.
Drive the truck hard, use the brakes feel if the rear drums feel hot, if the brakes feel hot the rear brakes are working. On dry smooth ground see if you can lock up the rear tires.
I have put the truck up in the air using a hoist instead of floor jack after servicing rear brakes, I have bled rear brakes , indicating fluid is reaching rear cylinders. But once again, on a leveled rack, with all four wheels in the air, when brake pedal is depressed rear wheels don't stop, and thats with brake pedal to the floor, under extreme pressure. I am suspecting proportioning valve since vehicle is equipped with anti-lock, maybe valve is sticking? Causing only small amounts of fluid to reach rear wheels? How can I test proportioning valve? What do you recommend?