Double pump brakes

There is an easy check for air in the systems .
If the pedal is hard, and near the top, do the "air test".
Set the emerg to move the shoes out to the drum, so they can't return by the springs.
Have the brake pedal pumped a coupla times and held down, remove the m/c cap and watch the fluid surface for fluid return.
Have the pedal released, - with the shoes pegged against the drums, and the calipers pads that merely "relax", - there should be barely any return, if there is a heavy return, or " fountain" the only thing that can cause that return is air that you compressed with the pedal.
Bleed whichever system has the return .
Brake fluid is excellent paint remover, flush with water immediately if any gets on your paint.
Cheers.