Position the Poulan Pro riding lawnmower onto a flat surface. Pull in the parking brake to engage the parking brake and prevent any accidental movement during blade replacement.
Raise the mowing deck to its highest level, pulling up on the adjustment lever and gaining access to the blades. Loosen the hex bolt in the center of the blade with the wrench.
Unscrew the hex bolt the rest of the way with your fingers. Slide off the hex bolt, locking washer and flat washer. Pull the old blade off the mandrel housing and set it aside.
Slide the newly sharpened blades into position on the housing post. Make sure the trailing edge of the blades are positioned upward, toward the mowing deck.
Fit the flat washer, locking washer and hex bolt to the housing. Tighten down the hex nut to 30 to 35 ft. lbs. of torque.