Pull the upper dish rack out of the dishwasher, as far as it will go.
Insert a flat-head screwdriver in front of the tab on the rear of the rack stop. Bend the tab toward the back of the dishwasher so it clears the underside of the slider, and then twist the rack stop to remove it. Repeat for the other rack stop.
Remove the upper rack from the dishwasher.
Bend the tab on the wheel support so that it passes the rack support, and then remove the wheel and wheel support.
Place the new wheel onto the wheel post, and then snap the tab onto the rack support.
Slide the rack wheels back into the slider, and then snap the rack stops back into place.
Push the rack fully into the dishwasher, and then close the dishwasher door.