Turn off the electrical power to your Kenmore dishwasher from your kitchen circuit breaker.
Open the dishwasher door, then pull out the top and bottom racks all the way in order to remove them from the dishwasher.
Locate the long, black inner feed tube from the bottom center of the dishwasher.
Remove the two screws from the inner feed tube. Turn the rear feed cap clockwise and the entire inner water tube assembly will become loose.
Lift up the water tube assembly and spray arm out of the dishwasher, then pull out the inner feed tube from the assembly.
Insert a flathead screwdriver into the rubber valve at the end of the feed tube, then pry off the valve.
Insert a new rubber valve onto the end of the feed tube and run the feed tube back through the assembly.
Place the water tube assembly and spray arm back into the bottom center of the dishwasher.
Turn the rear feed cap counterclockwise to lock it into place, then reinsert the screws into the feed tube.
Place the racks back into the dishwasher and then close the door. Turn the electrical power back on from the circuit breaker.