Upper Rack was coming apart

The trick in replacing the roller wheels is to remove the plastic/rubber "stop" that is attached to the front of the stainles steel track. I used a pair of needle nose pliers to bend the small plastic extension on the "stop" so it would be released and then remove the "stop" from both tracks. Once that is done then simply slide out the rack assuming some of the wheels are still attached to the tracks and/or the wheels.

The next step is to install the new wheels onto the rack. Then, slide the rack/wheels onto the tracks. Then, snap the "stops" back onto the racks.

You're done!!