Arthur S Newport , RI June 22, 2018 Appliance: Whirlpool Dishwasher WDF520PADB7 Whirlpool Dishwasher Wdf520padb7: End cap disconnect. How to replace Upper Dishrack Rail. This is a new appliance so track must be damaged. Ordered new track and problem solved. Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes