Charles K Mechanicsville , VA May 23, 2022 Appliance: Whirlpool Dishwasher WDF520PADM7 Whirlpool Dishwasher Wdf520padm7: Top rack not cleaning dishes. How to replace Dishwasher Middle Spray Arm. The spray arm not spinning at all. Replaced spray arm. Worked perfectly. Part arrived in two days. Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes