Michael S Vine Grove , KY January 02, 2015 Appliance: Whirlpool Undercounter Dishwasher WDF510PAYS2 Whirlpool Dishwasher Wdf510pays2 / : Lower dishwasher rinse arm. How to replace Dishwasher Lower Spray Arm. I ordered a new arm from appliancepartspros.com and replaced the arm. Appliance pros made it easy to find the right part by entering the appliance model number and viewing the schematic which gave me the part number for the part I needed. 2 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes