Ashley A Anchorage , AK December 28, 2014 Appliance: Whirlpool 4 1/2 Qt. Stand Mixer Classic - Tilt K45SSWH-0 Whirlpool Mixer K45sswh-0: My kitchenaid was missing the back cover (received it like that for free!) and the thumb screw was broken. How to replace Cover. I simply replaced the back cover, it only took 1 screw. Then I replaced the thumb screw as well. It took less than 5 minutes. Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes