Timothy D Redding , CA December 11, 2021 Appliance: Maytag Washer MHWZ400TQ00 Maytag Washer Mhwz400tq00: Would not drain error code f21. How to replace Drive Belt. Replaced the water pump, also changed the drive belt as it was worn. Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes