Pump not pumping

FarmWife 🌾 β€’ 2015 πŸ‘§πŸΌ 2017 πŸ‘ΌπŸΌπŸ‘ΌπŸΌ 2018 πŸ‘§πŸΌ 🌈 2020 πŸ‘ΆπŸΌ
One side of my pump barely sucks. I've cleaned the pieces and checked the membranes..?? What else can be wrong?