These pedals are great, but the gears in them are prone to breaking. Ours did too! So, here's a PETG, 3D printed replacement.
Our replacement fits perfectly and solves the issues of the pedal being useless without its gear!
It's a snug fit, so don't be afraid to use a little force to get it onto the d-shaft, and once it's on use the nuts to tighten it all the way down.
You'll need to slack of the bolt holding the treadle arm but that's obvious when you start.
5 mins and you're done!