Sliding patio door roller assembly

Hi I just moved into a house and the sliding patio doors for the sunroom don't slide anymore. I took the doors off and pulls out the roller assembly. I went to Home Depot and other places and nobody carries this assembly. I understand it is for old patio doors but something has to work. Please tell me you can help. Here are some pictures and measurements.
Wheel: 1 1/4 diameter 5/16 width
Pin: 1/4 inch diameter
Thanks