It will involve a few parts. Changing them if you have never done it can be a little tricky. The manual will help a little. I see no middle balance wheel on that machine?? Try eBay for parts. I would call dealers in California first for parts after checking eBay since they are local. After that, call Bob Kovar at Toledo Sewing. You might try College Sewing in England as well. Even with generic parts, will not be cheap!
glenn