If you mean the cylindrical bushing that slips into the round tubular seat base you cab find them in lots of places' Amazon will have them. Your needed diameter is 2 7/8 inches. The lip can be different so you need to match yours up to the options. Most marine stores will have them also.Here are some examples
exampl
If you are talking abut the slide bushings that fit between the moving part of a seat slider and the fixed flange on the underside of the slip, you will have a difficult if not impossible job to find a replacement. You may need to replace the whole seat slider mechanism or the seat and the slider
