Porter Cable belt sander won’t track straight
I have a PC Whisper series 4×24 belt sander that I have used for a few years (just not very much). 2 days ago I used it sanding down a large piece of glued up mahogony. I wore out the belt and me. I used it today with a new belt and it wouldn’t track straight. I did allow the bag to fill and it may have stopped putting more dust in at the end of working before. There was a good bit of dust on the wood which I cleaned up tonight before I started. I emptied the bag tonight, cleaned up the sander, put on a new belt (50 grit) and now it won’t track. I tried all sorts of adjustments, multiple belts, including the former one, nothing tracks straight now. I have obviously done something to this tool. It was working perfectly well the last time I used it (2 days ago). I looked closely at the front wheel and it seems straight. The tracking adjustment works and moves the wheel. The back drive wheel looks ok, it seems symetric and round. There don’t seem to be any globs of crud anywhere. The dust collection is working quite well. There was something that was getting hot and smelling of hot plastic or rubber before, just at the end of my sanding for 30-45 minutes. But I haven’t found anything that looks like a problem. Does anybody have any ideas about how I can fix my sander? I really need to finish this board.
Thank you very much in advance,