We are overseas at a leased home with one of these pentair? pumps with a nut and a bracket and nobody can figure out how to get it open. It must be an old style because I couldn't find a manual either:
Looks to me that you unscrew the knob and then slide the retainer tangs out of the way to remove the clear lid. Basket inside should then slide up and out. Do you have a photo of the actual pump showing the brand and model number? There should be a sticker or plate with this. I'm sure one of our pump experts will know about this specific pump.