Really? That sounds like a very easy fix, and you would probably wind up paying out the nose for someone else to do it. I'd start by giving the whole works a good cleaning. Scotch brite pads and fine grit sandpaper on the shaft to get rid of the accumulated gunk and grime. Get it as clean as you can and then give it a liberal application of something like WD-40, PB-blaster, or whatever you have on hand. There is usually a very close tolerance on those type of parts, so any little bit of gunk will make things hard. Once clean and lubed up, it should be easy. Maybe post a picture of what you are looking at so we can see what you are talking about and give better advice.
Also, do you have the set screw (and is there a key on the shaft)? If missing, those are cheap hardware store items.
Cheers,
Brad
PS: I'm unable to find a parts diagram for the model number you gave… are you sure that is correct?
Also, do you have the set screw (and is there a key on the shaft)? If missing, those are cheap hardware store items.
Cheers,
Brad
PS: I'm unable to find a parts diagram for the model number you gave… are you sure that is correct?