I've got a Hustler Super Z that just lost a drive motor. I had it rebuilt but the corresponding hydro pump is weak and it really drags compared to the other side. The wheel is also chattering when starting and it's obvious that the pump is putting a heavier load on the engine (to the point of bogging) than the other side. When I reinstalled the rebuilt motor I flushed everything, bled the system properly, washed out the reservoir, changed the drive belt, etc. After a test drive I parked it and checked for metal filings in the reservoir and sure enough, there were a few there. Tomorrow I'm taking the Hydro Gear BDP-21L pump apart to see what the problem is, but I'm sure it will cost as much to fix it as it would to buy a BDP-10A. I have found some good deals on the 10A's and could go ahead and replace both sides now for a little more than one 21L. I'm not in business so a loss in speed won't bother me, and I usually run slow anyway. My question is can this be done and if so, what are the drawbacks? I know the mounting flanges are a bit different but that should be a workable fix. Can I switch the pulley/fan to the 10A shaft or is it a different size? Maybe the whole idea is stupid, bit I'm ready to hear any input. Times are tough and I'm just trying to get some more life out of this beast while saving a few hundred bucks.