Assuming the hoe runs off the tractor hydraulics, not a separate PTO pump, then the hoe hydraulics likely connect in series between the loader valve(power beyond) and the 3 point. The factory setup on the B2150, with a factory loader, is the 3 point gets its pressure from the power beyond port on the loader valve. That said, once you take off the hoe, you'd need to connect the two hydraulic ports(tractor side) together in order for the three point to get pressure. PLUS....on many subframe mounted hoe's, operating the 3 point with the hoe installed is a bad thing, so there may have been something done to disable the 3 point. OR....last but not least, there could genuinely be something wrong with the 3 point. Oh....reminds me, be sure to open the valve under the seat. It controls the speed of the 3 point, but I'm pretty sure if its turned all the way in one direction, the three point doesn't work at all. Hope at least something I've written helps.