I was having some issues with my dishwasher, and did a pretty extensive cleaning and examination (I don't think this thing has ever been serviced or cleaned). Along the way, I pulled the pump/motor assembly and checked the seal, which was pretty worn. I have a new seal and installed it, but I can't seem to get the locking ring to lock the motor down enough to compress the seal. Is there a trick to getting the motor in tight enough?