I own a 2005 Hayward Northstar Pump. Diffuser went bad (cracked), bought identical replacement, all ready to go... and the motor won't go back into the pump housing. We are not able to flush motor mounting plate with pump flange. Hence we can't lock Motor Lock Ring. We tried pushing motor inside pump but no luck. I have checked diffuser, diffuser o-ring, seal plate o-ring, etc. Nothing else is blocking. I am 2 hours into just this part and hitting a wall. Any suggestion on how to fix this issue? Thanks in advance!