I know there must be a trick to this. I am in the process of replacing the O-rings on my pool and spa pumps, both the small ones that go around the center of the impeller, and the larger (about 9") ones that seal the motor and impeller side to the strainer basket side.
I have swapped the O-rings, looks like they are the correct sizes put what do I need to do to squeeze the two sides together enough that I can start to tighten down the metal ring that goes around the outside? It seems like I need the gap to be less than about a 1/4 inch to seat the metal ring, but at the moment it is more like 3/4 inch. Does it help to remove the motor by removing the four bolts or am I just asking for more of a headache?