have the spa-rite dura glass pump with a Century centurion 1.5 hp motor. Took apart my pump to change the bearings and shaft seal. That went smooth, but when I got the impeller back on I only hand tightened. If I hold with a wrench in the back and tighten more, it doesn't spin very easy after that. So I put it on hand tightened with the new impeller screw on tight and the new diffuser doesn't' line up when trying to screw in the 5 screws. The part is c1-200pa. Exact same as the one I took off. The brass ring was completely gone on the one i had. I have no idea what to do next. could it be something with the impeller that isn't letting the diffuser go far enough "on" to line the holes up? Just can't see how the same part number wouldn't line up.