Remove the bolts that hold the 'wet end' of the pump to the 'dry end'. If the impeller is held on with a screw, it is a 'left-hand' tighten which means it turns the opposite way of normal screws. Be careful not to damage the impeller. Any scoring on it will effect its performance and it will only be worth doing if everything goes back together cleanly and properly. Replace and lube all O-rings with silicone lube. Make sure all bolts are tightened and do them in an alternating fashion to ensure that you get a good seal.
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