Per The Hagen Aquaclear manual:
"Every three months the motor should be removed from the case and thoroughly cleaned. Remove motor by twisting it in the direction of the arrow on the motor. The motor should rotate 90o. Pull motor gently down to prevent damage to filter case or motor guide.
The impeller shaft is permanently installed. Pull impeller out of impeller well. Rinse impeller and impeller well of accumulated slime deposits. To prevent kinked seal ring wet motor seal ring before insertion into filter case."
