Chris, Big job getting the canister out. It's a press fit in the maincase. You remove the insides of the canister and take the top piece off through the top of the maincase. Then you can straighten the top of the canister from the bottom carefully. Over the years most of these canisters are pulled down at the top from overtightening the nut holding the cap. Lots of times when the filter was changed the gasket was not replaced and people just over tightened the nut. Good luck.