This Tech Tips video will show you how to properly fix a sagging mortise lever
Step 1: Remove the inside lever from the door.
Step 2: Remove the outside lever to expose the spring cage.
Step 3: Locate the arrows on the spring cage and check their direction. The arrows should point in the direction the lever rotates down.
Step 4: If the spring cage is installed backwards, flip it so the arrows point in the correct direction for downward lever rotation.
Step 5: Reinstall the spring cage and the outside lever, ensuring it pops securely into place.
Step 6: Test the lever before reinstalling the inside lever to make sure it lifts up properly and locks the door.