1. Locate the Spindle Assembly: The spindle assemblies are the components that hold the mower blades in place under the mower deck. They are usually connected to the deck with bolts or screws and have pulleys that engage with the drive belts.
2. Remove the Old Spindle Assembly: Use a socket set or wrenches to remove the bolts or screws that secure the old spindle assembly to the mower deck.
3. Install the New Spindle Assembly: Position the new spindle assembly in place on the mower deck and secure it with the bolts or screws you removed earlier.
4. Lubricate the Spindle Assembly (Optional): Before reattaching the mower blades, you can apply some grease to the spindle assembly to ensure smooth blade rotation.
5. Reattach the Mower Blades: With the new spindle assembly in place, reattach the mower blades to the spindle. Make sure the blades are installed in the correct orientation and securely fastened.
6. Reinstall the Mower Deck: Lift the mower deck back into position under the lawn mower and reattach any retaining pins or bolts that hold it in place.

how to replace lawn mower spindle assembly
how to change lawn mower spindle bearings