Here's a general overview of the process. Again, this is not a substitute for a proper repair manual. Variations exist between model years.
Tools You'll Likely Need:
* Jack and jack stands: Essential for safety. Never work under a vehicle supported only by a jack.
* Wheel chocks: To prevent the van from rolling.
* Lug wrench: To remove the wheels.
* Socket set and wrenches: Various sizes will be needed.
* Impact wrench (optional but highly recommended): Makes removing axle nuts and other stubborn fasteners significantly easier.
* Bearing puller: Specifically designed for removing wheel bearings. This is crucial and often requires specialized pullers depending on the bearing design.
* Bearing race and seal installer: To install the new bearings and seals correctly without damaging them.
* Torque wrench: Absolutely essential for tightening components to the correct specifications. Incorrect torque can damage parts or lead to failure.
* Penetrating oil (PB Blaster, etc.): Helps loosen rusted or stuck bolts.
* Clean rags and shop towels: For cleaning and preventing contamination.
* Grease: The correct type of wheel bearing grease is crucial.
* Safety glasses and gloves:
General Steps (Consult your repair manual for specifics):
1. Safety First: Secure the vehicle on level ground using jack stands. Engage the parking brake and use wheel chocks.
2. Remove the Wheel and Brake Components: Remove the wheel, brake caliper (support it with wire or a bungee cord to avoid stressing the brake line), rotor, and any other components that obstruct access to the axle bearing.
3. Remove the Axle Nut (or Nuts): This is often very tight. Use an impact wrench if possible. You may need to hold the axle flange to prevent it from turning while removing the nut.
4. Remove the Axle Flange: This may require additional tools depending on the year and design. You might need to remove cotter pins and other fasteners.
5. Remove the Old Bearing(s): This is where the bearing puller is absolutely critical. Use the correct puller to avoid damaging the axle housing. The old bearing(s) and seals should be removed carefully and completely.
6. Clean the Axle Housing: Thoroughly clean the axle housing to remove any debris or old grease.
7. Install the New Bearing(s) and Seals: Use the bearing race and seal installer to press the new bearings and seals into place. This is very important to prevent damage and ensure correct seating.
8. Reassemble: Reinstall the axle flange, axle nut (or nuts), and other components in reverse order of removal. Tighten all fasteners to the correct torque specifications as outlined in your repair manual. Improper torque is a major cause of premature bearing failure.
9. Check Your Work: After reassembly, check for proper wheel rotation and bearing play. There should be minimal to no play in the bearings.
10. Reinstall the Brakes and Wheel: Reinstall the brake components and wheel, tightening the lug nuts to the correct torque.
Important Considerations:
* Replacing bearings in pairs: It's best practice to replace both bearings on the axle at the same time, even if only one seems bad.
* Proper lubrication: Use the correct type and amount of wheel bearing grease.
* Torque specifications: Adhere strictly to the torque specifications in your repair manual. This is critical for safety and component longevity.
* Professional help: If you're not comfortable performing this repair yourself, take your Astro van to a qualified mechanic. Improperly installed wheel bearings can be extremely dangerous.
This is a simplified overview. Refer to a repair manual specific to your vehicle's year and model for detailed instructions and diagrams. Safety should always be your top priority.
