Before You Begin:
* Safety First: Disconnect the battery's negative terminal. Use jack stands to safely support the vehicle – never work under a vehicle supported only by a jack. Wear safety glasses and gloves.
* Gather Tools: You'll need a variety of tools, including jack stands, axle stands, socket wrenches (metric), torque wrench, penetrating oil, a wheel puller (possibly), a drain pan, and possibly a transmission jack. Consult a repair manual specific to your 1999 Ford Expedition for the precise tools and torque specifications.
* Repair Manual: Obtain a factory service manual or a reputable aftermarket repair manual for your specific vehicle. This will provide detailed instructions, diagrams, and torque specifications crucial for the job. Improper torque can lead to serious damage.
General Steps (Highly Simplified):
1. Prepare the Vehicle: Secure the vehicle on jack stands. Remove the rear wheels.
2. Disconnect Components:
* Brake Lines: Carefully disconnect the brake lines from the axle. You'll likely need a flare nut wrench and appropriate containers to catch brake fluid. Bleeding the brakes will be necessary after reassembly.
* ABS Sensors: Disconnect the ABS sensors if equipped.
* Shocks/Struts: Disconnect the shocks or struts from the axle and the vehicle's body.
* Drive Shaft(s): Disconnect the drive shaft(s) from the differential. This typically involves unbolting the yoke and potentially using a slide hammer to separate the slip yoke.
* Exhaust System: May need to be loosened or partially removed to gain access.
* Wiring Harness: Disconnect any electrical connectors attached to the axle assembly.
3. Remove the Axle:
* Unbolt the Axle Flanges: The axle housing is bolted to the differential. Locate and remove these bolts.
* Remove the Axle Assembly: Carefully lower the axle assembly. This may require using an axle stand to support its weight. You might encounter some resistance.
4. Reassembly: Reassembly is the reverse of the removal process. Pay meticulous attention to torque specifications. Ensure all components are properly seated and secured. Bleed the brake lines.
Important Considerations:
* Differential: The differential itself might need to be lowered or even removed depending on the specific design of your axle assembly. This adds significant complexity.
* Axle Seals: Replacing axle seals is often recommended when removing the axle, to prevent leaks.
* Fluid Changes: This is an ideal opportunity to change the differential fluid.
Again, this is a drastically simplified overview. Attempting this repair without proper knowledge and tools could lead to serious injury or significant vehicle damage. Consult a repair manual and seek professional help if you are not experienced with automotive repair. The complexity varies slightly depending on whether you have a solid rear axle or an independent rear suspension (IRS). Your 1999 Ford Expedition likely has a solid rear axle, making this job even more labor-intensive.
