Here's a general overview of the process. Specific steps and tools may vary slightly depending on your exact axle configuration (e.g., 10-bolt, 12-bolt). Always consult a repair manual specific to your year and model K1500 for precise instructions and torque specifications.
Tools You'll Likely Need:
* Jack and jack stands: Safely lift and support the truck.
* Wheel chocks: Essential for safety.
* Lug wrench: Remove the wheels.
* Socket set and wrenches: Various sizes, including metric and standard.
* Impact wrench (recommended): Makes the job significantly easier.
* Drain pan: For axle fluid.
* New rear axle seal: Ensure you get the correct one for your axle.
* Seal installer tool: Helps prevent seal damage during installation. Improvised tools can be used, but a proper installer is preferable.
* Penetrating oil: Helps loosen bolts.
* Torque wrench: Absolutely crucial for proper tightening.
* Clean rags or shop towels: Keep things clean.
* Axle flange nut socket (usually large): May require a special socket.
* C-clamp (possibly): For compressing the seal during installation (depending on the seal installer used).
* Gear oil: Appropriate weight for your axle.
General Steps (Consult your repair manual for detailed diagrams and torque specs):
1. Safety First: Park on a level surface, engage the parking brake, and use wheel chocks.
2. Drain the Axle Fluid: Locate the drain plug on the differential housing and carefully drain the fluid into a drain pan.
3. Remove the Wheel and Brake Drum/Rotor: Remove the wheel and then either the brake drum (if drum brakes) or the rotor (if disc brakes). You may need to use a lug wrench and potentially a brake drum puller.
4. Remove the Axle Flange Nut: This nut is usually very tight. Use an impact wrench if possible. Mark its position relative to the axle flange before removal to ensure proper re-installation.
5. Remove the Axle Flange: Once the nut is off, the axle flange should slide off. However, it may be stubborn. A slide hammer may be necessary to remove it.
6. Remove the Old Seal: The old seal will likely be embedded in the housing. Use a seal puller or carefully pry it out, being careful not to damage the housing.
7. Clean the Housing: Thoroughly clean the axle housing bore where the new seal will go. Any debris will damage the new seal.
8. Install the New Seal: Use a seal installer to install the new seal correctly, avoiding damage.
9. Reinstall the Axle Flange: Make sure the axle flange is properly seated.
10. Reinstall the Axle Flange Nut: Tighten the nut to the proper torque specification (find this in your repair manual).
11. Reinstall the Brake Drum/Rotor and Wheel: Reassemble the brake components and wheel.
12. Refill the Axle with Gear Oil: Fill the differential with the correct type and amount of gear oil (consult your repair manual).
13. Check for Leaks: After driving a short distance, check for any leaks around the new seal.
Important Considerations:
* Bearing preload: Improper bearing preload can cause premature bearing failure. You may need specialized tools to set this correctly. If you're not comfortable with this, take it to a professional.
* Axle shaft damage: Inspect the axle shaft for any damage before reassembly.
* Torque specifications: Following the correct torque specifications is critical to prevent damage.
This is a simplified overview. Always refer to a factory service manual specific to your 1990 Chevy K1500 for detailed instructions, diagrams, and torque specifications. This information is for guidance only and should not be considered a substitute for professional advice. If you are not comfortable performing this repair, it is best to take your vehicle to a qualified mechanic.
