Tools You'll Need:
* Jack and jack stands: Safety first! Never work under a vehicle supported only by a jack.
* Lug wrench: To remove the wheel.
* Wheel chocks: To secure the vehicle.
* Socket set and wrenches: Various sizes will be needed, including metric and possibly SAE depending on your specific model.
* Hammer and punch: For removing components.
* Bearing packing tool or grease gun with the appropriate adapter: To pack the new bearings with grease.
* Torque wrench: Absolutely essential to avoid damaging the bearings and axles.
* Penetrating oil (PB Blaster or similar): To help loosen rusted or seized components.
* Clean rags: To wipe off grease and debris.
* New rear wheel bearings and seals: Buy quality replacements, preferably from a reputable parts supplier. Get the correct parts for your specific axle configuration.
* Optional but helpful: Bearing race installer and remover tools. These make the job much easier, but can be improvised with careful use of a hammer and sockets.
Procedure (General Steps – Refer to your repair manual for specifics):
1. Safety First: Park on a level surface, engage the parking brake, and chock the front wheels. Use jack stands to securely lift the rear of the vehicle.
2. Remove the Wheel: Remove the lug nuts and carefully remove the wheel.
3. Remove the Brake Drum or Rotor: This process varies depending on whether you have drum or disc brakes. For drum brakes, you'll need to remove the brake drum (sometimes requires separating the backing plate). For disc brakes, you'll remove the caliper assembly (secure it to prevent damage to the brake lines).
4. Remove the Axle Flange Nut: This is usually a large nut on the axle shaft. You might need to hold the axle shaft with a wrench or use a breaker bar to loosen it. This nut is likely very tight. Mark its position relative to the axle flange before removal to ensure correct reinstallation.
5. Remove the Axle Flange: After removing the nut, the flange may slide off. If it's stubborn, use a hammer and punch carefully.
6. Remove the Old Bearings and Seals: This is where specific tools and knowledge of your axle design are crucial. You'll likely need to remove the inner and outer races, and the seals. The races might be pressed in and require special tools for removal to avoid damage.
7. Clean and Inspect: Thoroughly clean the axle housing and hub assembly. Inspect the axle shaft for damage.
8. Pack the New Bearings with Grease: Use a bearing packing tool or grease gun to ensure the bearings are properly lubricated.
9. Install the New Bearings and Seals: Install the new bearings and seals, paying close attention to the correct orientation. Use the appropriate tools to avoid damaging the new components. This step often requires careful pressing of the bearings and races into place.
10. Reassemble: Reassemble everything in the reverse order of disassembly, ensuring everything is correctly aligned and tightened to the correct torque specifications (found in your repair manual). Pay particular attention to the axle flange nut.
11. Check for Proper Bearing Play: After reassembly, carefully check for proper bearing play. There should be minimal play, but the bearings shouldn't be tight.
12. Reinstall the Wheel and Brake Drum/Rotor: Tighten the lug nuts to the proper torque specification.
13. Lower the Vehicle: Carefully lower the vehicle and remove the jack stands.
14. Test Drive: Test drive the vehicle, paying attention to any unusual noises or vibrations from the rear wheel.
Important Notes:
* This is a simplified overview. Consult a repair manual specific to your 1996 GMC Jimmy 4x4 for detailed instructions, torque specifications, and diagrams. Incorrect procedures can lead to serious damage and injury.
* If you're not comfortable performing this repair yourself, take it to a qualified mechanic. Wheel bearings are critical safety components.
* Take pictures throughout the process to help with reassembly.
Remember, safety is paramount. If you're unsure about any step, seek professional help. This information is for guidance only and does not replace the need for a proper repair manual and mechanical expertise.
