Here's a general overview; specifics may vary slightly depending on your exact model and transmission type. This is NOT a complete, step-by-step guide, but a summary of the process:
1. Preparation:
* Safety First: Disconnect the negative battery terminal. Support the vehicle securely on jack stands. Never work under a vehicle supported only by a jack.
* Gather Tools: You'll need a socket set (including deep sockets), a U-joint press or a suitable alternative (vise and sockets, careful hammering), a hammer, a pry bar, penetrating oil (like PB Blaster), a torque wrench, and possibly a driveshaft support. A new U-joint kit specific to your Caprice is crucial.
* Identify the Driveshaft: Determine which driveshaft needs attention (front or rear). The rear driveshaft is usually the one requiring U-joint replacement.
2. Driveshaft Removal:
* Disconnect the Driveshaft: This usually involves unbolting the driveshaft from the differential (rear) or transmission (front). You may need to support the driveshaft to prevent it from falling.
* Remove the Driveshaft: Carefully lower the driveshaft and set it aside.
3. U-Joint Removal and Replacement:
* Separate the U-Joint: Use a U-joint press to separate the old U-joint from the driveshaft yokes. If you don't have a press, you can try carefully tapping the caps out with a hammer and punch (socket), but be extremely cautious to avoid damaging the yoke or the driveshaft. Penetrating oil will help loosen things up. This is the most delicate part of the job.
* Install the New U-Joint: Carefully press the new U-joint into the driveshaft yokes using the press. Again, if you are using an alternative method, proceed slowly and carefully. Ensure the new U-joint is seated correctly and firmly.
* Repeat: Repeat steps for each U-joint on the driveshaft.
4. Driveshaft Reinstallation:
* Reinstall the Driveshaft: Carefully align and bolt the driveshaft back to the differential/transmission.
* Torque Specifications: Use a torque wrench to tighten all bolts to the manufacturer's specified torque. These specifications can be found in your owner's manual or a repair manual.
5. Final Checks:
* Check for Binding: After reinstalling, check for any binding or unusual noises while rotating the driveshaft by hand.
* Road Test: Test drive the vehicle to ensure the repair was successful and there are no vibrations or unusual noises.
Important Considerations:
* Repair Manual: A factory service manual or a reputable repair manual for your specific 1991 Caprice Classic is highly recommended. It will provide detailed instructions, torque specifications, and diagrams.
* Professional Help: If you are uncomfortable with any of these steps, seek professional help. Improper repair can cause serious damage and safety hazards.
* Balance: After replacing U-joints, it's generally recommended to have the driveshaft balanced. An unbalanced driveshaft can cause vibrations.
This is a simplified overview. Always consult a repair manual for detailed instructions and safety precautions. Improperly replacing U-joints can be dangerous. If you're unsure about any step, it's best to seek professional help.
