Here's a general outline. Specifics may vary slightly depending on which driveshaft (front or rear) you're working on and the exact Bronco model. Consult a repair manual specific to your 1990 Ford Bronco for detailed diagrams and torque specifications. These are crucial for a successful and safe repair.
Tools You'll Need:
* Jack and jack stands: Essential for safety.
* Wheel chocks: To secure the vehicle.
* Socket set: Including various sizes, likely metric.
* Wrench set: Open-ended and/or combination wrenches.
* Hammer: A ball-peen hammer is ideal.
* Punch or drift: For driving out the u-joint caps.
* U-joint press (recommended): Makes the job much easier and prevents damage. You *can* do it with a hammer and punch, but it's much riskier.
* Grease: For the new u-joint.
* New U-joint: Make sure you get the correct one for your driveshaft.
* Torque wrench: Crucial for tightening bolts to the correct specification.
* Penetrating oil (PB Blaster, etc.): To help loosen rusted bolts.
* Safety glasses: Protect your eyes.
* Gloves: Protect your hands.
Steps:
1. Preparation:
* Safety First: Secure the Bronco on jack stands. Engage the parking brake and use wheel chocks.
* Locate the U-Joint: Identify the driveshaft with the bad U-joint.
* Drain the differential: If working on a rear driveshaft, drain the differential fluid to avoid spillage.
2. Remove the Driveshaft:
* Disconnect the driveshaft: This usually involves removing bolts at the differential and the transmission (or transfer case). Consult your repair manual for specifics. You may need to support the driveshaft to prevent it from falling.
* Remove the driveshaft: Carefully lower the driveshaft to the ground.
3. U-Joint Removal:
* Support the driveshaft: Find a way to securely support the driveshaft while you work on the U-joint. A workbench vise may be helpful.
* Remove the straps/retaining clips: These usually hold the u-joint in place.
* Remove the u-joint caps: Use a punch and hammer (or a u-joint press) to carefully drive out the u-joint caps. Work on one cap at a time, applying even pressure. Penetrating oil may help loosen things up.
* Remove the old U-joint: Once the caps are removed, the old U-joint should slide out.
4. U-Joint Installation:
* Lubricate the new U-joint: Lightly grease the new U-joint's bearing caps.
* Install the new U-joint: Carefully press the new U-joint into place. A press is strongly recommended here to avoid damaging the new u-joint. If using a hammer and punch, be extremely careful to avoid damaging the u-joint.
* Install the retaining straps/clips: Securely install the retaining clips.
5. Reinstall the Driveshaft:
* Install the driveshaft: Carefully align the driveshaft and install it back onto the differential and transmission (or transfer case).
* Tighten the bolts: Tighten the bolts to the manufacturer's specified torque. Use a torque wrench to ensure proper tightness.
6. Reinstall and Check:
* Lower the vehicle: Carefully lower the vehicle from the jack stands.
* Check for leaks: Check for any leaks around the driveshaft connections.
* Fill the differential (if applicable): Refill the differential with the correct type and amount of fluid.
* Test drive: Test drive the vehicle to ensure everything is working correctly. Listen for any unusual noises.
Important Considerations:
* Repair Manual: A repair manual specific to your 1990 Ford Bronco is invaluable. It provides detailed diagrams, torque specifications, and other critical information.
* Safety: This job involves working under a vehicle. Always prioritize safety by using jack stands and wheel chocks.
* Proper Tools: Using the right tools will make the job much easier and reduce the risk of damaging parts.
* Torque Specifications: Follow the torque specifications in your repair manual precisely. Over-tightening can damage parts, and under-tightening can lead to loose connections.
If you are unsure about any step, consult a professional mechanic. This is a potentially complex repair and improperly done can lead to serious damage or injury.
