Replacement Rear Shock For 90 Buick Reatta

Replacing the rear shocks on a 1990 Buick Reatta can significantly improve ride quality and handling. While it might seem daunting, this is a task a moderately experienced DIYer can tackle with the right tools and information. This article will guide you through the process, outlining the necessary steps, tools, and considerations for a successful shock replacement.

Understanding Your Reatta's Suspension

Before diving in, it's helpful to understand the Reatta's rear suspension. The 1990 Reatta typically uses an independent rear suspension (IRS) system. This means each wheel reacts independently to road imperfections, leading to a smoother ride compared to a solid axle setup. The shocks, also known as dampers, are a crucial component of this system. They control the oscillations (up-and-down movement) of the springs, preventing the car from bouncing excessively after hitting a bump. Worn shocks can result in a bouncy ride, reduced handling performance, and increased tire wear.

Identifying Worn Shocks

How do you know if your Reatta's rear shocks need replacing? Here are some telltale signs:

Excessive Bouncing: After hitting a bump, the rear of the car bounces several times before settling.
Poor Handling: The car feels unstable in corners or during sudden maneuvers.
Nose Diving During Braking: While this is more pronounced with front shocks, worn rear shocks can contribute.
Leaking Fluid: Oil leaking from the shock body is a clear indication of failure.
Uneven Tire Wear: Cupping or scalloping of the tires can be a sign of suspension problems, including worn shocks.

A simple bounce test can also help. Push down firmly on the rear of the car, near the bumper. Release and observe how many times the car bounces. More than two bounces suggest the shocks are likely worn.

Tools and Materials Required

Gathering the necessary tools and materials beforehand will streamline the replacement process. Here’s a list of what you’ll need:

New Rear Shocks: Purchase quality replacements specifically designed for the 1990 Buick Reatta. Check part numbers to ensure compatibility. Consider gas-charged shocks for improved performance.
Jack and Jack Stands: Essential for safely lifting and supporting the vehicle.
Wheel Chocks: To secure the front wheels and prevent the car from rolling.
Socket Set: Including sockets and wrenches in various sizes, particularly metric sizes common on the Reatta. A 13mm, 15mm, and 18mm are commonly needed.
Torque Wrench: Crucial for tightening fasteners to the correct specifications. Refer to your Reatta's service manual for torque values.
Penetrating Oil: To loosen any stubborn or rusted bolts.
PB Blaster or equivalent: A good penetrating oil is your best friend when dealing with older cars.
Safety Glasses: Protect your eyes from debris.
Gloves: To protect your hands.
Wheel Bearing Grease (Optional): For lubricating any bushings or components you might encounter.
Service Manual (Recommended): A service manual specific to the 1990 Buick Reatta will provide detailed instructions and torque specifications.

Step-by-Step Replacement Procedure

Follow these steps carefully to replace the rear shocks on your Reatta:

Safety First: Park the car on a level surface, engage the parking brake, and chock the front wheels.
Loosen Lug Nuts: Loosen the lug nuts on the rear wheels using a lug wrench. Don't remove them completely at this stage.
Raise the Vehicle: Position the jack under the designated jacking points on the rear of the car. Consult your service manual for the correct locations. Raise the vehicle until the rear wheels are off the ground.
Secure with Jack Stands: Place jack stands under the frame rails near the jacking points. Ensure the jack stands are securely positioned before lowering the vehicle onto them. Never work under a vehicle supported only by a jack.
Remove Wheels: Finish removing the lug nuts and take off the rear wheels. Store them safely out of the way.
Locate the Shocks: Identify the rear shocks. They are typically located near the rear wheels, attached to the lower control arm and the vehicle's chassis or frame.
Apply Penetrating Oil: Spray penetrating oil on the shock mounting bolts and nuts. Allow it to soak in for at least 15-20 minutes to loosen any corrosion.
Remove the Lower Mounting Bolt: Using the appropriate socket or wrench, remove the lower mounting bolt that secures the shock to the lower control arm. Be prepared for the shock to drop slightly once the bolt is removed.
Remove the Upper Mounting Bolt(s): Remove the upper mounting bolt(s) that attach the shock to the chassis or frame. The upper mounting may consist of a single bolt, two bolts, or a stem with a nut.
Remove the Old Shock: Carefully remove the old shock from the vehicle. Note the orientation of any bushings or washers so you can reinstall them correctly on the new shock.
Prepare the New Shock: If the new shock requires assembly, such as attaching bushings or washers, do so according to the manufacturer's instructions.
Install the New Shock: Align the new shock with the upper and lower mounting points. Insert the upper mounting bolt(s) and tighten them loosely.
Install the Lower Mounting Bolt: Insert the lower mounting bolt and tighten it loosely.
Torque the Fasteners: Using a torque wrench, tighten all the mounting bolts to the manufacturer's specified torque values. Refer to your Reatta's service manual for these values. It's crucial to torque the bolts correctly to prevent damage or loosening. Over-torquing can strip threads, while under-torquing can lead to the bolts coming loose.
Reinstall the Wheels: Mount the rear wheels and tighten the lug nuts by hand.
Lower the Vehicle: Raise the vehicle slightly with the jack, remove the jack stands, and carefully lower the vehicle to the ground.
Torque the Lug Nuts: Using a torque wrench, tighten the lug nuts to the specified torque value in a star pattern.
Test Drive: Take the car for a test drive and check for any unusual noises or handling issues. If everything seems normal, you've successfully replaced the rear shocks!

Important Considerations

Rust: Older vehicles, like the Reatta, are prone to rust. Be prepared for the possibility of encountering rusted bolts or other components. A penetrating oil and patience are your best allies. In severe cases, you may need to use a bolt extractor or even cut the bolts off.
Strut Mounts (if applicable): Some Reattas might have a coil-over-shock design, where the shock is integrated into a strut assembly. If this is the case, you may need to compress the spring to safely remove and replace the shock. This requires specialized tools and is best left to experienced mechanics.
Alignment: While replacing rear shocks typically doesn't require a wheel alignment, it's a good idea to have one performed if you notice any unusual tire wear or handling issues after the replacement.
Service Manual: Always consult your Reatta's service manual for specific instructions, torque specifications, and diagrams. This will help ensure you're performing the job correctly and safely.
Bushing Condition: While you're replacing the shocks, take a close look at the condition of the suspension bushings. If they're cracked, worn, or deteriorated, consider replacing them as well. Worn bushings can negatively impact handling and ride quality.

Troubleshooting

Here are some common issues you might encounter and how to address them:

Stripped Bolt Threads: If you strip the threads on a bolt, you may need to use a thread repair kit (e.g., Heli-Coil) or replace the affected component.
Stuck Bolts: If a bolt is seized, try applying more penetrating oil and using a breaker bar for extra leverage. You can also try heating the bolt with a propane torch to help break the corrosion.
Incorrect Parts: Double-check that you have the correct replacement shocks for your specific Reatta model. Compare the old and new shocks side-by-side to ensure they are the same size and configuration.

Replacing the rear shocks on your 1990 Buick Reatta is a worthwhile project that can significantly improve your car's ride and handling. By following these steps carefully and paying attention to safety, you can successfully complete the job and enjoy a smoother, more comfortable driving experience. Remember, when in doubt, consult a qualified mechanic.