How To Remove and Replace Shock Absorbers

Dealing with worn or leaking shock absorbers is a common task for classic car enthusiasts. Whether you're aiming to refresh your suspension or replace units that have given up the ghost, understanding the removal and replacement process is crucial. This guide will walk you through the steps involved, drawing on practical experience to help you get your vehicle back on the road with a revitalised ride.

Understanding Your Shock Absorbers

Shock absorbers, or dampers, are vital components of your car's suspension system. Their primary role is to control the oscillation of the springs, preventing the vehicle from bouncing excessively. By dissipating the energy from road imperfections, they contribute significantly to ride comfort, handling, and tyre contact with the road surface. Over time, seals can degrade, leading to oil leaks and a loss of damping effectiveness, which can manifest as a bouncy ride, poor handling, and uneven tyre wear.

When to Consider Replacement or Service

Several signs indicate that your shock absorbers may need attention:

• Excessive Bouncing: If your car continues to bounce after hitting a bump, the shocks are likely failing.
• Leaking Fluid: Oil or hydraulic fluid on the exterior of the shock absorber is a clear sign of a seal failure.
• Uneven Tyre Wear: Worn shocks can cause tyres to skip and hop, leading to cupped or feathered wear patterns.
• Poor Handling: A noticeable decrease in steering response or an increase in body roll during cornering can point to worn shocks.
• Visible Damage: Cracks, dents, or bent components on the shock absorber housing should be addressed immediately.

The Removal Process: Step-by-Step

The exact procedure for removing shock absorbers can vary slightly depending on the vehicle make and model. However, the general principles remain the same. For many older vehicles, particularly those with independently sprung wheels, the process often involves disconnecting the shock absorber from the suspension linkage.

Step 1: Preparation and Safety

Before you begin, ensure your vehicle is safely supported. Use sturdy axle stands on a level surface. Never rely solely on a jack. Wear appropriate personal protective equipment, including safety glasses and gloves. Gather your tools, which may include:

• Wrench set (open-ended and socket)
• Ratcheting wrenches
• Tie rod end puller (or a suitable alternative)
• Screwdrivers
• Degreaser and brake cleaner
• Collection container for old oil
• New shock absorbers (if replacing)
• Shock absorber oil (if servicing)
• Loctite (optional, for reassembly)

Step 2: Accessing the Shock Absorber

Locate the rear shock absorbers. On many classic cars, they are mounted externally to the suspension components. You'll need to gain access to the mounting points. This might involve removing wheels or other suspension parts, depending on your vehicle's layout.

Step 3: Disconnecting the Link Assembly

For many Armstrong-type, lever-arm shock absorbers, a common first step is to disconnect the shock absorber link assembly. This often involves a tapered joint similar to a tie rod end. A dedicated tie rod end puller is the ideal tool for this job. If you don't have one, or if the standard tool doesn't fit, a custom-made puller can be fashioned, as demonstrated in the provided information, using readily available parts like pipe, washers, and bolts. The key is to apply force to separate the tapered shaft from its mating hole. A few sharp taps with a hammer on the surrounding component can often help break the taper free after the puller is in place. Be careful not to damage the threads on the bolt.

Step 4: Removing the Mounting Bolts

Once the link assembly is free, you'll need to address the bolts securing the shock absorber itself to the chassis or suspension. These typically consist of a bolt and a nut. Using an open-ended wrench on the nut at an angle, while employing a ratcheting end wrench on the bolt head, can make this process more efficient. Ensure you have the correct size wrenches to avoid rounding off the bolt heads or nuts. Sometimes, access can be tight, requiring patience and perhaps some manoeuvring of the suspension to get the best angle.

Step 5: Removing the Shock Absorber

With all mounting points disconnected, the shock absorber should now be free to be removed from the vehicle. Carefully manoeuvre it out, taking care not to snag it on any other components. It's a good idea to have a place ready to set it down safely.

Servicing Your Shock Absorbers (If Applicable)

If your shock absorbers are structurally sound but have leaked or lost their damping fluid, a service might be an option. This involves careful disassembly, cleaning, and refilling.

Step 1: Cleaning

Begin by thoroughly cleaning the exterior of the shock absorber with a degreaser to remove any dirt, grime, or oil residue. This will make subsequent steps easier and safer.

Step 2: Draining the Old Oil

Locate the lower brass plug. Carefully remove this plug, often using a screwdriver. Be prepared for a small amount of residual oil to drain out. You may need to remove a spring and other internal components along with the plug. Keep these parts organised, noting their order, as they will need to be reassembled correctly. A small washer might be present, so pay close attention to its placement. Clean these components and the area they were removed from, perhaps using a spray of brake cleaner.

Step 3: Accessing the Top

Remove the six screws securing the top cover of the shock absorber. It's advisable to clean these screws and their associated lock washers; soaking them in a rust remover like Evapo-Rust overnight can be effective.

Step 4: Emptying and Flushing

With the top cover removed, you can now drain any remaining oil. Work the shock absorber's mechanism slightly to help expel all the old fluid. It's crucial to dispose of this old oil responsibly, as it is a hazardous waste. Flush the inside of the shock absorber with a suitable solvent, such as mineral spirits, to clean out any contaminants. You might need to repeat this flushing process.

Step 5: Refilling with New Oil

Once thoroughly flushed and cleaned, the shock absorber is ready for refilling. Use the correct type and viscosity of shock absorber oil as specified for your vehicle. The Roadster Factory is cited as a source for specific shock oil. Add a small amount of the new oil to the lower plug hole before reinserting the internal components and the lower brass plug. Then, refill the shock absorber through the open top. It's best to keep the shock absorber level, possibly secured in a vice, during this process. Work the shock absorber gently to help eliminate air bubbles. You can leave the top brass fill plug out and allow the oil to seep out until the correct level is reached, which is often indicated by oil appearing at the fill hole or a designated overflow point.

Step 6: Reassembly of Top Cover

Clean and replace the top cover, ensuring the gasket is in good condition (replace if necessary). Reinstall the six screws and lock washers. For added security, especially if the original locking mechanisms (like nylocks) might be worn, consider using a drop of blue Loctite on the screw threads.

Replacing with New or Rebuilt Units

If servicing your original shocks isn't feasible or desirable, replacing them with new or professionally rebuilt units is a straightforward option. The process for installation is the reverse of removal.

Step 1: Installation Preparation

Ensure the new or rebuilt shock absorbers are clean and ready for installation. If they are new, they may come pre-filled or require filling according to the manufacturer's instructions.

Step 2: Positioning the Shock Absorber

Carefully position the new shock absorber into its mounting location on the vehicle. Align the mounting holes with those on the chassis or suspension components.

Step 3: Securing the Shock Absorber

Insert and tighten the mounting bolts. As mentioned during removal, using a combination of wrenches can be effective. Ensure that the bolts are tightened to the manufacturer's specified torque if available. If reusing original nuts, especially nylocks, consider using a thread-locking compound like Loctite Blue if you suspect the nylon insert is compromised.

Step 4: Reconnecting the Link Assembly

Reconnect the shock absorber link assembly. This usually involves aligning the tapered shaft with its corresponding hole and ensuring it seats correctly. Tighten the nut on the tie rod end or link bolt securely. Again, consult your vehicle's manual for specific torque values.

Step 5: Final Checks

Once the shocks are installed, give everything a final check. Ensure all bolts and nuts are tight, and that no components were left loose during the process. Reinstall any wheels or other parts that were removed for access.

Troubleshooting Common Issues

Leaks after service: If serviced shocks leak, it often indicates a problem with the seals, either during disassembly, reassembly, or due to age. In such cases, replacement is usually the best course of action. World Wide Auto is mentioned as a supplier of reputable rebuilt shocks.

Stiff operation: If the shock absorber feels excessively stiff, it might be due to incorrect oil viscosity, internal blockages, or damage.

Noise from suspension: While shock absorbers themselves are typically quiet, worn mounting bushings or loose connections can cause clunking or rattling noises.

Comparison of Options: Service vs. Replacement

Here's a brief comparison to help you decide:

Frequently Asked Questions

Q1: How often should shock absorbers be replaced?
There's no fixed mileage, but typically, shock absorbers should be inspected every 20,000 miles and considered for replacement around 50,000 to 100,000 miles, or when symptoms of wear appear.

Q2: Can I use any type of oil to refill shock absorbers?
No, it's crucial to use the specific type and viscosity of oil recommended for your shock absorbers or vehicle. Using the wrong oil can affect damping performance and potentially damage the unit.

Q3: Is it safe to drive with worn shock absorbers?
While not immediately dangerous in the same way as brake failure, worn shock absorbers compromise your vehicle's handling, braking distances, and stability, making it less safe to drive, especially in emergency situations.

Q4: How do I know if my shock absorbers are leaking?
Look for oily residue on the shock absorber body, especially around the seals. You may also notice a bouncy ride or hear noises from the suspension.

Q5: What is a "tie rod end puller" and why is it used?
A tie rod end puller is a tool designed to safely separate tapered shafts (like those found on tie rod ends and some shock absorber linkages) from their mating holes without causing damage. It works by applying pressure to force the tapered shaft out.

By following these steps, you can confidently tackle the task of removing, servicing, or replacing your vehicle's shock absorbers, ensuring a smoother, safer, and more enjoyable driving experience.