1977-1985 Cadillac DeVille Rear Lateral Arm Replacement Guide
Eliminate rear-end wander and clunking noises by understanding and replacing your DeVille's lateral arm.
- A bad lateral arm on a 1977-1985 DeVille causes a dangerous rear-end wander and clunking noises.
- Aftermarket brands like Dorman are the most common and practical replacement option, as OEM parts are scarce.
- Replacement is a simple bolt-on procedure, but be prepared for rusted hardware on a car of this age.
- No specific recalls or TSBs exist for this part; failure is due to age and normal wear.
Is Your Classic DeVille's Rear End Feeling Loose?
The 1977-1985 Cadillac DeVille was built for a smooth, stable ride. After decades on the road, however, key suspension parts wear out. The rear lateral arm is a common wear item. Its bushings can dry out and crack, or the bar itself can be damaged, leading to noticeable handling problems. Because this part is essential for controlling the rear axle, a failure will make the car feel unstable and less safe to drive.
Symptoms of a Failing Lateral Arm
A bad lateral arm will make itself known through distinct sounds and handling issues. Here’s what to look out for:
- Clunking or Popping Noises: You may hear a distinct clunk or pop coming from the rear of the car, especially when going over bumps or turning. This is the sound of the loose bar moving and making contact with its mounting points.
- A Wandering or Loose Rear End: The most common symptom is a feeling that the rear of the car is swaying or shifting from side to side, separate from your steering inputs. This can make the car feel unstable, especially at highway speeds.
- Vibrations: In some cases, a very loose lateral arm can cause vibrations felt through the steering wheel or floor of the car.
- Uneven Rear Tire Wear: While less common for just a lateral arm failure, if the axle is allowed to shift consistently, it can contribute to unusual tire wear patterns.
How to Check Your Lateral Arm
You can perform a simple check at home. Have a helper rock the steering wheel back and forth just enough to shift the car's weight, but not enough to turn the wheels. While they do this, look at both ends of the lateral arm where it bolts to the frame and the axle. You should see no visible movement or play in the bushings or mounting bolts. Any clunking or visible movement means the bushings are worn and the arm needs replacement.
Choosing the Right Aftermarket Lateral Arm
For a vehicle of this age, original equipment (OEM) parts from GM are generally no longer available. The aftermarket is your primary source for a new lateral arm.
- Standard Replacement (Dorman): Dorman is a widely available aftermarket brand that produces a direct replacement lateral arm for the 1977-1985 DeVille. These parts are engineered to match the fit and dimensions of the original component, providing a reliable, stock-level repair. For most owners looking to restore the original ride and handling, this is the most practical and cost-effective choice.
A Note on Recalls and Service Bulletins
Searches of the National Highway Traffic Safety Administration (NHTSA) database did not find any recalls or technical service bulletins (TSBs) specifically related to the lateral arm for the 1977-1985 Cadillac DeVille. Any failure you experience is typically due to the age and normal wear of the part.
Replacement Cost
The cost to replace the lateral arm depends on whether you do the work yourself or take it to a professional mechanic.
| Item | Estimated Cost | Notes |
|---|---|---|
| New Aftermarket Lateral Arm | $59.63 | This is the typical price for a Dorman replacement part. |
| Shop Labor | $100 - $250 | Labor can take 1-2 hours. Costs vary by shop rate and how difficult it is to remove the old, potentially rusted bolts. |
| Total Estimated Cost | $160 - $310 | This is an estimate for professional installation. |
Frequently Asked Questions (FAQ)
Is it difficult to replace the lateral arm myself?
For a DIY mechanic with basic tools, this is a fairly straightforward job. The lateral arm is held on by two bolts. The biggest challenge will likely be breaking loose the old bolts, which may be rusted in place after 40+ years. Using penetrating oil and having a long breaker bar is recommended. Always use jack stands for safety.
Do I need a wheel alignment after replacing the lateral arm?
Typically, no. Replacing only the lateral arm on this type of solid rear axle suspension does not change the alignment angles like camber or toe. However, if you are replacing other suspension components at the same time, an alignment check is a good idea.
Should I replace the bolts when I replace the arm?
It is always a good practice to use new hardware, especially on suspension components. If the old bolts are heavily rusted or were difficult to remove, you should definitely replace them to ensure you can achieve the proper torque specification.
What is the difference between a lateral arm and a control arm?
On your DeVille's rear suspension, the control arms run parallel to the car and control the forward-and-back movement of the axle. The lateral arm (track bar) runs side-to-side and controls the sideways movement of the axle. Both are essential for a stable ride.
Technical Specifications
This is a non-adjustable steel bar with rubber bushings at each end, designed to control lateral movement of the solid rear axle.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.