Owner's Problem Description
The owner reports that their 1999 Mitsubishi Diamante began shaking and wobbling, particularly noticeable at the rear. After taking it for an alignment, they discovered excessive inner tire wear on the rear tires, which were replaced twice within a year. A tire technician indicated that the issue might be related to faulty bushings in the rear suspension, making it impossible to align correctly. The estimated cost for the necessary repairs is around $1800, excluding labor.
Professional Technical Analysis
The 1999 Mitsubishi Diamante, equipped with a 3.5L V6 engine and an automatic transmission, has approximately 120,000 miles. The owner has reported intermittent shaking and wobbling, predominantly felt in the rear section of the vehicle. Upon inspection, it was discovered that the rear tires were worn down to the steel belts on the inner sides, suggesting a significant alignment issue or suspension component failure. The vehicle's alignment was performed, but the problem persisted, indicating that the rear suspension bushings might be compromised. Faulty bushings can lead to misalignment, causing uneven tire wear and instability. This vehicle's symptoms align with known issues related to the rear suspension on the Diamante, especially in models with high mileage. The diagnosis may include checking the bushing condition, examining the rear control arms, and ensuring the rear axle is not shifted. Safety is a concern, as continued driving with these symptoms could lead to loss of control. The current condition necessitates immediate attention to avoid further tire damage and ensure safe operation on the road.
Possible Causes
Most common causes (ordered by frequency):
- Rear Suspension Bushing Wear: The bushings in the rear suspension can degrade over time, leading to misalignment and excessive tire wear. This degradation can result from environmental factors and driving conditions, especially if the vehicle has been exposed to harsh conditions. When bushings wear, they allow greater movement in the suspension components, affecting alignment and stability. Replacement parts should be OEM or high-quality aftermarket equivalents, typically costing around $1800 for complete rear suspension bushing replacement, not including labor. - Observed uneven tire wear on inner edges, technician's report of bushing issues, difficulty aligning rear suspension.
- Rear Control Arm Issues: The control arms in the rear suspension may be bent or damaged, causing alignment issues. This can happen due to hitting potholes or curbs. Damaged control arms will lead to incorrect geometry in the suspension, resulting in excessive tire wear and instability. - Visual inspection shows bent control arms, alignment readings indicate severe deviations.
- Tire Quality and Installation Issues: Poor-quality tires or improper installation can lead to premature wear and handling issues. If the tires were not properly balanced or aligned during installation, this can contribute to shaking and wobbling. - Check for tire balance and alignment history, signs of uneven wear patterns.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - Initial Visual Inspection: Begin with a thorough visual inspection of the rear suspension components. Look for signs of wear or damage on bushings, control arms, and alignment settings. Check for uneven tire wear patterns which can indicate misalignment or suspension issues. Document any notable findings.
- STEP 2 - Suspension Component Testing: Test the suspension components for play or excessive movement. This can be done using a pry bar to check for any movement in the bushings and control arms. Replace any components that show significant wear or damage.
- STEP 3 - Alignment Measurement: Perform a four-wheel alignment check to assess the current alignment settings. This will provide a clear picture of any misalignment that needs correction. Use a professional alignment machine and follow manufacturer specifications for adjustment.
- STEP 4 - Tire Inspection: Check the rear tires for balance and wear. Ensure they are properly inflated and that there are no signs of defects such as bulges or uneven wear. This is crucial to ensure that tire issues do not exacerbate the suspension problems.
