Owner's Problem Description
The owner reports that their 1995 Ford Explorer's steering wheel shimmies and shakes when turning. They have checked the power steering fluid, which is full. Given these symptoms, they are concerned about a potential issue with the power steering pump, although they are unsure if it could be related to the steering column instead.
Professional Technical Analysis
The 1995 Ford Explorer is equipped with a 4.0L V6 engine and has an estimated mileage of around 150,000 miles. The reported symptoms of steering wheel shimmies during turns can be indicative of several potential issues. First, it’s important to evaluate the power steering system's fluid levels, which are confirmed to be adequate. However, if the steering wheel shakes, it could be attributed to air in the power steering system, especially after recent maintenance such as fuel pump replacement, which may have inadvertently introduced air into the system. Additionally, the power steering pump could be failing or experiencing cavitation, especially if it exhibits whining noises, which is common for failing pumps. The condition of the steering column and associated components should also be considered, as wear in these areas can lead to safety issues. Furthermore, the vehicle’s suspension and alignment should be examined, as improper alignment can exacerbate steering issues. Finally, thorough testing of the hydraulic pressure in the power steering lines should be performed to ensure there are no obstructions or excessive pressures that could affect steering performance. While the vehicle may have temporarily improved after driving it, continual monitoring is recommended to avoid potential safety risks.
Possible Causes
Most common causes (ordered by frequency):
- Power Steering Pump Failure: The power steering pump can fail internally, causing cavitation and inadequate fluid pressure, which leads to shimmies in the steering wheel during turns. The pump should be tested for proper pressure output (around 100-120 PSI) and checked for any abnormal noises. Replace with OEM part number F8TZ-3A674-B if necessary. - Whining noises from the pump during operation, loss of steering assist, evidence of air bubbles in fluid.
- Air in Power Steering System: Recent maintenance may introduce air into the power steering system, resulting in shimmies or shakes when turning. Bleeding the system may resolve this issue. Symptoms typically improve after driving the vehicle for a short distance. - Intermittent shaking that resolves after driving, presence of air bubbles when checking fluid.
- Steering Column Issues: A worn or damaged steering column can cause erratic steering behavior, leading to shimmies during turns. Inspection of the column and associated components is necessary to identify any wear or damage that may compromise safety. - Loose steering column components, visible wear or damage to the column or related parts.
- Suspension Alignment Issues: Misalignment of the suspension can lead to steering instability and shimmies when turning. A complete alignment check should be performed, and adjustments made as necessary to ensure proper vehicle handling. - Uneven tire wear patterns, difficulty in maintaining straight alignment during driving.
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 power steering system, including hoses, pump, and reservoir. Check for leaks or signs of wear. Use a pressure gauge to verify the pump output pressure.
- STEP 2 - Bleed the Power Steering System: If air is suspected, bleed the power steering system according to manufacturer specifications. Turn the steering wheel from lock to lock while maintaining fluid levels to allow air to escape. Monitor for improvements in steering feel.
- STEP 3 - Test Drive and Evaluate: Conduct a test drive while monitoring steering response to evaluate the effectiveness of the repairs. Pay attention to any remaining shimmies or unusual noises, and note any changes in steering feel.
- STEP 4 - Perform Alignment Check: If symptoms persist, check the alignment of the suspension components. Use a professional alignment tool to measure and adjust as necessary to restore proper handling characteristics.
