Rusting Suspension Mounts: A MOT Nightmare

It's a common concern for many car owners, particularly as vehicles age: the dreaded phrase uttered by the MOT inspector, “The bodywork within 30cm of a suspension mounting is showing signs of corrosion.” This seemingly innocuous comment can send a shiver down the spine, conjuring images of expensive repairs and failed inspections. But what exactly does this mean for your vehicle, and how should you go about addressing it? This article will delve into the world of suspension mount corrosion, explaining its implications, potential repair strategies, and offering some guidance on what to expect.

Understanding Suspension Mount Corrosion

Your car's suspension system is a complex network of components designed to absorb shocks, maintain tyre contact with the road, and ensure a comfortable and controlled ride. The suspension mounts are critical connection points where these suspension components, such as shock absorbers, control arms, and subframes, are securely attached to the car's chassis or body. Due to their vital role and often exposed location, these areas are susceptible to corrosion, especially in environments where de-icing salt is frequently used or where moisture can accumulate.

When an MOT tester notes corrosion within 30cm of a suspension mounting, they are assessing the structural integrity of the vehicle. The concern isn't just superficial rust; it's about whether the corrosion has weakened the metal to the point where it could compromise the safety of the suspension system. Even a seemingly minor rust patch can, over time, eat away at the metal, potentially leading to a component detaching or failing under stress. This is why the MOT test has specific criteria to identify and flag such issues.

The MOT Inspector's Assessment

The MOT inspector uses a combination of visual inspection and gentle probing to assess the condition of these areas. The “tippity-tappity” referred to in the initial query often involves a small, specialised hammer or probe to tap on the metal. This helps to identify areas where the metal has become brittle or perforated due to rust. A car that is “on the way to being rotten” indicates that the corrosion is present, but perhaps not yet severe enough to cause an immediate failure. However, it’s a clear warning sign that action is needed to prevent future problems.

The 30cm rule is a guideline to ensure that any potential weakness in the immediate vicinity of a critical mounting point is investigated. This is because corrosion can spread, and a small spot might be indicative of a larger underlying issue.

What Does This Mean for Your Car?

If your car has failed or received an advisory for suspension mount corrosion, it means that the areas around these critical points are not considered to be in a sufficiently sound condition. This doesn't automatically mean your car is unsafe to drive, but it does mean that the issue needs to be addressed. The severity of the corrosion will dictate the necessary repairs.

Possible Scenarios:

• Minor Surface Rust: In some cases, the corrosion might be superficial. This could involve surface rust that can be cleaned back and treated with rust inhibitors and protective coatings.
• Perforated Metal: If the rust has eaten through the metal, creating small holes, this is more serious. It may require welding to repair the affected areas.
• Severe Corrosion: Extensive corrosion might necessitate the replacement of entire structural sections, such as a subframe or a significant portion of the chassis. This is often the most expensive type of repair.

How to Get It Fixed

The first step is to get a thorough assessment from a qualified mechanic. They will be able to strip back any underseal or trim that might be hiding the extent of the corrosion and provide a detailed report on the condition of the suspension mounting points.

Once the extent of the damage is known, you can discuss repair options with your mechanic. The most common methods include:

Repair Methods:

• Cleaning and Treatment: For minor corrosion, the area can be thoroughly cleaned, removing all rust. Then, a rust converter or inhibitor can be applied, followed by a protective underseal or paint. This is often a cost-effective solution.
• Welding and Fabrication: If the metal is perforated, a skilled welder can cut out the corroded section and weld in new metal. This might involve fabricating custom patches if specific parts are no longer available. This is where the “hot metal glue” mentioned previously comes into play – a colloquial term for welding.
• Component Replacement: In cases where the corrosion is so severe that the structural integrity cannot be restored through welding, or if a complete component like a subframe is heavily corroded, replacement might be the only viable option. This can be costly, especially if the part is rare or difficult to source.

Cost Considerations

The cost of repairing suspension mount corrosion can vary dramatically depending on the severity of the rust and the chosen repair method. It’s essential to get multiple quotes from reputable garages.

As a rough guide:

Please note: These are approximate figures and can vary significantly based on your location, the specific vehicle, and the garage’s labour rates.

How Many Suspension Mounts Does a Car Have?

The number of suspension mounts varies greatly between different vehicle makes and models. However, a typical car will have numerous suspension mounting points, distributed across the front and rear suspension systems. These include:

• Shock Absorber Mounts: At the top and bottom of each shock absorber.
• Control Arm Mounts: Where control arms connect to the chassis or subframe.
• Subframe Mounts: If the car has a subframe, it will be mounted to the chassis at several points.
• Anti-roll Bar Mounts: Where the anti-roll bar is attached.
• Spring Mounts: Depending on the suspension design, springs may have their own mounting points.

A common car might have anywhere from 8 to 16 major suspension mounting points, each of which could be a potential area for corrosion to develop.

Is This Expected on a 10-Year-Old Car?

While a 10-year-old car will naturally show some signs of wear and tear, significant suspension mount corrosion is not necessarily *expected* but is certainly not uncommon. Factors such as the car's operating environment (e.g., living in a coastal area or a region with harsh winters), the quality of the original rustproofing, and how well the car has been maintained all play a role. A well-maintained car in a dry climate might show very little corrosion, while a car exposed to salt and moisture might develop more significant issues, even at a younger age. The Civic mentioned in the initial query, at 10 years old, might be considered relatively young for severe corrosion, suggesting it may have faced challenging environmental conditions or perhaps a less robust original rust protection.

Preventative Measures and Maintenance

The best approach to suspension mount corrosion is prevention. Regular maintenance can help identify and address minor issues before they become major problems.

Tips for Prevention:

• Regular Cleaning: Wash your car regularly, especially the undercarriage, to remove dirt, salt, and debris that can trap moisture and accelerate corrosion.
• Underseal Checks: Periodically inspect the underseal for any signs of damage or peeling. If the underseal is compromised, moisture can get trapped underneath, leading to rust.
• Professional Inspection: Have your suspension and undercarriage inspected by a mechanic during routine services. They can spot early signs of rust and advise on protective treatments.
• Waxoyl or Similar Treatments: Consider having the undercarriage treated with a protective coating like Waxoyl, especially if you live in a high-risk area. This can provide an excellent barrier against moisture and salt.

Frequently Asked Questions (FAQs)

Q1: Can I drive my car if it has a suspension mount corrosion advisory?

A1: Generally, yes, if it's an advisory. However, it's crucial to get it repaired as soon as possible. If it's a failure, you cannot legally drive the car until it's fixed.

Q2: Is it worth repairing significant suspension mount corrosion?

A2: This depends on the overall condition of the car and its market value. For older or less valuable cars, the cost of extensive welding or component replacement might exceed the car's worth. For newer or more valuable vehicles, repair is usually worthwhile.

Q3: Can I do the repairs myself?

A3: Minor surface rust treatment might be a DIY job for those with some mechanical aptitude. However, welding or component replacement requires professional skills, tools, and a controlled environment to ensure safety and effectiveness.

Q4: What are the risks of ignoring suspension mount corrosion?

A4: Ignoring it can lead to a catastrophic failure of suspension components, potentially causing an accident. It will also lead to MOT failure in subsequent years, and the repairs will likely become more extensive and expensive.

Conclusion

Encountering corrosion near suspension mounting points during an MOT can be concerning, but it's a manageable issue if addressed promptly. Understanding the implications, seeking professional advice, and opting for appropriate repairs are key to ensuring your vehicle remains safe, roadworthy, and compliant with regulations. Regular maintenance and preventative measures can also significantly extend the life of these critical areas, saving you from unexpected expenses and potential safety hazards down the line. Don't let rust be the downfall of your vehicle; tackle it head-on with informed action.