MOT Suspension Checks: What You Need to Know

The annual MOT test is a vital part of ensuring your vehicle is roadworthy and safe. Many car owners wonder about the specifics of what is checked during this mandatory inspection. One area that often sparks questions is the vehicle's suspension system. So, to answer the burning question directly: yes, the MOT absolutely covers a suspension inspection. It's a critical component for safe driving, and any significant issues will result in a failed MOT.

Why is Suspension Inspection Crucial?

Your car's suspension system is far more than just a comfort feature. It's a complex network of components that work together to ensure your wheels remain in contact with the road surface, absorb shocks from uneven terrain, and provide stability and control. A properly functioning suspension is essential for:

• Handling and Stability: A healthy suspension system keeps your car stable during cornering, braking, and acceleration. Poor suspension can lead to unpredictable handling, making it difficult to steer and control the vehicle, especially at higher speeds or in adverse weather conditions.
• Braking Efficiency: When you brake, the weight of the car shifts forward. The suspension absorbs this shift, ensuring all four wheels maintain optimal contact with the road. If your suspension is worn, it can significantly reduce braking effectiveness, increasing stopping distances.
• Tyre Wear: Improperly aligned or worn suspension components can cause your tyres to wear unevenly and prematurely. This not only costs you money in replacement tyres but can also compromise grip and handling.
• Ride Comfort: While safety is paramount, the suspension also plays a significant role in absorbing bumps and vibrations, providing a smoother and more comfortable ride.

What Suspension Components Are Inspected During an MOT?

During an MOT test, a trained inspector will examine various parts of your suspension to identify any wear, damage, or defects that could compromise safety. The key components checked include:

Shock Absorbers

Shock absorbers, also known as dampers, are vital for controlling the bouncing motion of your vehicle's springs. During the MOT, the inspector will check for:

• Leaks: Any visible signs of fluid leaks from the shock absorber body are a fail item. Leaks indicate that the seals have failed, and the shock absorber will not be functioning effectively.
• Corrosion: Excessive corrosion on the shock absorber body or mounting points can weaken the structure and lead to failure.
• Damage: Any physical damage, such as bending or cracking, will also result in a fail.
• Functionality: While not always explicitly tested for "bounce," a visual inspection for leaks and damage, along with the general condition, gives an indication of their performance. In some cases, severe wear might be evident from the vehicle's behaviour.

Springs

The springs support the weight of your vehicle and absorb the initial impact from bumps. The MOT inspection will look for:

• Cracks: Any cracks in the coil springs are a serious safety concern and will lead to an MOT failure.
• Corrosion: Significant corrosion that weakens the spring material is also a fail. Surface rust is generally acceptable, but deep pitting or flaking metal is not.
• Breakages: If a spring has broken, it will clearly fail the test.
• Incorrectly Seated: Springs must be correctly seated within their mounts. If a spring has slipped out of position, it's a fail.

Suspension Arms and Linkages

These components connect the wheels to the vehicle's chassis and allow for suspension movement. The MOT checks for:

• Wear in Ball Joints: Ball joints allow for pivotal movement. Excessive play or wear in these joints is a dangerous defect and will cause the MOT to be failed. The inspector will typically try to move the wheel to detect this play.
• Wear in Bushings: Rubber or polyurethane bushings isolate vibrations and allow for controlled movement in suspension components like control arms. If these bushings are perished, cracked, split, or completely missing, it's a fail.
• Bent or Damaged Arms: Any bent, twisted, or damaged suspension arms can affect wheel alignment and stability, leading to an MOT failure.

Wheel Bearings

While technically part of the wheel assembly, wheel bearings are crucial for smooth wheel rotation and are closely related to the suspension's performance. The MOT inspection includes checking for:

• Excessive Play: The inspector will check for any noticeable looseness or play in the wheel bearings by trying to move the wheel from side to side.
• Noise: Although not always detectable during a static inspection, if a bearing is severely worn, it might emit a grinding or rumbling noise, which could be noted.

Steering and Drive Shaft Joints

Components related to steering and power transmission to the wheels also impact suspension behaviour and stability.

• CV Joints: Constant Velocity (CV) joints, especially those covered by protective gaiters (boots), are inspected. If the gaiters are split, perished, or leaking grease, it can lead to premature wear and failure of the CV joint, resulting in an MOT failure.
• Steering Rack and Linkages: While primarily a steering component, excessive wear or play in the steering rack or its associated linkages can affect how the suspension performs and how the vehicle handles.

Common Suspension Failures and What to Look For

Understanding common failure points can help you proactively maintain your vehicle. Here are some signs that your suspension might be developing issues that could lead to an MOT failure:

• Uneven Tyre Wear: As mentioned, this is a strong indicator of alignment issues stemming from worn suspension components.
• Pulling to One Side: If your car consistently pulls to one side when driving on a straight and level road, it could be due to misaligned suspension or uneven tyre pressure, but worn components are a prime suspect.
• Excessive Bouncing: After hitting a bump, if your car continues to bounce multiple times, your shock absorbers are likely worn out.
• Clunking or Knocking Noises: Unusual noises when going over bumps, turning, or braking can indicate worn ball joints, bushings, or shock absorber mounts.
• Spongy or Soft Brake Pedal: Worn suspension components can affect braking performance, leading to a less responsive brake pedal.
• Visible Leaks: Any oily residue around the shock absorbers or suspension arms is a clear sign of a problem.

Can I Check My Suspension Before the MOT?

While a professional inspection is thorough, you can perform some basic checks yourself to identify potential issues before your MOT is due:

1. The Bounce Test: Push down hard on each corner of your car and release quickly. The car should bounce back up once and settle. If it bounces more than once, the shock absorber on that corner is likely worn.
2. Visual Inspection: Look for any signs of leaks from shock absorbers, cracked or perished rubber bushings, damaged springs, or split CV gaiters.
3. Listen for Noises: Pay attention to any unusual sounds the car makes when driving, especially over bumps or when turning.
4. Check Tyre Condition: Examine your tyres for uneven wear patterns.

Table: Suspension Components and MOT Implications

Here's a quick summary of what the MOT looks for regarding key suspension parts:

Frequently Asked Questions (FAQs)

Q1: Will worn shock absorbers automatically fail the MOT?

A: Worn shock absorbers will fail the MOT if they are leaking fluid, are corroded to the point of weakness, or are damaged. Simply being 'worn' without these specific defects might not cause an immediate failure, but it significantly impacts safety and can lead to other issues that will fail.

Q2: Is a slightly cracked spring a fail?

A: Yes, any crack in a suspension spring is considered a dangerous defect and will result in an MOT failure. Springs are critical structural components.

Q3: What happens if my CV gaiter is split?

A: A split or perished CV gaiter is a fail item. The protective gaiter prevents dirt and moisture from entering the CV joint. Once it's split, the joint can quickly wear out, leading to noise and eventual failure, which is a safety hazard.

Q4: Does the MOT check suspension alignment?

A: The MOT test does not explicitly check wheel alignment. However, if alignment issues are so severe that they cause excessive tyre wear or affect steering, this could indirectly lead to an MOT failure (e.g., due to the tyre condition).

Q5: Can I drive my car if it fails the MOT for suspension issues?

A: You can usually drive your car to a pre-booked appointment for repair or to a pre-booked MOT retest. However, if the suspension issue is deemed a dangerous defect, the vehicle may be deemed unsafe to drive, and you could be liable for prosecution if stopped by the police. It's always best to get dangerous defects repaired immediately.

Conclusion

The MOT suspension inspection is a thorough check designed to ensure your vehicle handles, brakes, and remains stable on the road. Understanding the components checked and the common reasons for failure can help you maintain your car and pass its MOT with confidence. Regular visual checks and listening for unusual noises can help you catch potential problems early, saving you from unexpected failures and ensuring your safety on the road.

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