HGV MOT Failures: Navigating Truck Suspension and Beyond

For any heavy goods vehicle (HGV) operator in the UK, the annual Ministry of Transport (MOT) test is a cornerstone of road safety and operational compliance. It’s a rigorous examination designed to ensure that lorries, buses, and trailers meet stringent safety and environmental standards. Following a temporary halt due to the Covid-19 pandemic, these vital tests have now recommenced, bringing renewed focus on vehicle readiness. While modern HGVs are engineered for durability and performance, wear and tear are inevitable, and overlooking seemingly minor issues can lead to significant problems, including MOT failure. Understanding the common pitfalls and how to proactively address them is paramount for maintaining vehicle uptime, ensuring driver safety, and avoiding the financial implications of retests and roadside prohibitions.

The Resumption of HGV MOT Testing: What You Need to Know

The Driver and Vehicle Standards Agency (DVSA) announced the resumption of HGV, bus, and trailer MOT tests from the 4th of July, marking the end of a three-month suspension. This period of grace, while welcome for many operators, means that a backlog of tests may now be due. It's more critical than ever to be fully prepared to ensure your vehicle is roadworthy and compliant.

Navigating Your HGV MOT Deadline Extension

While MOTs have resumed, the exact deadline for your HGV’s test will depend on its original due date. Vehicles that were originally due for their annual test in March or April 2020 have received a second three-month extension, pushing their new deadline to September 30th or October 31st, respectively. For those HGVs with an MOT originally due in May or June, the new deadlines are August 31st or September 30th. It’s crucial to verify your specific deadline to avoid operating an uncertified vehicle. If you are unsure about your vehicle's exact due date, the GOV.UK website provides a straightforward tool to check this information, ensuring you have ample time to prepare.

Preparing Your HGV for a Successful MOT

Preparation is key to a successful MOT. Beyond the obvious benefit of passing the test, thorough preparation is fundamentally about protecting your HGV drivers, other road users, and your business. The DVSA has consistently highlighted that many faults identified during MOTs should have been caught during routine driver walkaround checks. In fact, a 2019 DVSA article explicitly stated that "the majority of these faults could have potentially fatal consequences for the driver and other road users." This underscores the importance of daily diligence.

The Critical Role of Daily Checks

Driver walkaround checks are not merely a formality; they are a vigilant first line of defence against vehicle defects. Before an HGV even leaves the depot, drivers are mandated to perform a thorough inspection, covering everything from tyre condition and lamp functionality to fluid levels and brake integrity. This proactive approach allows for early detection of issues, enabling timely repairs before they escalate into serious safety hazards or MOT failure points. Embracing a culture of meticulous daily checks can significantly reduce the likelihood of unexpected breakdowns, costly repairs, and, most importantly, road accidents. It’s an investment in safety and operational efficiency.

Top 10 Reasons HGVs Fail Their MOTs: A Deep Dive

Based on DVSA data from recent years, we’ve compiled a list of the top 10 reasons HGVs fail their MOTs. This insight provides a valuable roadmap for operators and drivers to focus their preventative maintenance efforts, especially in the wake of extended test deadlines.

1. Lamps: Illuminating the Path to Failure

Lamps have emerged as the single most common cause of HGV MOT failures, surpassing headlamp beam aim in recent years. HGVs, by their sheer size and nature, are equipped with a multitude of lights: headlamps, fog lamps, brake lamps, side marker lamps, registration plate lamps, and more. Any of these lights being missing, incorrect in colour (e.g., white where amber is required), improperly positioned, or not securely fitted will result in an MOT failure. The good news is that these are often simple fixes. Regular checks of all lighting circuits, ensuring bulbs are working and lenses are clean and intact, can prevent this common pitfall. Pay particular attention to wiring and connections, which can become loose or corroded over time.

2. Headlamp Beam Aim: Dazzling Problems

While its failure rate has decreased slightly, headlamp beam aim remains a significant issue, accounting for 3% of HGV MOT failures. Misaligned headlights are not just an MOT concern; they are a major safety hazard, potentially dazzling oncoming motorists and reducing visibility for the HGV driver. The test requires headlights to shine within a specific band on a testing screen. Factors such as cargo loading, suspension condition, and even minor collisions can affect beam aim. Regular checks using a proper beam setter, or having a qualified technician adjust them, are essential. Drivers should also be aware of changes in their vehicle's headlight performance and report them promptly.

3. Brake System Components: Stopping Short of Compliance

Alarmingly, brake system components represent the third most common reason for truck MOT failures, accounting for 2.4% of failures last year. This category covers physical damage or defects to parts like brake discs, pads, drums, shoes, callipers, air lines, and hydraulic pipes. Damage can range from excessive wear and corrosion to leaks in air or hydraulic systems. Regular, professional brake inspections are vital, but drivers can also perform daily checks for visible signs of wear, leaks, or unusual noises during braking. Any sponginess in the pedal or reduced braking efficiency should be immediately investigated.

4. Service Brake Performance: The Power to Stop

Service brake performance issues contribute to 1.7% of HGV MOT failures. This goes beyond the physical components and assesses the actual effectiveness of the braking system under test conditions. It evaluates whether the vehicle can achieve the required braking force for its type of system (air pressure, vacuum, or hydraulic). Factors affecting performance include contaminated brake fluid (for hydraulic systems), air leaks in pneumatic systems, or malfunctioning ABS/EBS systems. Ensuring brake fluid is fresh and at the correct level, and that air systems are free from leaks, are simple checks that can make a big difference. Any reported issues with stopping distance or pulling to one side during braking must be addressed.

5. Steering Mechanism: Directing Trouble

Steering defects are extremely serious, directly impacting vehicle control and accounting for a notable percentage of failures. The MOT test checks for stiffness, excessive looseness (play), or roughness in the steering system. This includes components such as the steering box, linkages, power steering pump, and associated hoses. Loose bolts, worn ball joints, or damaged brackets are common culprits. Drivers should be highly attuned to any changes in steering feel, such as excessive play, difficulty turning the wheel, or unusual noises. Regular inspections for loose fasteners and worn components are crucial for preventing a steering mechanism failure.

6. Suspension: The Unseen Foundation of Your HGV

While accounting for 1.3% of HGV MOT failures, suspension issues are fundamental to vehicle stability, ride quality, and safety. The suspension system is designed to absorb road shocks, maintain tyre contact with the road, and support the vehicle’s weight. Modern HGVs typically employ either leaf spring suspension (common on older models and some trailers) or more advanced air suspension systems (prevalent on drive axles and modern trailers). Both systems are designed to be robust, but wear and tear are inevitable.

During an MOT, examiners meticulously check that the vehicle’s suspension is secure and correctly attached at all points. For leaf spring systems, this involves inspecting the springs themselves for cracks or fractures, and ensuring spring pins and shackles are in good condition and free from excessive wear or play. Worn bushes in leaf spring mounts are a common fault that can lead to imprecise handling and accelerated tyre wear.

Air suspension systems are checked for leaks in air bags (also known as air springs or bellows), damaged levelling valves, and compromised air lines. A leaking air bag can cause the vehicle to sag, affecting stability and potentially leading to uneven tyre wear or even tyre blowouts. Shock absorbers, which dampen suspension movement, are also inspected for leaks or damage; a failed shock absorber can lead to excessive bouncing and reduced control.

A visual check by the driver or technician is often sufficient to identify many suspension defects. Look for:

• Visible cracks or fractures in leaf springs.
• Worn or perished rubber bushes in spring eyes and shackles.
• Signs of air leaks around air bags or air lines (a hissing sound or a vehicle noticeably leaning when parked).
• Leaking or damaged shock absorbers.
• Corrosion or damage to suspension mounting points.
• Uneven tyre wear, which can often be a symptom of underlying suspension issues.

Addressing suspension issues promptly is vital not only for passing the MOT but also for ensuring the vehicle’s safe handling, load stability, and the comfort and safety of the driver. Neglecting suspension faults can lead to more severe component failures, increased tyre wear, and potentially dangerous driving conditions.

7. Exhaust Emissions: Clearing the Air

Exhaust emissions have climbed into the top 10, now ranking seventh. With government targets to significantly reduce emissions, this area is under increasing scrutiny. While some emission issues can be subtle, obvious signs like visible smoke (black, blue, or white) from the exhaust pipe are an instant failure. The MOT test checks for excessive levels of pollutants. Preventative measures include regular engine servicing, ensuring the fuel system is clean, and checking for exhaust system leaks. A properly maintained engine is more likely to meet emission standards.

8. Mechanical or Electric Parking Brake Performance: Holding Power

Parking brake performance issues accounted for 0.8% of test failures. The parking brake must have a secure mechanism and function fully and correctly when applied. For electrical parking brakes, they must not be damaged, inoperative, or malfunctioning. This is a straightforward check that can easily be performed before an MOT. Ensure the brake engages firmly and holds the vehicle securely, and that any associated warning lights are not illuminated.

9. Tyre Condition: Gripping with Confidence

Despite being a mandatory daily check, tyre condition still accounts for 0.8% of failures. Tyres are the vehicle’s only contact with the road, making their condition paramount for safety. An HGV will fail its MOT if a tyre has exposed ply or cord, is incorrectly seated on its wheel, is excessively worn (below the legal tread depth), or has any lumps, bulges, or tears. Regular daily inspections for cuts, punctures, adequate tread depth, and correct inflation pressure are essential. Pay attention to both inner and outer tyre walls, which can be easily overlooked.

10. Speedometer and Tachograph: Keeping Track

Speedometer and tachograph faults were responsible for 0.7% of MOT failures. HGVs must have a tachograph fitted unless exempt, and all seals and fixtures undergo a visual inspection. Failure points include a damaged tachograph, one not keeping accurate time, displaying miles per hour (mph) instead of kilometres per hour (kph) if required, or being entirely absent. These are easily verifiable items during daily checks. Ensure the speedometer is functioning correctly and that the tachograph is sealed, calibrated, and displaying the correct units.

Common HGV MOT Failure Statistics

To provide a clearer picture of where HGVs most commonly fall short during their MOT, here's a comparative overview of some of the top failure categories:

Frequently Asked Questions (FAQs)

• When is my HGV MOT due if it was postponed?
  Your new deadline depends on your original MOT due date. Vehicles due in March or April 2020 received a second 3-month extension (now due by Sept 30th or Oct 31st). Those due in May or June 2020 must be tested by August 31st or September 30th respectively. Always check the GOV.UK website for your specific vehicle.
• How can I best prepare my HGV for its MOT?
  The most effective preparation involves diligent daily driver walkaround checks and addressing any identified issues immediately. Focus on the common failure points like lights, brakes, tyres, and steering. Regular preventative maintenance by qualified technicians is also crucial.
• Are HGV suspension systems inherently bad?
  No, modern HGV suspension systems are designed to be extremely robust and reliable. However, like any mechanical system, they are subject to wear and tear over time. Issues arise from neglected maintenance, heavy loads, and poor road conditions, leading to failures if not properly maintained. The 1.3% failure rate indicates that while not a primary cause, it's an area requiring diligent inspection.
• What are the most common HGV MOT failures?
  Currently, lamps (lights) are the most common reason for HGV MOT failures, followed closely by headlamp beam aim and brake system components.
• What happens if my HGV fails its MOT?
  If your HGV fails its MOT, you will receive a refusal of test certificate. You cannot use the vehicle on the road until the defects are rectified and it passes a retest. Operating a vehicle with a failed MOT can lead to fines and penalties.

Ensuring Compliance and Safety: Alltruck plc's Commitment

At Alltruck plc, we understand the pressures HGV operators face, especially with the recommencement of MOT testing. We are committed to providing top-tier inspection services to help you achieve full compliance and maintain the highest safety standards. Our ATF Lane at Alltruck Loughborough successfully passed the DVSA Covid-19 site compliancy inspection with flying colours, ensuring a safe environment for all our clients.

To adhere to DVSA guidelines, we have implemented strict safety measures, including floor stickers and signs to ensure social distancing, and hand sanitiser stations throughout the site. Our staff will wear clean, disposable gloves when entering your vehicle's cab, and we may ask you to leave cab doors open for ventilation. We've also adapted our document handling procedures for safety. While these measures mean it’s not entirely 'business as usual', you can still expect the same friendly service, safe environment, and inspection quality that Alltruck plc has always been proud to deliver. We encourage a proactive approach to maintenance and are here to support you in keeping your fleet roadworthy. You can book your HGV MOT or discuss your maintenance needs by phoning Alltruck Loughborough on 01509 276 700 or emailing [email protected]. We look forward to assisting you soon!

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