Class B rigid with a brake imbalance, a worn tyre and an insecure battery
A 2017 Class B rigid (two-axle, 7,500 kg GVW, hydraulic brakes) is presented for its CVRT. On the brake roller test the service brake efficiency is 58% with a front-axle imbalance of 22%. The parking brake holds 18% efficiency. The nearside rear tyre has a tread depth of 1.4 mm across the central three-quarters and shows a deep cut in the sidewall approximately 30 mm long that does not expose the cord. The battery is held in place by a single strap that is loose, and the battery can be moved by hand. The presenter says the imbalance is 'normal for an old van' and asks you to pass it because he has a delivery route to complete.
1. Assess the brake results against the standard and state the outcome.
Read the worked answer
Service brake efficiency. 58% on a 7,500 kg rigid is below the required efficiency for a vehicle of this class. The service brake must achieve the prescribed minimum efficiency (for this class, well above 58%). This alone is a fail.
Front-axle imbalance. 22% imbalance between the front wheels is excessive. Imbalance means the vehicle will pull to one side under braking, which is a steering and stability hazard. This is a major defect.
Parking brake. 18% efficiency is low. The parking brake must hold the vehicle on a gradient; 18% is unlikely to meet the requirement. This is a defect.
Outcome. The vehicle fails on the service brake efficiency, the imbalance, and very likely the parking brake. These are braking defects and the vehicle must not be used on the road until repaired. The presenter's 'normal for an old van' comment is not a basis for passing - a 22% imbalance is not normal and is not acceptable.
2. Assess the tyre and battery findings and decide whether either changes the result.
Read the worked answer
Tyre tread. 1.4 mm across the central three-quarters is above the 1.0 mm legal minimum, so tread depth alone does not fail it. However, it is close to the limit and should be noted as advice.
Sidewall cut. A 30 mm cut in the sidewall that does not expose the cord is a defect if it is deep enough to be a structural concern. The test looks at whether the cut is likely to lead to failure. A 30 mm sidewall cut is significant - it should be assessed for depth and whether the cord is visible or likely to become visible. If it does not expose cord and is not likely to, it may be recorded as a minor defect or advice; if it is deep, it is a major defect. On the facts given (deep cut, no cord exposed), record it and assess carefully - do not dismiss it.
Battery security. A battery held by a single loose strap that allows movement is not securely fastened. A loose battery can short, arc, or become dislodged. This is a defect - it must be secured. It is a fail item.
Effect on result. The vehicle already fails on the brakes. The battery security adds a further defect. The tyre cut is recorded. None of this changes the outcome: refuse the certificate. The delivery route is a commercial matter; the vehicle is not roadworthy.