What are the specific criteria used to evaluate service brake performance and efficiency during the MOT inspection for private passenger and light commercial vehicles, particularly in terms of vehicle weights, wheel locks, and braking devices?

The MOT (Ministry of Transport) inspection for private passenger and light commercial vehicles includes a comprehensive evaluation of service brake performance and efficiency. This assessment is crucial to ensuring safe operation and involves specific criteria related to vehicle weights, wheel locks, and braking devices.

When conducting the brake test, the weight of the vehicle is a critical factor. For standard vehicles, you can use the DGW (Deadweight Gross Vehicle Weight) provided by the manufacturer, which is usually 2,600kg for Class 7 vehicles. However, if the vehicle has been converted into a motor caravan or ambulance, its test weight may be unknown, requiring special consideration during the inspection.

The brake tester should position the wheels of the first axle in the brake rollers and run both sets of rollers together in a forward direction until the vehicle is aligned. During this process, it's essential to check for any significant brake effort recorded from a wheel without applying the brake. If a vehicle is ejected from the brake rollers, the test should be repeated using an alternative procedure to ensure all testable elements are adequately covered.