Since the changes to the brake performance test were introduced in June 2013, we have had a number of queries regarding the lack of brake data entry screens when testing Class 3 vehicles.
When MOT Comp was introduced, if the tester answered ‘Yes’ to the question “Is vehicle trike or quad within scope of section 9 of the Inspection Manual?” access to the brake data entry screens was prevented.
In June 2013, the trike or quad question changed to “Is the vehicle a three-wheeler or quadricycle?” For Class 3 vehicles the answer now defaults to ‘Yes’, because all three-wheelers are trikes by definition, including such vehicles as a Reliant Robin.
For Class 4s, the answer defaults to ‘No’, so when testing a quadricycle, this must be changed to ‘Yes’, which again will prevent access to the brake data entry screens. But why?
Many trikes and some quads have motorcycle type braking systems, with two separate service brake controls and therefore a minimum service brake efficiency of 30% from one system and 25% from the other. However, for Class 3 and 4 vehicles, MOT Comp calculates the service brake efficiency result based on the more typical 50% overall efficiency requirement.
As this could lead to an incorrect result, testers are required to calculate the brake efficiencies themselves, and where necessary select the appropriate Reasons for Rejection (RfR) manually using the component list.
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