Update to brake modification requirements in the in-service and HVSC VIRMs
On 1 April 2021 an HVSC VIRM change introduced a new version of Technical bulletin 4 (TB4) in the heavy vehicle specialist certification VIRM and some changes to heavy vehicle and trailer brakes in the in-service VIRM. The introduction of the new TB4 was aimed at providing one source of information regarding heavy vehicle brake certification, where alteration or modifications are carried out on both new and in-service heavy vehicles.
The introduction caused unintended actions and unexpected responses from both heavy vehicle certifiers and vehicle inspectors resulting in many vehicles being delayed for certification and failed at CoF inspection.
The revised TB4 now requires the heavy vehicle manufacturer or the approved representative of the manufacturer to supply documentation that gives details of the braking system for the vehicle being modified, the HVSC uses this document to support the changes being made before signing off the LT400 for the work.
The changes to the in-service VIRM return the reasons for rejection to pre-1 April 2021, with tables 8-1-6 (heavy vehicles) and 5-1-6 (heavy trailers) largely having changes to the modification definition below the tables.
These changes cover all vehicles from their next brake modification certification or in-service inspection.
These changes are in effect from 10 January 2022.