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11 Local manufacture and repair code of practice

11-1 Scope and tasks certifiable by a local manufacturing certifier (HMXD)

Background and acknowledgement

The manufacture and repair code of practice was created in 2003 by the NZ Truck and Trailer Manufacturers Federation (TTMF). That code was adapted by the NZTA in 2019 to reside within the VIRM: Heavy vehicle specialist certification.


In the event of any contradiction, the Act, Regulations, Land Transport Rules and the original manufacturer’s repair or modification guidelines (manufacturer’s body builders’ manual) take precedence over this code. Persons repairing or certifying repairs to heavy vehicles must ensure that all applicable manufacturer’s recommendations are complied with and that no regulatory compliance is invalidated, even as an unintended consequence of complying with this code. Where there is disagreement between this code and the manufacturer’s body builder’s manual, or the repair procedure in the body builder’s manual is inappropriate, the repair must be referred to a HV engineering certifier with the appropriate category.

Repairers are obliged under Land Transport Rule: Vehicle Repair 1998, to repair vehicles in accordance with the Rule and the applicable requirements in the Rule. This rule also requires repairers to provide information or assistance to the Transport Agency when requested.

Range of tasks covered by this code

This Code of Practice applies to:

  • The minor repair of heavy motor vehicles currently registered in New Zealand.
  • The manufacture and/or fitting of new components covered by the Appointments Section.

This code provides procedural requirements and examples of acceptable practice for a range of common repairs and standard manufactured components. It is intended to supplement the recommendations of the original vehicle manufacturer in relation to vehicle repair techniques or standards and provides guidelines where manufacturer’s standards do not exist. It does not cover every eventuality.

Failure modes

The failure mode of a structural component of a HV, including the chassis, may be classified according to the following:


Failures that are unlikely to cause safety concerns and may be repaired according to good industry standard without welding and where certification isn't required. Repairs in this category are covered in this code.


Failures that may cause safety concerns unless repaired according to best industry practice, following either a properly designed repair specification or a pre- engineered solution reflecting industry best practice based on a detailed engineering analysis carried out by a HV engineering certifier with the appropriate category. Repairs in this category are covered in this code.


Failures with serious safety implications, including safety critical bolt-on items such as repaired steering or suspension items, that must always be repaired according to a repair specification based on a detailed engineering analysis carried out by a HV engineering certifier with the appropriate category. Repairs without an SoDC in this category are not covered in this code.

Note: Where a subsequent failure occurs in a repair that used a method selected from this code, it must be considered a critical failure and be referred to a HV engineering certifier with the appropriate category.  This is due to the safety risk as the initial repair was demonstrably not adequate and thus resulted in the subsequent failure showing there were unrecognised risk factors in the original repair.

The repairs covered by this code are typically of a structural nature requiring the replacement or repair of an item which usually involves some welding. It does not cover components that are attached using fasteners that can be replaced in a bolt-on, bolt-off manner. These components do not need certification except as noted above but it is the repairer’s responsibility that they are fit for purpose and meet the requirements of Land Transport Rule: Vehicle Repair 1998, of returning the vehicle to within safe tolerance of original manufacture. After market or pattern parts may not meet these criteria.

A repair carried out under this code cannot be used justify the alteration of a vehicle’s chassis rating.

Table 11-1-1 Tasks for HV manufacturer certifiers allowed in this code

Component/item – repair type



Damage to web stiffener with no significant attachments



Crossmember gusset with cracks in gusset



Crossmember with cracks – 1st repair



Crossmember with cracks – 2nd repair of same problem failure


Cracks in web - through crossmembers



Cracks in web - crossmembers butt to web



Chassis rail flange crack – in front/rear overhang (not load bearing)


Body component not part of monocoque framework



Cracked crossmember more than 300 mm from a suspension



Toweye weld (as per original)



Proprietary Components (using manufacturer’s instructions)

Suspension hanger, spring seat.



Unacceptable Repairs/Practices

Unauthorised welded attachments to suspension components.


Unauthorised bolted attachments to suspension components.


Ballrace/turntables – welded repairs.


Bolted Components



Bolted toweye


1. Simple items do not require certification if repaired/replaced.

2. LT400 required.

3. LT400 and SoDC.

Page added 9 December 2019 (see amendment details).