Tow bar mountings are a little funny in the respect that they are a structural component, therefore need testing or examination. Testing requirements are defined by legistation which now ensure the manufacturers conform to both quality and operational requirements, or life cycle and duty cycle. These are performed to a standard set over 100,000 operational cycles, and the degredation is noted, so this is not a function of the MOT test.

Structural testing having been undertaken by manufacturers means MOT testers ignore it unless there is obvious damage to the towbar itself. Mountings are a different issue, these are generally accepted as those for other structural testing or examination, i.e. anything corroded within 300mm of the mountings mean a fail. This is taken a step further by MOT testers, anything corroded in front of the tow bar mounting may incur a fail as this means the chassis or subframe fails the MOT on dangerous corrosion issues, this being general corrosion.

In reality it is often a major job to access all the system mounting points unless a lot of the interior is stripped out, so again it is generally omitted unless an obvious defect is found, such as a loose towbar.

All in all the tester will most likely perform his usual checks, fail the chassis for excess corrosion, and the towbar aspect will be a glance and pull on the towbar to check to see if it is tight.