MOT Test of coupling mechanisms and towing equipment (6)

Formerly MOT Test of Tow Bar (Towing Hook)

The tow bar is now part of section 6 of the new MOT Testing Manual – ‘Body, Structure and Attachments’.

All types of coupling mechanisms and towbars fitted to the rear of a vehicle, including fifth-wheel couplings will be checked.

Towing eyes are not Tested.

Tow ball covers will be removed to inspect the tow ball.

If coupling mechanisms are behind access panels in the bumper, bodywork or removable panel, they will be moved to inspect the coupling mechanism unless tools are needed to do this.

When checking coupling mechanisms, loose fitting mats or carpet inside the luggage compartment may be lifted.

Retractable towbars will be checked in their ‘in-use’ position. However, if tools are needed to do this, the Tester doesn’t need to do it.

If a tow ball or pin isn’t fitted at the time of test – because it’s detachable, it’s been unbolted or otherwise removed – but the attachment brackets are still in place, the brackets will still be assessed unless they have been deliberately rendered unfit for further use.

There might be movement (‘play’) in some detachable tow balls between the receiver socket and the tapered swan neck fitting, with up to 3mm movement measured at the ball end.

The following will be rejected:

pins, jaws or hooks that have worn by more than 25% of their original thickness
pin locating holes that have been worn or elongated by more than 25% of their original diameter
tow balls that are obviously excessively worn

Many ‘bolt-on’ type tow balls have accessory devices between the tow ball and its mounting flange. These will only be rejected if their fitment is clearly likely to adversely affect the roadworthiness of the vehicle and its trailer.

The following categories apply to defects in this section:

Defect	Category
a. A towbar component damaged, defective or fractured	Major
A towbar component: i. excessively worn	Major
ii. so worn it is likely to fail	Dangerous
c. A towbar attachment: i. defective or insecure	Major
ii. likely to become detached	Dangerous
d. A towbar safety device damaged or not operating correctly	Major
e. A towbar coupling indicator not working	Major
f. Towbar i. obstructing the registration plate or any lamp	Minor
ii. obstructing the registration plate so that it is unreadable	Major
g. Unsafe modification: i. to towbar secondary components	Major
ii. to towbar primary components	Dangerous
h. Coupling too weak	Major
i. The strength or continuity of the load bearing structure within 30cm of any towbar mounting bracket: i. is significantly reduced	Major
ii. is so weakened that the towbar is likely to become detached	Dangerous