MOT Testing Towbar for Class lll, lV, V & Vll
The MOT test for the above classes now includes an inspection of the towbar. The overall objective is
to ensure that when a vehicle is presented for test with a towbar installed, it must not be in an
obviously unroadworthy state. Details of the inspection methods are as follows.
This inspection applies to: all types of towbar fitted to the rear of a vehicle. It does not include emergency towing eyes.
Wear in a pin, jaw or hook should be regarded as excessive if the thickness of the metal at any point is reduced by more than 25% of the original thickness. This also applies to pin locating holes if they are
worn or elongated by more than 25% of their original diameter. These criteria also apply to pins and brackets for any height adjustment or swivel devices.
For towballs the amount of acceptable wear is considerably less. However, a towball
should only be rejected if a visual assessment indicates that the towball is obviously excessively worn.
Play in detachable towballs Some detachable towballs have play between the receiver socket and the tapered swan neck fitting, with up to 3mm movement measured at the ball end.
Reason for Rejection 4a should only be used where play is greater than this.
Inspection of Components
No covers or panels shall be removed to facilitate the inspection of any components, including towball covers. However, it may be necessary to inspect some components from inside the luggage compartment, including lifting of loose fitting mats or
carpets. Quick release mechanisms must not be operated, only visually assessed.
1. Visually assess the towbar for wear and pull on the towbar and/or its
mountings to check for security, corrosion, fractures or damage.
2. Check the towbar assembly is attached to the vehicle structure using mountings, supports and fixings of an appropriate size and type.
3. Check the presence and security of: a. retaining devices e.g. nuts & bolts. b. locking devices e.g.
split pins, 'R' pins.
4. On height adjustment or swivelling towbars, check: a. for presence, and security of locating or swivel pins. b. locating or swivel pin retaining devices for presence and security.
6. Check the condition of the body and chassis in the vicinity of the towbar mountings.
Reason for Rejection
1. A towbar component insecure, fractured or excessively: worn corroded or damaged
2. Towbar assembly is attached to the vehicle structure using a mounting, support or fixing which is obviously of an inappropriate size or type.
3.a. Retaining device missing or insecure. b. locking device missing, insecure, inadequate or damaged to the extent that its operation is impaired.
4. a. Excessive play between a detachable towball and its receiver socket. b. a quick release mechanism that does not secure the towball arm as intended.
5. a. A locating or swivel pin missing or insecure. b. excessive play or wear in a locating or swivel pin bracket. c. a locating or swivel pin retaining device missing or insecure.
6. Any deliberate modification, excessive corrosion, damage, fracture or inadequate repair of a load bearing structure or supporting panelling within 30cm of the towbar mountings, which affects its strength to the extent that the security of attachment of the towbar is significantly reduced.