Towbar

Information 

This inspection applies to all types of towbar fitted to the rear.  It does not include emergency towing eyes. 

Tow ball covers must not be removed to facilitate inspection of the tow ball. 

If a tow ball or pin is not fitted at the time of test, e.g. because it is detachable, or has been unbolted or otherwise removed, but the attachment brackets are still in place these should still be assessed. 

Assessing wear 

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.  Pin locating holes should be rejected if they are worn or elongated by more than 25% of their original diameter.  This criterion also applies to pins and brackets for any height adjustment mechanisms. 

For tow balls the amount of acceptable wear is considerably less.  However, a tow ball should only be rejected if a visual assessment indicates that the tow ball is obviously excessively worn. 

There may be 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. Reason for Rejection 4a should only be used where play is greater than this. 

Inspection of components 

It may be necessary to inspect some components from inside the luggage compartment.  No covers or panels shall be removed to facilitate the inspection of any components, including tow ball covers. 

Security of attachment 

All parts of the towbar assembly should be securely mounted using fixings of an appropriate size and type. 

Trailer electrical couplings are tested under Section ‘Electrical Wiring and Equipment’ 

Method of Inspection 

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. 

Note: Some locking devices are not obvious. In such cases, the vehicle presenter should be advised of any evidence of disturbance or insecurity. 

4. On detachable tow balls: 

a. check for play between the tow ball arm and its receiver socket 

b. visually assess the condition of any quick release mechanism. 

Note: Quick release mechanisms must not be operated, only visually assessed. 

5.On height adjustable or swivelling towbars, check: 

a. for presence, and security of locating or swivel pins 

b. locating or swivel pins and brackets for excessive play or wear 

c. 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. 

7. Check the towbar assembly for any inappropriate repair or modification. 

Note:  Locking pins or safety devices must not be removed, but checked as far as possible 

that they are fit for purpose. 

Reason For Rejection

		Reason for Rejection	Deficiency Category
1		A towbar component insecure, fractured or excessively:
		Worn	MAJOR
		Corroded	MAJOR
		Damaged	MAJOR
2		Towbar assembly is attached to the vehicle structure using a mounting, support or fixing which is obviously of an inappropriate size or type.	MAJOR
3		Towbar obscuring the registration plate or any lamp	MINOR
4	a	Retaining device missing or insecure	MAJOR
	b	Locking device missing, insecure, inadequate or damaged to the extent that its operation is impaired.	MAJOR
5	a	Excessive play between a detachable tow ball and its receiver socket	MAJOR
	b	a quick release mechanism that does not secure the tow ball arm as intended.	MAJOR
6	a	A locating or swivel pin missing or insecure	MAJOR
	b	excessive play or wear in a locating or swivel pin or bracket	MAJOR
	c	a locating or swivel pin retaining device missing or insecure.	MAJOR
7		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.	MAJOR
8		A towbar assembly inappropriately repaired or modified such that it is likely to adversely affect the roadworthiness of the vehicle/trailer combination.	MAJOR