DSB Mechanical Services: The MOT Test

Detailed description of the UK MOT Test for Cars and Motorcycles

Registration plates and Vehicle Identification Number* (VIN)

For registered vehicles the plate must be:

present
secure
not faded, dirty or obscured
be composed with correctly formed letters and spacing.

The VIN number must be:

permanently displayed
consistent
legible

* Required on all vehicles first used on or after 1st August 1980.

Steering

Inside the car checks:

Steering wheel and steering column:

steering wheel is in acceptable condition
steering wheel is securely attached to the steering shaft
upper bearings of the steering column are inspected for wear
Steering shaft is checked for excessive end float
The clamping bolts are all checked for security
split pins and locking nuts are also checked.
'free play' in the steering is checked
All flexible couplings and universal joints are checked.

Under bonnet checks:

This varies vehicle to vehicle; some of these items cannot be observed from under the bonnet on some makes and models.

security of the steering rack or steering box and its mountings
play in steering joints
Inspection of any other swivel joints which form part of the vehicles' steering system which can be readily inspected from under the bonnet.

Under vehicle checks:

All the steering joints are inspected by the Tester whilst the steering is loaded by turning the steering wheel from side to side.
Power steering systems are checked with the engine running
The security of attachment of the steering rack or steering box is checked both with respect to the tightness of nuts and bolts, and structural cracking or corrosion of the vehicle chassis where it is attached
Whilst the vehicle stands on special swivel plates the wheels are turned from lock to lock and checked to ensure that the wheels and tyres do not foul either the structure of the vehicle or any brake pipes or hoses
with the wheels jacked the wheel bearings are checked
steering rack gaiters and front outer constant velocity joint boots are examined
metal and/or rubber bushes are checked as are split pins, locking nuts and other locking or retaining devices which relate to steering components.

On some cars there will be rear wheel steering which is checked from beneath the car.

Horn

operation
control can be easily reached by the driver
loud enough
not a sequential multi-tone.

Lights

All required lights are checked for:

operation
condition
security

Side lights and headlamps:

are the correct type and colour
dip and aim.

Stop lights, indicators and hazard lights*

are the correct type and colour
do not interfere with each other in operation
driver's tell-tale works with respect to indicators, or there is an audible warning system.

Rear Fog lamps**

must be fitted to the centre or offside of the vehicle
tell-tale must work
must not be affected by other lamps and not be obscured
must be red.

Number plate lamps

All lamps fitted must be working.

Rear reflectors

There must be two red reflectors fitted reasonably symmetrically, securely attached and not obscured.

* Must be fitted to all vehicles first used on or after 1st April 1986, but if fitted, must be tested.
** Must be fitted to all vehicles first used on or after 1st April 1980.

Bonnet Catch

Reasons for Failure:

A bonnet that cannot be safely secured in the closed position
An excessively deteriorated, ineffective or insecure (bonnet) retaining device

Doors

Both front doors must be openable from the inside and outside and all doors must latch securely.

Tailgates, bootlids etc.

All these items, including the tailboards and dropsides of trucks must be securable in the closed position

Vehicle Structure

Body condition and security:

The body must not be so insecure or displaced so that it might lead to loss of control of the vehicle when driven, or be a danger to other road users.
There must be no dangerous sharp edges or projections caused by corrosion or damage which is dangerous to other road users including pedestrians.

Corrosion

A vehicle can fail with respect to corrosion for:

excessive corrosion in a 'prescribed area' — within 30 cms of certain safety related components, e.g. brakes, steering, suspension, seat belt mountings etc.
excessive corrosion not in a 'prescribed area', but which is likely to adversely affect the vehicle's braking or steering. 'Excessive corrosion' can mean a hole or a significantly weakened structure.

Seats

the driver's and the front passenger's seats must be secure
all seat backs must be securable in the upright position.

Brakes

Inside the car

Anti-lock braking system (if fitted) warning lamp is checked for:

function
sequence of operation

Footbrake

sufficient reserve travel on the footbrake
pedal rubber not worn to excess
correct operation of the servo assistance system

Parking brake

This could be hand or foot operated. Checked for reserve travel so that it doesn't reach the stops on application. The mountings will be checked for security and/or corrosion.

Under bonnet checks:

master cylinder and servo unit are checked for leaks with the engine on and the brakes applied
servo unit will be checked to ensure it is operating correctly
visible metal or flexible brake pipes will be checked for corrosion, condition, fouling or leaks

Under vehicle checks:

flexible brake pipes and any other metal brake pipes visible beneath the car are checked
discs and drums (external only) checked for condition and contamination
brake back plates and caliper securing devices are checked for condition and security
condition of the brake pads will be checked if visible
The assistant operates the handbrake and the condition of the linkages and/or cables is checked.
on some vehicles there will be a brake compensating valve beneath the car which will need to be inspected for fluid leaks

Brake performance check

The performance of the front and rear brakes and handbrake are checked for efficiency and balance using specialised equipment.

Windscreen

Includes all items affecting the driver's view of the road: the condition of the windscreen, the wipers and washers.

Chips or cracks in the windscreen directly in front of the driver, in the area swept by the wiper blades, are acceptable if they are less than 10mm in diameter. In the rest of the swept area, up to 40mm diameter damage is acceptable.

Official stickers (any used in connection with road enforcement, security or crime prevention matters) that are not readily removable are only a reason for rejection if they restrict the driver's view.

Washers and wipers:

operation
extent of area swept by the wipers
condition of the wiper blades

Mirrors

Not all mirrors on all vehicles are subject to Test, depending on the age of the vehicle. Those mirrors which must be checked must be

secure
visible from the driver's seat
not distorted or damaged so as to seriously impair the driver's view to the rear

Suspension

Under bonnet checks:

upper suspension joints
any other suspension components which can be inspected from beneath the bonnet

Under vehicle checks:

Applies to the front and rear suspension

no split pins or nuts missing, no components broken or excessively damaged
road springs are checked for condition
all suspension joints are checked for condition
shock absorbers must not leak and must be secure (the vehicle will be 'bounced' by the Tester to check that they damp the springs adequately).
The suspension is checked for wear by the assistant applying loads in various ways with the wheels jacked up whilst the Tester observes the result from beneath the vehicle.

Note: There are numerous different suspension systems, and the specific nature of any examination will depend to a large extent on the design of the suspension system.

Seat Belts

Most vehicles after 1965 must have seat belts. Irrespective of that requirement, all seat belts fitted to any vehicle must be inspected for:

security of seat belt mountings and locking stalks
security and operation of the locking/release mechanism
condition of webbing
retraction of the belt (it is allowed to manually feed it in).
Notes: 1. For technical reasons the inertia locking mechanism is not checked. 2. On some vehicles the belt is attached to the seat, in which case the security of the seat to the vehicle would also constitute part of the seat belt check.

Exhaust and Emissions

The exhaust system will fail the MOT if:

Part of the system missing or excessively deteriorated
A mounting is missing or damaged so it does not support the system
There is a major leak
The system is excessively noisy.

Emissions:
These are checked using specialised equipment, the details of the check depending on the year that the vehicle was first used on the road. Excessive smoking (checked visually) is a reason for failure.

Diesel smoke emissions are checked by using a smoke meter.

Fuel System

Any fuel leak will result in a fail. Checked under the bonnet and throughout the run of the fuel line from the fuel tank to the engine.

fuel filler cap must fasten securely
the seal in the cap must not be torn, deteriorated or missing
no other defect which could cause fuel to leak out

Tyres and Roadwheels

Tyre condition

The reason for failure with respect to tyre wear is:

"The grooves of the tread pattern are not at least 1.6mm throughout a continuous band comprising: the central three-quarters of the breadth of tread around the entire outer circumference of the tyre".

Tyres must be correctly matched with regard to:

type
size
structure

NB. type or structure but not both.
tyres on the same axle must be of the same structure and size.

Also examined:

general condition of tyre
condition of valve.
Tyres fail if they have serious cuts, bulges or other damage.

The wear on the tyre is checked with a tyre tread depth gauge to ensure compliance.

The tyres are examined to ensure that there is no fouling with any part of the vehicle.

Notes: Although under-inflation is not in itself a reason for failure, a brake test may be inadvisable because of possible damage, and it may affect headlamp alignment. The condition of the spare tyre is not part of the MOT.

Wheel condition

damage
distortion
cracks
distorted bead rim
securely attached to the vehicle
no wheel nuts or studs missing.
An externally fitted spare wheel or spare wheel carrier must not be so insecure that it is likely to fall off.

Motorcycle MOT Test Items

a) Sitting on machine check:

1. All controls, switches and horn
2. Front suspension, forks, handlebars and head bearings

b) At the front of the machine check:

1. Front lights and indicators
2. Front brake master cylinder (if fitted)

c) Place the machine on its stand and raise front wheel check:

1. Steering, front forks and head bearings
2. Front brake and wheel bearings
3. Wheel and tyre condition

d) Lower front wheel and go to right side of vehicle and check:

1. Frame, VIN, seat and foot rest
2. Exhaust system
3. Final drive (if fitted to RHS of machine)
4. Rear wheel, tyre and brake

e) Raise the rear wheel and check:

1. Rear wheel, rear brake/components and tyre condition
2. Rear suspension and final drive

f) At the rear check:

1. Rear position lamp(s)/stop lamp(s)/reflectors and indicators
2. Rear suspension
3. Registration Plate

g) On the left of the machine check:

1. Frame and foot rest
2. Exhaust system
3. Final drive (if fitted to LHS of machine)
4. Rear wheel, tyre and brake

h) At the front of the machine check:

1. Wheel alignment
2. Headlamp aim
3. Brake performance

If a sidecar is fitted it will also be examined in a manner specified by VOSA with respect to Security, Suspension, Wheel Bearings and Wheel Alignment.