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To ensure that you have a compliant and efficient MOT testing station for cars, caravans and passenger vehicle MOT testing requires the right equipment, facilities and training to ensure compliance with industry regulations. A crucial aspect of any MOT testing centre is of course the MOT bay, where the MOT testing and inspection of vehicles take place.

We look at the garage equipment you need to ensure your garage business remains DVSA compliant so that you and your mechanics are able to perform Class 4 MOT tests efficiently and safely.

What vehicles are covered by a Class 4 MOT Bay?

This type of MOT Car is mostly used for cars, but can also be used for motor caravans, taxis and ambulance MOT testing, as well as passenger vehicles with up to 12 seats.

As shown in the table below, the Class IV MOT Bays cover a large percentage of the standard vehicles on the UK roads today and also a few that may surprise you, like 3-wheelers over 450kg!

Vehicle Vehicle class Age first MOT needed (years)
3-wheeled vehicles (over 450kg unladen weight) 4 3
Cars (up to 8 passenger seats) 4 3
Motor caravans 4 3
Quads (max unladen weight 400kg – for goods vehicles 550kg and max net power of 15kw) 4 3
Dual purpose vehicles 4 3
Private hire and public service vehicles (up to 8 seats) 4 3
Ambulances and taxis 4 1
Private passenger vehicles and ambulances (9 to 12 passenger seats) 4 1
Goods vehicles (up to 3,000kg design gross weight) 4 3
Class 4 vehicles (9 to 12 passenger seats) with a seat belt installation check 4a n/a

For anything larger than a Class 4 Passenger Vehicle MOT, up to a goods vehicle, you will likely need a Class 7 MOT Bay.

What Garage Equipment is Required for Class 4 MOT Bays?

To carry out MOT tests on cars and other Class 4 vehicles in the UK, you need to have an approved Class 4 M.O.T. Bay.

The inspection process and rules for cars & passenger vehicles (class 4 vehicles) MOT tests can be found in the DVSA “MOT Inspection Manual for Cars and Passenger Vehicles“. It includes requirements for equipment, and inspection procedures including supplementary tests for buses and coaches, as well as tests for structural integrity and corrosion.

Approved equipment requirements and recommendations for Class 4 MOT testing bays include

As well as the following to meet the minimum MOT testing service IT specification as set by the DVSA:

  • Computer, laptop or tablet
  • Internet connection
  • Printer

Bear in mind that any new garage, or garage that has changed ownership is required to add or upgrade to DVSA Approved Connected MOT Equipment.

MOT testing premises also require:

  • Proper lighting
  • Ample ventilation
  • Sufficient space for the testing area, and surrounding each piece of MOT testing equipment

MOT testing personnel requirements include

Other Equipment for Class 4 MOT Garages

  • Tyre Changer (recommended but not a Class 4 MOT Bay requirement)
  • Wheel Balancer (recommended but not a Class 4 MOT Bay requirement)

Class 4 Vehicle Lift or Inspection Pit

You will either need an in-ground inspection pit otherwise a suitable MOT lift, often known as a car lift or MOT ramp, is the most common way to raise a vehicle to allow the mechanic to work more easily underneath or to the side of the vehicle during the inspection.

While there are many different types of automotive lifts, three of the most common in use by garages are four-post liftstwo-post lifts and scissor lifts.

For Class 4 MOT we would usually recommend a 4-post MOT lift for the most robust, stable support of the vehicle, and easy access during the MOT test.

Brake pedal application devices

The Brake Pedal application device, also known as the Brake Pedal Depressor is a DVSA-approved tool for depressing the brake pedal on a vehicle to hold the brakes on, without a person needing to be sat inside the car.  The benefit is that it means any test that requires the brakes to be applied (such as testing the brake lights for example) can be carried out by one person, instead of two, allowing more efficient use of the mechanics within the garage.

Brake Pedal application devices are often supplied with other garage equipment also, including wheel alignment machines, meaning you may not need to purchase this separately as you may already have one.


Decelerometers are handheld electronic devices that can be taken in a vehicle during a test drive and brake test, and they will test the braking efficiency by calculating the rate of deceleration. This should be used where a plate brake tester or roller brake tester is unavailable or unsuitable to perform this test.

There are 3 categories of decelerometers:

  • category A is approved for all classes of vehicle
  • category B are approved for class 3, 4, 5 and 7 vehicles
  • category C are approved for class 1 and 2 vehicles

Therefore for a Class 4 MOT Bay, you would need either a Category A or Category B decelerometer.

Diesel Smoke Meters & Exhaust Gas Analysers

Often simply referred to as Emissions Testers for MOT Bays, these gas and smoke meters are machines responsible for ensuring that vehicles meet emissions standards. They test the emissions of vehicles, collect data, and report the results to the garage and DVLA as part of the MOT. They are used by garage mechanics and MOT Bay engineers, vehicle manufacturers, and vehicle testing facilities.

The goal of an emission test is to help reduce the number of harmful pollutants in the environment, in order to lower the overall impact humans have on the planet.

As part of the DVSA rollout of connected MOT equipment, from 1 May 2021, exhaust gas analysers and diesel smoke meters have been able to connect directly to the MOT testing service, and for any new MOT Bay or an MOT Bay under new ownership, the Emissions Tester has to be connected.

Class 4 Headlight Tester

Headlight beam testers are used to test the intensity, quality and angle of the light produced by car headlights.

They are also used to test the shape, size, and colour of the light produced by the headlights, and to ensure the beam complies with the DVSA MOT testing requirements ensuring that the lighting output is uniform and does not cause glare. Headlight beam testers have become a standard industry instrument, and Class 4 car headlight testers can usually also be used for class 1 & 2 motorcycle MOT testing also.

Class 4 Plate Brake Testers

Plate brake testers are less popular than roller brake testers, but can be used for vehicles with permanent 4-wheel-drive systems, and consist of a set of metal plates installed on the ground, which simulates road surfaces. During a brake test, a vehicle is driven onto the plates, and the brakes are applied under controlled conditions. The Plate Brake Tester measures various parameters, including brake force, brake imbalance, and efficiency, providing valuable information about the condition of the vehicle’s braking system, and the stopping ability of each of the vehicle wheels.

Class 4 Roller Brake Tester

A  roller brake tester is used to test the brakes on each wheel of a car or other vehicle during the MOT test to the standards set by DVSA.  They will check that the braking ability of the car is sufficient to slow and bring the vehicle to a safe stop.

These roller brake testers usually have a built-in weighing scale so that the device knows when the car is driven onto the rollers, and when it has been removed, to prevent the rollers from spinning when unsafe to do so, and some are also remote-controlled for added safety.

Tow Bar Socket Testers

Tow bar socket testers are used in Class 4 MOT bays to evaluate, where fitted, the functionality and safety of tow bar electrical connections.

These testers are designed to check the electrical circuits and wiring within tow bar sockets, ensuring they meet the required standards and regulations. During an MOT inspection, a tow bar socket tester is connected to the vehicle’s socket, and a series of tests are conducted to assess various parameters such as lighting, indicators, and brake functions. This comprehensive assessment helps identify any faults or deficiencies in the tow bar socket’s electrical system, ensuring that it operates correctly and reliably.

Tyre Tread Depth Gauges

Tyre tread depth gauges are used to measure the depth of the remaining tread on vehicle tyres. These gauges are designed to accurately determine the amount of remaining tread on the tyre’s surface, which is essential for maintaining optimal traction and grip on the road.  Tyre tread depth gauges typically consist of a small handheld device, some are mechanical and others electronic with a digital display.

To use the gauge, the probe is pressed into or in the case of an electronic gauge it is passed over the tread grooves, and the depth of the tread is read off the scale or displayed digitally. The depth of the tyre tread is checked to ensure it meets the legal tread depth requirements or if it is worn and in need of replacement to pass the MOT test.

Wheel Play Detectors

Play detectors, also known as Shaker Plates are hydraulically operated devices that are fitted to a vehicle lift or inspection pit.

The wheel play detectors are used to check for wear and play in suspension and steering joint components. To do this, they move the wheel in different directions. A wheel play detector can detect when the car is out of alignment and shake the wheel to help correct it.

Play detectors are used for use in one-person testing lanes (OPTL) and are available as standalone items, which can be used with pit-based ATL bays, or you have the option of adding it to your current MOT lift.

Class 4 MOT Tester Training

Depending on your role within the MOT testing station you will require different levels of MOT training.

  • Authorised Examiner Designated Manager (AEDM) Training: This can be either the business owner or employee if you have multiple sites, and this person can optionally also be the MOT tester
  • MOT Tester Training: An MOT Tester can be either the business owner or an employee, and this person can also be an AEDM
  • MOT Annual Assessment Training: If you’re already an MOT tester, you must complete training and pass an annual MOT tester assessment between April and March every year

Class 4 Tyre Changer

Although not a DVSA requirement for MOT Testing, tyre changers allow for quick and easy replacement of car tyres, which can make tyre changing such a quick and easy process when being done as part of the work necessary to pass a Class 4 vehicle through an MOT test. Car tyre changers come in different types and sizes, ranging from manual models to fully automated machines. They are designed to handle many sizes of vehicle wheels and tyres. Some models feature advanced technology, such as a pneumatic bead breaker and tyre press, which make the tyre-changing process even faster and more efficient, and many can also have motorcycle adapters fitted for use on motorcycle tyre changing also.

They assist the tyre fitter in securely holding the vehicle wheel, usually by way of a clamp, such that either manual or automated tools can be used to level the tyre off the rim, and subsequently do the reverse to put a new or repaired tyre back onto the wheel rim.  With automated tyre changers, they will also rotate the tyre during the removal and re-application process of the tyre.

Almost all of the tyre changers sold by Concept Garage Equipment can be used for Class 4 vehicle tyre changing, but do check if you plan to change oversized, low profile or run-flat car tyres that the tyre machine you choose is capable of these.

Class 4 Wheel Balancer

Wheel balancers are not a DVSA requirement for MOT Testing, but these compact balancing machines can make all the difference when it comes to ensuring a smooth and safe ride.

The wheel balancer is used to spin each wheel of the vehicle to assess the weight of the wheel with the tyre installed to check for uneven weight distribution across the wheel’s circumference.

The tyre fitter would use the machine to identify the lightest point on the tyre’s rotation and apply small metal weights to the tyre’s rim to neutralise the weight differences and cause an even weight across the whole wheel circumference.

Almost all of the wheel balancers sold by Concept Garage Equipment can be used for Class 4 vehicle wheel balancing, but again do check if you work on unusual vehicles with oversized or special wheels and tyres to ensure you get the correct balancer for your garage.

What are the Class 4 MOT bay dimensions?

The length of the Class 4 MOT Bay will depend on your choice of equipment and the size, type and layout of the premises.  You may prefer a lift over an inspection pit for example, or you may wish to have 2 lifts and one roller brake tester for maximum efficiency when performing multiple MOT tests.  For this reason, we recommend a visit to your premises from one of our MOT experts to have your potential MOT Bay measured and planned out correctly along with advice and guidance on the MOT equipment that you will need for a Class 4 MOT Bay, along with any additional requirements you would like to include.

However as a guide to the dimensions of your Class 4 MOT Bay:

Class 4 MOT Bay dimensions with MOT Ramp size requirements

Height requirement – This can be not very clear at times so the easiest way to explain this is if you were to imagine a glass box around your MOT ramp.

The glass box must be extended 500mm from the outer edges of each platform left and right, 500mm to the rear of the ramp and 1000mm out from the drive on the end of the ramp. This glass box must be 3800mm high.

If that glass box fits where the ramp is to be installed, then the height is not a problem. If anything enters the glass box, this is a problem and it may cause DVSA (Driver and Vehicle Standards Agency) to reject your application. There may be a solution should you face this problem by using a slightly different configuration on the MOT bay’s layout, but this depends on the space available within your premises.

Other essential Class 4 MOT Bay dimensions to know

  • The overall width of a class 4 MOT bay is 3600mm
  • Vehicle entrances and exits must be a minimum of 2400mm in height and wide
  • Headroom over lift 3800mm as explained above
  • Headroom over brake test standing area 2400mm
  • Brake test standing area width 2400mm
  • Brake test standing area length 9000mm – This can be part of your ramp if the ramp is recessed into the floor and level with your roller brake tester

Class 4 MOT Bay dimensions with an Inspection Pit

Height requirement – When using an inspection pit instead of a ramp then the height considerably reduces from 3800mm to 2400mm.

The use of a pit may be the only option available to you if you don’t have the required height or width within your premises.

Again, using the glass box to help, you will need to imagine your glass box 3600mm in width and 2400mm high the whole length of your MOT bay. If that glass box fits, then there is no issue.

Class 4 Inspection Pit size requirements

  • A working length of at least 3900mm
  • A width of at least 760mm and not more than 920mm over the working length measured across both pit walls
  • A depth of at least 1500mm and not more than 1800mm, over the working length
  • Adequate access for personnel to enter the pit which does not intrude on the working dimensions

Essential Class 4 MOT Bay dimensions with inspection pit

  • The overall width of a class 4 MOT bay is 3600mm
  • Entrances and exits must be a minimum of 2400mm in height and width
  • Headroom over brake test standing area 2400mm
  • Brake test standing area width 2400mm
  • Brake test standing area length 9000mm – Part of this can be either side of your pit

Help with your Class 4 MOT Bay

If you are looking to set up a Class 4 MOT Bay for cars and passenger vehicles, or upgrading an existing Class 4 or Class 7 MOT Bay to include newer connected MOT equipment and need some information, helpful free advice or additional garage or MOT equipment give Concept Garage Equipment a call, we would love to help you get your Class 4 MOT Bay set up and paying for itself as soon as possible.

We can offer you advice over the phone at 0113 469 0572, we have Class 4 MOT equipment for sale online and over the phone, including delivery, installation and staff training in the correct use of the MOT Bay or garage equipment and can offer complete project management of your MOT Bay build, installation and training, we can remove all your headaches along the way. 

Call us today on 0113 469 0572 or use the website contact form today, we are here to help.