Thursday, August 23, 2012

What Does an MOT Examiner (Ministry of Transport) Look For?

Inside the car
· Operation of lights.
Dip to main beam working, including the operation of the main beam warning light on dash (shows in blue). The operation of the rear fog light switch making sure in stays on and switches off, with the warning light showing up either on the dash or on the switch. Indicator switch is operated to make sure the warning lights are displayed on the dash and cancel ok.
· Horn operation. Must be audible.
· Wiper and wash operation. Must operate and washers must work and hit the screen, and wipers must clear the screen.
· Anti-lock braking system (ABS) if fitted. To check this, turn the ignition on, but don't start the engine. The light should be visual on the dash, with the engine running it should be off. (With Range Rovers and Land Rovers the light does not go off until you are moving).
· Foot brake operation. With this the tester will be checking the operation of your brake servo. With the engine off, operate the foot brake several times until the pedal goes hard. With your foot resting on the foot brake start the engine; you should feel your foot sinking on the brake pedal, which shows you the servo, is operating, as it should do.
· Foot brake and clutch pedal. Must have grip rubbers on the pedals to stop your foot from slipping off. · Handbrake operation. Must stay on and release with free travel still left in handbrake mechanism.
· Operation of front doors. Should be able to open both front doors from inside.
· Front and rear seats. The tester will check the security of the backrests to make sure they don't fall forward of there own free will, and will check the base for security on the anchor points.
· Play in the steering column. Must be no excessive play in the steering column bearings. To check this the tester will hold the steering wheel at these points on the steering wheel, which is at 15.00 and at 21.00 and will rock the steering wheel side to side and then will do the same at these points, 0.00 and at 18.00. Side movement would be next, in which the tester will move the steering wheel from lock to lock to check for free play in the steering system. You are allowed a certain amount, which normally occurs with vehicles fitted with steering boxes.
Out side the vehicle
· Checking the windscreen for defects. The examiner will check for cracks and stone chips. UK law is that anything bigger than 10mm in diameter on the drivers; side is a failure. Drivers side being zone A, which is from one side of the steering wheel to the other side of the wheel with vertical lines going up the screen. Zone B is passenger side, which should have nothing bigger than 40mm in diameter.
· Checking the wiper rubbers. By lifting up the wiper arms of the screen you can check the rubbers for damage. They should not be coming away from the blade, as this is a failure.
· Operation of doors. Must be able to open all doors from the outside and should be secure when shut.
· Seat belts. The examiner will extend all the seat belts fully and check for fraying and cuts to the webbing. Lastly fasten all the seat belts into their stalks making sure they are secure and cannot be removed until you press the release button.
· Checking structural points. With this, the examiner will check the top of the sills and the A and B pillars for any rot, which could weaken the vehicle, including seat belt anchorage points. Also will check the boot floor and rear panel for any rot.
· Checking the lights. All lights must work except the reverse lights and front fog lights, which are not a legal requirement. Failures on this are, bulbs not working, reflectors, which are broken and missing. Indicator bulbs showing a white light that's if the lens is clear plastic. Faded colour lenses or incorrect colour given, by having a broken lens or all lights incorrectly displayed at the same time, normally caused by a bad earth in the system.
· Headlight aim. This is one of the points you will not be able to check, as only the garages would have this equipment to check this.
Under the bonnet
· Structural check. Checking top shock absorber mounts for corrosion, and chassis. Slam panel at the front close to structural mounts. Bulk head for corrosion especially around the brake servo area.
· Brake pipes. The examiner will ask the assistant to operate the brake pedal with the engine running, firstly checking the brake fluid level then going onto checking for leaks from the system including brake servo vacuum pipes and also looking at brake pipes for excessive corrosion which could lead to brake failure and security. To fail pipes they must be badly corroded and also they tend to loose their thickness down to that fact. Please note it is down to the examiner to determine whether to pass or fail the pipes.
· Steering. Asking the assistant to rock the steering from lock to lock the examiner will be looking at the lower steering column universal joint (U/J) that's if one is fitted for any free play or a rubber mounting for any defects where it goes directly onto the steering rack or steering box.
Under the vehicle
· Exhaust system. Must be free of excessive leaks, i.e. cracked pipes or cracked silencers or joints, also must be secure on all mounts.
· Brake pipes and brake hoses. Looking for excessive corrosion and security as before on brake pipes and must not be fouling moving parts. Brake hoses must be free of deep cuts and bulges. Rule of thumb with brake hoses, to check cut bend hose to see if you can see the cord showing. If you can then it would be a failure. If in doubt! Then ask a garage.
· Brake load valve. This is fitted on the rear axle, which determines the amount of force applied to the rear brakes when you have weight in the back of the vehicle. To check this it, the arm must move on the valve via the spring attached to the axle.
· Chassis. This is pretty hard as there are certain set ups. Most four wheel drives have a separate chassis away from the floor pan while a car can have this integrated to all in one, making the outer sills a structural point of the vehicle. So if in doubt ask. Anyway the main point is this. You need to keep an eye out for major rot near structural points, like suspension plus sub-frames, steering, seat anchorages and seat belt anchorages. If in doubt! Then ask a garage.
· Suspension. There are various set up's for suspension, the most popular is independent suspension where each wheel as its own suspension arms, from a torsion bar going across the rear axle, to a leaf spring set up used on each individual wheel on the rear axle.
I think that is enough to be going on with, so I will tell you what to look out for on each individual one.
On independent suspensions, you will need to check all suspension bushes for condition and wear using a lever bar with the suspension hanging down and not under load.
The torsion bar set up is found on the rear of the vehicle, joining both the rear wheels together on the same axle. As with independent suspension it must be hanging down and free from load. You need to check the axle bushes for wear.
Leaf springs are normally found on the rear of the vehicle. The things to look out for are; cracks in the leaf springs, broken U- bolts and loose U- bolt nuts, which tighten them to the axle. Also you will need to check the shackle bushes for wear, which support the leaf spring at the front and the rear. To check this you will need a certain amount of load on the vehicles axle.
There are various set up's on shock absorbers where they are independent from the coil springs or the most popular which is when its integrated with the coil spring, which is commonly called a suspension strut. With shock absorber and suspension struts shocks you will need to look for leaks, the condition of the top and bottom shock absorber mounts for wear, also the operation comes into play. To check this the vehicle must be on the ground. Using your weight bounce up and down on vehicle on the side you want to test, and then let go and count the amount of times it takes to settle. You will need to look for no more than two bounces. (To check top strut mounts see Steering) Looking at the coil springs you will need to check that they are not broken, through corrosion and are sitting correctly.
Now onto Anti-roll bars, which are a part of a typical suspension system, this helps the vehicle on cornering and gives the vehicle good stability. This is a metal bar, which goes across the front of the vehicle and rear if fitted, joining both the front suspension arms and rear suspension arms together via links on the lower suspension arms. The actual anti-roll bar is also attached to either the sub-frame or body of the vehicle through rubber mounts. You need to check the links for security and wear, either in the ball joints top and bottom or rubber bushes for separation. The anti-roll bar support bushes will also need to be checked for condition and separation.
· Handbrake cables on the rear must be in good working order and must not be frayed. The cables must be supported via the brackets to the body.
· Steering. There are mainly two types the most common is rack and pinion, which is where the steering column goes directly into the rack, which then goes to your front wheels. The other is a steering box, which is commonly used on four-wheel drives, vans and heavy goods vehicles. This is when the steering column goes directly to the steering box, which then uses steering arms from there to your wheels.
Rack and pinion; With the vehicle still jacked up and resting on axle stands, you will need to check lower and top (If fitted) suspension arm ball joints which are attached to the hub assembly for wear using a lever bar, using the tyre to lever up on. Sometimes in this situation you will find no movement but if you jack up the suspension arm from underneath and lever up on the tyre any movement will show up. Next you will need to check the steering track rod end ball joint, this shows up when you move the steering from side to side using the wheel. You will need to look for play in the ball joint and steering arm coming from the steering rack. Sometimes you do get a certain amount of play in the steering rack arm, but as long as it's not excessive it should be fine. If in doubt ask a garage.
Steering rack gaiters on the steering rack need to be checked. The covers should be free from splits and secure on the rack.
Steering box; As above with the vehicle on axle stands, you will need to look at the drop arm ball joint coming down from the steering box as well as checking all steering rod ball joints and track rod end ball joints for wear plus checking the lower and upper suspension arm ball joints which are attached to the hub assembly.
Wheel bearings; The two things to check for are free play in the bearing and noise. Firstly at 12.00 o'clock and 6 o'clock positions on the tyre rock the wheel to check for play, which should be minimal. You're aiming at 1-5mm play. For noise, spin the wheel to check for rumbling noises coming from the wheel bearing.
Tyre condition; You will need to check all tyre sizes on the vehicle, excluding the spare for correct size, secondly checking the condition of the side walls for bulging and cracks which could show up the internal cords of the tyre, and thirdly the tyre tread for wear. U.K law states the tyre must have 1.6mm tread across three quarters of the tread. This has always been a sticky subject, so if you're not sure ask a garage.
Brakes; At this point the examiner will check your brake discs and pads for condition. The rule of thumb is if the examiner can visually see your pads then they will be checked. If the examiner can't see with out taking the hubcap of or the wheel then they won't be tested. To fail pads they would nearly need to be close to metal to metal with the disc. For brake discs they would need to be badly worn or badly corroded. Brake calipers are also checked for leaks and security.
Vehicle on the ground
Emissions; This is one of those items you can not check, the only thing you can check for is excessive smoke from the exhaust caused by engine wear (blue smoke) it has to be pretty bad to fail, in other words you can not see the vehicle behind you. Other than that it's down to the garage to test your catalytic converter for operation.
Brake roller test; Sorry folks, yep this is another test you can not perform as the garages can only do this on there equipment, but you can do a simple test and that's to make sure the vehicle is braking in a straight line. In other words the steering wheel is not pulling to one side when under braking, this will show up any binding brakes on the front.

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