How much is in the MOT?

[Meatyfool]

I'll PM MonsterMork about this post as I believe he is an MOT assessor.

How much of the following list would be covered by an MOT?

It is the list of service jobs for a Nissan Leaf (electric car).

I'll explain why I would like to know in a later post.

Every 12 months/18k miles

Replace OK, this won't happen

Air con filter at specific mileage

Inspect

Headlamp aiming
Brake system and fluid
Charging port
Cooling system
Reduction gear oil
EV battery usage report
Computer diagnosis
Brake pads rotors and other brake components
Foot brake for free play stroke and operation
Parking brake for operation
Body corrosion

Every 24 months/36k miles

As above plus

Replace OK, this won't happen

brake fluid
Air conditioner filter

Inspect

Charging port rubber cap
Steering gear and linkage axle and suspension parts
Drive shaft boots

After 5 years/54k miles

Replace OK, this won't happen

coolant system coolant

Meatyfool..

[bungeejumper]

Any special reason why you won't replace the brake fluid? Terminal depression? Feelings of sublime invincibility? Or just feeling lucky?

I could show you some stacked hairpins in Europe that might change your mind. Always change the fluid, every two years or whenever I buy a used car. Little things can mean a lot. Everything, in fact.

BJ

[MonsterMork]

OK. from a purely MoT point of view, not service, just MoT:

Every 12 months/18k miles

Replace OK, this won't happen

Air con filter at specific mileage - no, external visual inspection only in passing whilst checking inside "engine bay" area on other items

Inspect

Headlamp aiming - yes, tested, including the height adjuster operation
Brake system and fluid - yes, visual inspection, along with prodding and poking and wiggling, and brake efficiency test*
Charging port - yes(ish), visual inspection for safety/corrosion, but no electrical test
Cooling system - no, external visual inspection only in passing whilst checking inside "engine bay" area on other items
Reduction gear oil - no
EV battery usage report - no
Computer diagnosis - no, only pootery diaggy bit of interest is a warning lamp on the dash, or a message on the dash telling of an issue
Brake pads rotors and other brake components - yes*
Foot brake for free play stroke and operation - yes, stroke not measured but assessed for whether there is sufficient reserve travel*
Parking brake for operation - yes, including operation and security of the parking brake lever*
Body corrosion - yes

Every 24 months/36k miles

As above plus

Replace OK, this won't happen

brake fluid - yes*
Air conditioner filter - no, external visual inspection only in passing whilst checking inside "engine bay" area on other items

Inspect

Charging port rubber cap - no
Steering gear and linkage axle and suspension parts - yes
Drive shaft boots - yes

After 5 years/54k miles

Replace OK, this won't happen

coolant system coolant - no, visual inspection only in passing whilst checking inside "engine bay" area on other items



* - brake systems:
Brake fluid check is only an external visual one for contamination, level, and for any leaks to pipes/hoses/master cyclinder anywhere on the vehicle. We are NOT allowed to remove the master cyclinder reservoir cap to inspect and test the fluid, NOR are we allowed to remove access panels/covers to get to reservoirs which may normally be covered or hidden from direct sight.
Hoses, pipes and lines etc are visually assessed, along with prodding and poking etc, for security of mounting, leaks, corrosion, fraying, chafing and rubbing, cracking, bulging under pressure and so on. We may use a corrosion assessment tool or brake pipe tool where required to lighly scrape surfaces to inspect potential corrosion and assess whether we believe the wall thickness of a pipe has been reduced.
Brake discs and pads and calipers are visually inspected (can be measured if desired if accessible with a tape measure or ruler), along with a tap, wiggle, prod and poke, and attempted movement with a small pinch bar if deemed necessary. Drums and their back plates ditto, but we DO NOT visually inspect or measure brake drum shoes (or handbrake shoes) except for external wear indicators (summat not seen on cars since the 1970's, and even then pretty rarely). Visual inspection of brake drum shoes would require removal of the wheel and drum, summat we are not allowed to do during the test. Some brake calipers incorporate the handbrake into them (mostly on vehicles with rear brake discs), and the handbrake "shoe" for these systems is therefore the brake pad, so subject to the brake disc/pad check as mentioned.
Final brake system check is on a rolling road (usually) to check service brake (foot brake) and parking brake (hand brake) efficiency and any bind, grab, lag or fluctuation in operation. Some vehicles are not suitable for a rolling road test, and are checked with a decelerometer machine during a road test. Example: a warped brake disc may not be visually noticeable, but will show up on a rolling road check, or be felt through the brake pedal or by affecting steering on a road test.

You asked about "reduction gear oil" - only checked if it is leaking, and even then we do not check the levels or condition; we only want to make sure it is not escaping into the outside world.

We are not allowed to make repairs to a vehicle during a test. The only "repair" sort of thing we can do during a test is make minor adjustments to headlamp aim.

Hope this is of some help.

TesterMork

[jfgw]

IIRC, a point made by MonsterMork in a previous post (I'm sure he will correct me if I am wrong) is that brake pads can be thick enough to pass an MOT (1.5mm?) but be below the vehicle manufacturer's specification.

Julian F. G. W.

[MonsterMork]

IIRC, a point made by MonsterMork in a previous post (I'm sure he will correct me if I am wrong) is that brake pads can be thick enough to pass an MOT (1.5mm?) but be below the vehicle manufacturer's specification.

Julian F. G. W.

Correct, brake pad minimum thickness is indeed 1.5mm for MoT purposes, at which point you get a Dangerous fail. Please note that pads which have squealers (the wee metal tab that will eventually rub on the disc when the pad wears down, more correctly called wear indicators, and start squealing like a banshee) will get a Major fail once the squealers hit the disc, even if the pad itself is well above 1.5mm - the manufacturers build in a tolerance level at or above MoT minimum, and will most likely have the squealer set at their own designed minimum depth. These depths are for the friction material of the pad, not the complete pad itself. And no, the metal backing part of the brake pad is not considered as being friction material! (Yes, testers have been called out by owners who thought it was 1.5mm including the backing .... )

Section 1.1.13

https://www.gov.uk/guidance/mot-inspect ... ion-1-1-13

Note also that brake discs do not have a set minimum thickness, the manual stating "A brake disc or drum must be significantly worn before you should reject it. Being worn below the manufacturer’s recommended limits is not a reason in itself.". See section 1.1.14 (continue down the page on the above linky).

MM

[sg31]

Just a general point on wear items. At what point do you replace brake pads and tyres etc? I don't mean the legal limits just when is it wise to replace.

The reason I ask is that I had a Mercedes which went in to the main dealer for service and they suggested I needed new tyres when they had 5 or 6mm of tread on them. I refused as to my mind that was enough. I never gave it another thought but this year my wifes car went in to a very good local garage for a service and MOT. They asked her if she wanted the brake pads changing as they were worn down to 50%. She said yes, when she told me about it I thought that was plenty remaining and would have left them alone as it's a low mileage car.

What do the rest of you do? When do you replace?

[MonsterMork]

Just a general point on wear items. At what point do you replace brake pads and tyres etc? I don't mean the legal limits just when is it wise to replace.

As a general rule of thumb I personally advise on tyre depth and brake pad depth at 3mm, and have done ever since I started testing, although other testers may not do so, choosing lower or higher limits to advise at, or not even at all. There is no set limit from DVSA at which MoT testers should advise, it is a personal choice.

At 3mm you are at double the limit for pads, and virtually double for tyres, and they will be "significantly and obviously worn". Bear in mind that most car tyres start life at 8mm deep, and brake pads generally 8 to 12mm. A quick bit of maffermatics and you soon realise that 3mm for tyres means they are 63% worn, and pads 63% to 75%. Visually alone you should know to change when you compare old to new!

It seems my 3mm limit is borne out by the RAC, at least for tyres:

https://www.rac.co.uk/drive/advice/tyre ... yre-tread/

As for brake discs then a good lip on the edge of the disc is always an indicator to needing change. The tinterweb will be able to tell you what the manufacturers wear limits are, and what the discs start out at. Many discs are hard, if not impossible, to get to the inside face of. If possible measure the lip depth on the outside of the disc, or at least guesstimate, then double it to account for inner wear. Subtract from the original depth, compare to the manufacturers specified limits and hey presto. Please note that if using the likes of Halfords, GSF, Euro Car Parts etc to find sizes, some of them list the minimum thickness alright, but not the original thickness, only the total disc height including the centre mounting boss, which might make you throw away a brand new disc!

MM

[sg31]

Thanks MM, that seems perfectly reasonable.

[Meatyfool]

MM,

Many thanks for replying.

As some of you may have guessed, I asked the question about what service actions are part of the MOT because electric cars are significantly simpler mechanically and so require less service – I’m not saying NO service, but less service.

There are in fact two aspects to servicing. Firstly, the safety/security/comfort aspect (“Am I safe? Are my loved ones safe? Am I a danger to others?”) . Secondly, when it comes to resale, no-one wants to buy a lemon (a full service history is an indication the car has been taken care of).
An internal combustion engine does require regular servicing to maintain smooth running and efficiency. So many moving parts! In comparison, note that there is no service component at all in the list above for the electric motor on the Leaf!

If (say) I don’t pay for a service for five years but at the end of the period pay for an inspection of the car (AA/RAC type thing), then that document will be as beneficial (if not more so) than a FSH.

Going back to the safety aspect, would I leave my brakes unchecked for 5 years? No way. If I know there is little wear, I might last two on the basis that my normal travel is country roads at no more than 55mph, and I drive efficiently making extensive use of the regenerative braking. Brake wear is much less on an EV.

However, I’d far more likely ask a local independent garage to do a “brake service” and charge me accordingly for their time.
If I had a brand new electric car under warranty, would I service it to keep the warranty safe? I’ll worry about that if it ever happens again!

Lastly, air con filter replacement is do-able for a reasonable DIY person. The computer diagnosis and battery report can be done with an ODBC2 adapter and relevant software (often available on smartphones). And with the web chock full of videos etc, it isn’t difficult for the interested (and careful) amateur to find out how to do some service work (though I would never trust my own life to my own inspection of the brakes).

Meatyfool..