While looking something else up on the MoT testers manual, I came across this section

5.3.5. Gas, air and fluid suspension

Defect Category

(a) A gas, air or fluid suspension system inoperative - Dangerous

(b) A gas, air or fluid suspension system component damaged, modified or deteriorated in a way that:
(i) it would adversely affect the functioning of the system - Major
(ii) its function is seriously affected - Dangerous

(c) An obvious leak from any part of the system - Major

That suggests to me that a P38 on coil springs should be an automatic fail under 5.3.5 (b)(i)

Unless if it has been removed then it cannot be malfunctioning, and 5.3.5 does not apply.

th.

Surely under (b) the suspension system has been modified? That is how I would read it anyway.

Section b seems to be referring to "components" that may have been modified.
If the whole suspension has been changed, it would not apply.
(Oh my, what if you modify a spring!?)

Now, not ever having spent a quiet evening perusing the MOT testers manual......
What's it have to say about "modified vehicles"
Surely changing the whole design of the suspension would qualify as a modification? "Got a permit for those springs chum?"
Heck, there's probably a detector van out looking for just that!!

I reckon 5.3.5 doesn't apply if it isn't presented with air suspension, so you never get as far as reading 5.3.5 b

Though that may beg the question what would happen if the air suspension were removed and it were presented with solid bars instead of springs (so springs would also not apply)? But even if there were nothing prescribed for that situation common sense should prevail?

Bolt wrote:

Section b seems to be referring to "components" that may have been modified.
If the whole suspension has been changed, it would not apply.
(Oh my, what if you modify a spring!?)

I think you are probably right as the whole system has been changed, so it is the vehicle that has been modified, rather than an individual component. I've seen a car (not a P38) that had had the suspension lowered by clamping the springs and heating them up with a welding torch. That, I would assume, would be noticed by the tester (I noticed it as soon as I looked under the car) and frowned upon but if whoever did it had simply cut one turn off the coil, as long as it remained in place when the suspension was fully extended, it would be no different to fitting a shorter spring.

What's it have to say about "modified vehicles"
Surely changing the whole design of the suspension would qualify as a modification?

There's only the odd mention of modified vehicles, for instance, if a car has been fitted with an engine older than the car, the emissions limits are those that apply to the engine as limits have been tightened over the years. So if I was to ever achieve one of my fantasies of fitting a P38 V8 into a Prius, the emissions limits would be for the P38 engine, not those that would apply to the Prius. Most modifications are allowed here as long as items still work as expected. I know of one car that is virtually all hand built using a pair of 6 cylinder Jaguar XK engines in tandem so it is an 8 litre straight 12. That was built on the chassis from an old FX taxi (the traditional London black cab) and, as it retained the chassis and suspension from the original vehicle, it is regarded as the same car.

The only reason I was looking was because I wanted clarification on whether a spit ball joint boot on my other half's Merc would be a fail or advisory. Seems that a boot that is deteriorated but still keeps dirt out of the ball joint is an advisory but if it is split and would allow dirt in, it's a fail. Which is a real bugger as I've got to change a track control arm and re-align the steering because the boot is split and not because there is any wear in the ball joint......

Richard: Don't know the details on your Merc but I have used the old approach, basically as used on Bailcast CV split joints but with ball joints, to the satisfaction of MOT testers anyway: I use an 'oversized' (for the car/jpoint) ball joint boot split (cut) and overlapped/glued up in order to prevent the famous "water/dirt ingress" fail problem.
Split boots held in place at both ends with stainless clips of course...... and, if done properly, it stays good for years too.

PS: While you have the MOT Testers book handy what does it say (indicate) about chassis corrosion on P38s ?
I ask as I had this 'gem' for mine last year:

"significant amount of rust and corrosion on under chassis not affecting suspension points or load bearing joints but needs attention"

It was from a very pedantic MOT Tester, who probably does not see many chassis-based 30-year-old cars ?
There was a 'discussion' that followed -mainly about chassis vs monocoque construction - and the EAS too...!.
Corrosion on a P38; Who knew ??

As I read that if you presented a P38 for an MOT when it was on the bump stops that it would be a "Dangerous" fail & you wouldn't be allowed to drive away from the testing station.

davew wrote:

PS: While you have the MOT Testers book handy what does it say (indicate) about chassis corrosion on P38s ?

I don't have it handy, I just open it up if I need to check something, it's here https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles

Your note isn't a specific fault but a free text one put in by the tester because he can, so anything that doesn't have the exact section number is a pedantic tester (usually done so gullible customers will pay him to put right faults that aren't actually faults). I've seen ones like, "Sump rusty but not leaking" and? The section on the chassis is https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/6-body-structure-and-attachments and the appendix (https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/appendix-a-structural-integrity-and-corrosion) points out to thick testers what bits he should look.

nigelbb wrote:

As I read that if you presented a P38 for an MOT when it was on the bump stops that it would be a "Dangerous" fail & you wouldn't be allowed to drive away from the testing station.

I don't want to detract too much from the thread but what I meant was if bars were fitted in place of springs so it wasn't on the bump stops. In that case you don't have airbags or springs that could be broken but effectively you don't have any suspension either. An equivalent to what I meant might be fitting ultra tough inflexible tungsten or titanium springs.

I would say that would come under 5.3.1 d(ii), a Spring modified so the suspension is inoperative. See https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/5-axles-wheels-tyres-and-suspension. However, if it is a very old vehicle that never had suspension in the first place, it would still pass (even though it would no longer require an MoT these days).

Gilbertd wrote:

I would say that would come under 5.3.1 d(ii), a Spring modified so the suspension is inoperative. See https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/5-axles-wheels-tyres-and-suspension. However, if it is a very old vehicle that never had suspension in the first place, it would still pass (even though it would no longer require an MoT these days).

Thanks, yes I see that now. 5.3.1.d
(d) A spring:

(i) with an unsafe modification
(ii) modified so that the suspension is inoperative

Major
Dangerous

RE: Chassis/Corrosion/MOT:
Thanks for the links Richard: Agree that the (overly pedantic) MOT inspector's remarks effectively fall into the 'so what ?' category.....
as i asked if the 'attention needed' would involve painting underseal over it to hide it.... and/or a 'sacrifical anode' approach...(!)?
Less 'whimsical' however was my explanation that the P38 air susupension uses quite a low pressure over a large surface area
and so that is much less critical that the 'usual' suspension arrangement with more load focused on a smaller contact points...
Worth considering mentioning that (or similar) if any other members also encounter any unusually-pedantic MOT inspectors ....?