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MOT fail - rear transit suspension


Mr Motorhome

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Hi All

 

My 2007 Hymer 682 CL on a Ford Transit base (28,000 miles) has recently failed its MOT on the rear suspension due to inadequate clearance/riding on the bump stops. The single leaf springs were replaced with heavy duty twin leaf springs along with an up-rate spring incurring quite an expense!

 

However, it seems that the so called ‘bump stops’ may well in fact be ‘spring assisters’ and are actually part of the suspension system and it’s not uncommon for there to be no clearance so shouldn’t be a cause of an MOT failure. I found a post on the forums from 2010 about the same issue but don’t know what the outcome was

 

I’m now wondering if this extra work and expense was actually necessary. My other concern is the extra weight of these heavy duty springs eating into my available payload.

 

I would be interested in hearing other people’s views regarding this and especially from anyone who may have had a similar experience.

 

Regards,

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This will be the 2010 forum thread that you mention in your original posting

 

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Hints-and-Tips/Ford-suspension/19542/

 

This potential problem at MOT time was discussed in considerable depth in the 2010 forum thread. Nothing has really changed since then, so I‘m not sure what additional advice can be provided now.

 

It’s possible (I suppose) that your Hymer’s single-leaf rear springs will have deteriorated after 10 years and that replacing them with twin-leaf springs will be beneficial. This possibility could have been explored before the springs were replaced (eg. by removing the ‘bump-stops’ and seeing if the motorhome’s rear end sagged significantly) but it’s too late for that now.

 

My FWD Transit-based 2005 Hobby T-600FC motorhome had the long bump-stops but the springs were twin-leaf - and the bump-stops still touched the rear axle in normal use. The Hobby was a good bit smaller and lighter than your Hymer and the rear suspension was fairly firm, so you may find that the new stronger springs improve your motorhome’s handling.

 

The following two 2011 forum threads

 

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Ducato-X250-failed-rear-leaf-springs/23404/

 

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Ducato-X250-rear-leaf-springs-MOT-issues/23529/

 

relate to a similar situation where a Fiat Ducato-based Adria motorhome had its rear springs replaced after failing an MOT test due to its ‘bump-stops’ having no clearance. Eventually it was admitted that an error had been made and the cost of the replacement springs was refunded, but a lot of effort was needed to achieve thst result.

 

As pelmetman as suggested, replacing the bump-stops with air-bellows units side-steps the possibility that an MOT tester will fail the vehicle due to lack of bump-stop clearance. But that’s easy to say with the benefit of hindsight and, of course, assumes that the motorhome owner will be aware of the bump-stop-failure possibility and has air-bellows fitted prior to the test being carried out, or insists that air-bellows be fitted instead of replacement springs.

 

You haven’t said how much the new springs cost, but nowadays the price of an air-bellows kit for a 2007 FWD Transit Mk 7 is likely to be £350-£450 (plus fitting).

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As Derek says (or at least infers) trying to analyse the problem at this stage is not practical, yes in past some have had problems with MOT inspectors not understanding how spring assistors work, but it would be odd that this is still a problem for any centre that does vans. Looking at your van it may well be that the rear is heavily loaded and sits low, and it would not be surprising to find it sagging over time.
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colin - 2018-03-16 9:10 AM

 

As Derek says (or at least infers) trying to analyse the problem at this stage is not practical, yes in past some have had problems with MOT inspectors not understanding how spring assistors work, but it would be odd that this is still a problem for any centre that does vans. Looking at your van it may well be that the rear is heavily loaded and sits low, and it would not be surprising to find it sagging over time.

 

I wouldn't be so confident in the knowledge of MOT testers. A similar fail happened to a Ducato owner on another forum fairly recently. An MOT tester and motorhome owner on that forum also posted confirming his opinion that it was a fail and that he would also have failed the vehicle.

 

Only after being referred to the Matters of Testing article and a copy of Fiat's own technical document confirming that the Ducato "bump stops" are in fact suspension assisters did he change his view.

 

The Fiat document will not help with a Transit, but the Matters of Testing article that all MOT testers should have received and read is linked here:

 

https://mattersoftesting.blog.gov.uk/the-knowledge-spring-assisters-and-bump-stops/

 

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Yes the bump stops of fiat ducato leaf springs are part of the suspension. In case of a alko torsion bar axle it it is the torsion max load of the bars relating to the maxload of the axle, as the leaf sprigs are. But still you a shock absorber which should be in line. The tyres working like air suspension do not form a part of the suspension at the MOT.
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Just braved the snow to look at my 2008 transit based Hymer Exsis i and the 'bump stops' are sitting on the axle beam. I've not had and mot issue. They are obviously not bump stops but assistors. Suggest you contact the mot station and inform them that their are assistors not stops and it should not have been a fail.
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This potential problem at MOT-test time should disappear after 19 May 2018.

 

The relevant MOT inspection manuals can be viewed here

 

https://www.gov.uk/government/publications/mot-inspection-manual-for-class-3-4-5-and-7-vehicles

 

The manual currently in force has advice relating to ‘bump stops’ on Section 2.4 Page 1 (Suspension - General).

 

The manual that will be operative from 20 May 2018 has suspension-related advice in Section 5 (Axles, wheels, tyres and suspension) but ‘bump stops’ are no longer mentioned.

 

(Although the on-line 20 May-onwards manual is in draft form, there’s no reason to expect it to alter much before May.)

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If it helps, attached is a picture of the standard spring assister fitted to our 2007 Mk7 FWD Transit rear axle, taken in 2009, shortly before I substituted air assistance bellows. As you will see, that assister is in contact with the bearing plate attached to the axle for that purpose.

 

The van (Hobby Van) was unladen at the time the picture was taken. I had to jack up the chassis in order to gain enough clearance between spring assister and bearing plate in order to remove (by foot!) the spring assister, before I could fit the air assistance bellows in its place.

 

The van was serviced by a local Ford commercial dealership, and the relationship between the assister and the rear axle was never queried during services. We had the van for just over 6 years, but it was never MoT tested with its unmodified rear suspension in place.

 

Your picture is, of course, of the "after" condition of the rear suspension. Do you have the corresponding "before" picture? I note that you say the "fail" was due to "inadequate clearance/riding on the bump stops". From your picture, it still is. I assume it has been re-tested and passed? So, apart from the work you had carried out, I have to ask: what changed? As your van has only covered 28,000 miles in 11 years, it seems a little improbable that the rear spring would have settled that much in that time - unless grossly overloaded.

 

I do just wonder if the MoT, subsequent suspension modifications, and re-test were all carried out by the same garage, and particularly whether that garage was a Ford commercial dealership. If they were, I suspect you have a good case for asking for all your money back, and if a Ford commercial dealership, may additionally be able to lodge a complaint against the garage with Ford. If they were not, your work appears to have been due to an incompetent independent MoT tester incorrectly failing your van. You'd need to speak to Citizens Advice or Trading Standards to find out where you stand vis a vis recovery of your costs on that score.

 

On present evidence, it seems you may have been subjected to completely unnecessary expense, possibly due to incompetence on the part of the tester, possibly knowingly. If all that work was undertaken by a Ford commercial dealership against your quoted reason for an MoT fail (irrespective of who did the test), it is very difficult to understand why they did so, because they should have known that the relationship between spring assister and axle as in your photograph conforms with the design intent, and should have advised you accordingly.

 

I would also add that I think rear air assistance would have been a better and cheaper remedy to the problem than fitting a heavy duty double leaf spring, the likely effect of which will be a harsher ride.

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Thanks everyone for your replies, links and advice. Much appreciated.

 

The workshop that carried out the MOT is a NCC Approved workshop for Caravans and Motorhomes but not a Ford dealership. It is also who carried out the fitting of the replacement springs and the retest which it passed. The MH has done just over 100 miles since the previous MOT which it passed with no mention of any issues with regard to the suspension etc.

 

Unfortunately I don’t have any ‘before’ pictures although I had a pre-purchase inspection carried out before I bought it (approx 2 years ago) so I may have some images from that stored on my PC and again, no mention of any suspension related issues.

 

The exact wording on the MOT failure sheet is as follows: ‘inadequate clearance with the bump stop rear (rear suspension weak riding on bump stops) 2.4.A.1a’. It doesn’t specifically mention the leaf springs but I suppose ‘rear suspension weak’ covers everything!

 

As Brian mentions, if it was failed due to inadequate clearance then nothing seems to have changed after the fitting of the heavy duty springs. I was later advised that following the fitting of the springs, this hadn’t increased the clearance so they also fitted extra up-rate leaves and a subsequent pass MOT certificate was issued. This cost over £750.

 

My other concern is that the extra weight of these springs will no doubt eat into my payload. I’ll need to take it to my local weigh-bridge to check. The rear of the MH is also seems to be sitting higher than it was. Before the replacement springs were fitted I hadn’t noticed the rear of the MH ‘sagging’ or any fouling of the bodywork/tyres. I’m wondering if this will negatively affect the handling or transfer more weight onto the front axle especially under braking?

 

I have telephoned and emailed DVSA and my local Ford commercial/Transit vehicle dealership who carry out their own MOT’s. A Ford workshop manager confirmed they are suspension spring assisters and that they wouldn’t have failed it because of inadequate clearance. I’m still waiting to hear back from DVSA.

 

I don’t believe the workshop was being underhand in any way, I just feel they have mistaken the spring assisters as bump stops resulting in a fail and the subsequent expense of fitting replacement leaf springs.

 

Regards,

 

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Weighting the rear axle esp with the load it went for MOT and comparing that with the max allowed load might give an indication of any problem with overloading the rear axle. It is possible that the spring assistors where heavily compressed due to the spring sagging or being overloaded.

You would expect a workshop familiar with motorhomes to have seen many vans with no gap under the spring assistors.

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But, as you will see from other posts on this issue, there is no problem with the spring assisters being in contact with the axle: they are not bump stops. This is as the suspension was designed to operate: your Ford dealer has confirmed that. If the tester had found that the rear springs were weakened and no longer safe to rely upon, that would have been an adequate ground for failing the van. However, he did not fail it on that ground, and the ground on which he did fail it is invalid and demonstrates an inadequate understanding of this type of suspension.

 

You now unnecessarily have a non-standard rear suspension, that additionally has been raised by fitting unnecessary spacers, to create an unnecessary gap between the spring assister and the axle. You also now have unnecessary twin leaf springs, in which the second leaf performs a similar function to the spring assister: that is to say to progressively bear part of the rear axle load as the first/single leaf becomes compressed.

 

If you know that other vans have been failed on similar grounds by the same outfit, it is probable they, too, have been persuaded to pay for unnecessary suspension modifications to rectify a non-problem. At £750 a pop, that is quite good trade from a £50 MoT. Whether this is deliberate fraud on not, it is dishonest trading. If they take on the work, you are entitled to rely on them to be competent.

 

The MoT test manual to which Derek linked states, I quote: "A suspension bump stop must not be confused with rubber/synthetic suspension spring assistors." You tester did confuse the two, and he did not fail your van on a valid ground. The fact that it was subsequently necessary to fit spring spacers (no doubt at additional cost) to generate a clearance between assister and axle is surely proof enough of that.

 

The tester didn't/doesn't properly know his job and, if he has been failing other vans on similar (false) grounds, the firm that employs him is unreasonably profiting from that.

 

I really think you should speak to the firm's MD about this, and demand that they remove the unnecessary modifications they have made, return your van to its design status, and reimburse you the cost of the modifications plus the cost of the test and re-test.

 

I also think it would be public spirited if you were to advise anyone else who you know has suffered the same fate, of your findings, and give them a chance to do likewise.

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Brian, you have no evidence of that conclusion, even if it is right. The 'inadequate clearance' failure can still be valid with spring assisters, it depends on how compressed they are. AFAIK manufacturers have a figure for a compressed assistor, go below that and it's a failure.
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colin - 2018-03-19 7:20 PM

 

... AFAIK manufacturers have a figure for a compressed assistor, go below that and it's a failure.

 

When Mr Motorhome’s Transit-based motorhome left the Hymer factory, the rear suspension ‘spring-assisters’ would have been in close proxilmity to, or touching, the rear axle.

 

I’ve owned a Hobby motorhome based on this FWD Transit platform-cab chassis and I’ve seen plenty of examples of other motorhome makes that were built on that chassis. No matter which motorhome manufacturer had built the vehicle, even when the motorhome was brand-new and completely unloaded, there was always minimal or no clearance between the top of the rear axle and the bottom of the spring assister. Obviously, when the motorhome was loaded, any original clearance would likely disappear and, if the motorhome were excessively loaded at the rear, the rear leaf springs would begin to flatten and the spring-assisters would compress significantly to share that load as Ford intended. But there’s no chance whatsoever that Ford would specify an allowable distance that the spring-assister could be compressed to and that could be measured by an MOT tester and the vehicle failed if the assisters’ compressed length were less than that defined by Ford.

 

As I said above, it’s certainly possible that a Transit’s leaf springs might have weakened over time to such an extent that - when the vehicle was presented for testing - the spring assisters would be so ‘squashed’ that a tester would know there was a leaf-spring-related problem, but that’s most unlikely to be the case here.

 

All heavier Mk 6 and Mk 7 FWD Transit panel-vans and all coachbuilt motohomes built on the platform-cab chassis (essentially a panel van with no metal bodywork behind the cab section) have these long conical spring assisters, Any Ford dealership or MOT test station that deals with Transit panel vans should be aware that these suspension components are not ‘bump stops’ as such, but there will not be that many coachbuilt motorhomes in the UK with this FWD Transit chassis and I can understand a NCC Approved workhop beng unfamiliar with the rear suspension design.

 

That doesn’t really excuse the tester though, as there is a warning in the MOT Inspection Manual that “A suspension bump stop must not be confused with rubber/synthetic suspension spring assisters” and (as far as I’m concerned) it’s bleeding obvious that the plastic ‘cones’ fitted to these Transits are "rubber/synthetic suspension spring assisters”.

 

It’s near certain that there was nothing intrinsically wrong with Mr Motorhome’s Hymer’s rear suspension and, consequently, replacing the rear springs was unnecessary. The fact that the spring replacement has elevated the Hymer’s rear end must mean that the rear springing is now a lot firmer than before, but whether the effect on road-behaviour of that change will be good or bad is anybody’s guess.

 

Me, I’d want my money back as the decision to beef up the Hymer’s rear springing was based on a dubious premise and the effect of doing it will probably harm the vehicle’s ride quality and will definitely have added extra weight.

 

Mr Motorhome has forked out over £750 that he need not have done and (if he had wished to adjust the rear suspension spring setting) the money would have been much better spent on adding an air-bellows kit.

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colin - 2018-03-19 7:20 PM

 

Brian, you have no evidence of that conclusion, even if it is right. The 'inadequate clearance' failure can still be valid with spring assisters, it depends on how compressed they are. AFAIK manufacturers have a figure for a compressed assistor, go below that and it's a failure.

But, I'm going to argue that I think I have sufficient evidence to reach that conclusion, Colin.

 

First, look back at the photo in Mr Motorhome's original post. It shows (albeit it could be a touch sharper) the original synthetic spring assisters in apparently good (if grubby) condition, after the re-springing had been completed. It seems to me to show that despite the work that was done, the assister is still in contact with the axle. If so, why was the test passed the second time, still with no visible clearance?

 

Look also at the photo I attached to my post above, which shows the rear suspension of our unladen 2007 FWD Transit, taken in 2009, so only about two years old. The spring assister is in contact with the axle (actual rear axle load, 1,500kg). That is Ford's design, not a fault.

 

Take into account that the maximum rear axle load for a 2007 FWD Transit is 2,250kg, and not the 2,000kg allowed for the "light" SEVEL chassis, and consider whether that spring assister would not have been under significant compression were the axle loaded to its permissible maximum (750kg more than in the above photo). This would be the condition in which a more conventional leaf sprung rear end might be expected to run close to its bump stops.

 

Finally, look at the reason Mr Motorhome quotes from his MoT failure notice, that the failure was due to "inadequate clearance/riding on the bump stops". Look also at the note to section 2.4 of the MoT inspection manual, as quoted above, that "A suspension bump stop must not be confused with rubber/synthetic suspension spring assistors."

 

Mr Motorhome's tester did confuse the spring assister for a bump stop, and confirmed that confusion in his reason for failure as quoted above.

 

Taking those factors together I think there is good evidence to suggest to Mr Motorhome that between his tester and his chosen garage he has been charged for a substantial sum of money for a) a defective MoT test and b) unnecessary work based on that defective test. I think it also fair to conclude that a competent garage would not have undertaken that work, because a competent garage would have known the difference between a bump stop and a spring assister, and would have queried their own tester's verdict.

 

So I'm sorry if this sounds harsh, but if a firm specialises in work to motorhomes, and claims competence in carrying out MoT tests, and competence in rebuilding rear suspensions, one has a right to expect that their work will justify their claims. For me, Mr Motorhome's garage fails that test.

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Thanks again for the further replies and information. This is very helpful.

 

Today I have received an email from DVSA advising me that they are seeking further advice from the Vehicle Testing and Roadworthiness Team. I’ll update further once I hear from them.

 

Thanks again for all the the information and advice.

 

Regards,

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Brian Kirby - 2018-03-20 3:34 PM

 

colin - 2018-03-19 7:20 PM

 

Brian, you have no evidence of that conclusion, even if it is right. The 'inadequate clearance' failure can still be valid with spring assisters, it depends on how compressed they are. AFAIK manufacturers have a figure for a compressed assistor, go below that and it's a failure.

But, I'm going to argue that I think I have sufficient evidence to reach that conclusion, Colin.

 

First, look back at the photo in Mr Motorhome's original post. It shows (albeit it could be a touch sharper) the original synthetic spring assisters in apparently good (if grubby) condition, after the re-springing had been completed. It seems to me to show that despite the work that was done, the assister is still in contact with the axle. If so, why was the test passed the second time, still with no visible clearance?

 

Look also at the photo I attached to my post above, which shows the rear suspension of our unladen 2007 FWD Transit, taken in 2009, so only about two years old. The spring assister is in contact with the axle (actual rear axle load, 1,500kg). That is Ford's design, not a fault.

 

Take into account that the maximum rear axle load for a 2007 FWD Transit is 2,250kg, and not the 2,000kg allowed for the "light" SEVEL chassis, and consider whether that spring assister would not have been under significant compression were the axle loaded to its permissible maximum (750kg more than in the above photo). This would be the condition in which a more conventional leaf sprung rear end might be expected to run close to its bump stops.

 

Finally, look at the reason Mr Motorhome quotes from his MoT failure notice, that the failure was due to "inadequate clearance/riding on the bump stops". Look also at the note to section 2.4 of the MoT inspection manual, as quoted above, that "A suspension bump stop must not be confused with rubber/synthetic suspension spring assistors."

 

Mr Motorhome's tester did confuse the spring assister for a bump stop, and confirmed that confusion in his reason for failure as quoted above.

 

Taking those factors together I think there is good evidence to suggest to Mr Motorhome that between his tester and his chosen garage he has been charged for a substantial sum of money for a) a defective MoT test and b) unnecessary work based on that defective test. I think it also fair to conclude that a competent garage would not have undertaken that work, because a competent garage would have known the difference between a bump stop and a spring assister, and would have queried their own tester's verdict.

 

So I'm sorry if this sounds harsh, but if a firm specialises in work to motorhomes, and claims competence in carrying out MoT tests, and competence in rebuilding rear suspensions, one has a right to expect that their work will justify their claims. For me, Mr Motorhome's garage fails that test.

 

So lets look at the two photo's.

They are taken at close to same height, yours is slightly higher and possibly closer, but I will asume they are close to same perspective, and for my purposes this is erring on the side of caution, I can only guess that they both have the same spring assister,.

From analyzing the photos I can see that despite having heavy duty springs Mr Motorhomes assister is compressed to around 80% of yours, this is also confirmed by the third donut up being over expanded under compression whereas yours are progressively larger, so even in it's uprated state the suspension is sitting lower, but neither of us knows what the suspension looked like before being changed except it was likely to be sitting lower.

 

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Surely because they called them Bump stops that shows they where mistaken as to what they where. If they had said that the spring assisters where overloaded because the springs where weak that would have been a different thing.
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