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Hymer MLi580 Air Suspension Help Please


datadezign

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Hymer MLi580 Air Suspension Help Please

 

Hi Everyone,

 

Can anyone please help?

 

I have a Hymer MLi580 which is on a Mercedes Sprinter 316 CDi (Year 2014).

 

The big issue I have is, on a few occasions when there is a relatively steep incline, the rear end of the motorhome bottoms out on the road. I have also moved home recently and even the drive immediately from the roadside to the start of our driveway is much steeper than originally anticipated, so this does the same and bottoms out. The big issues is the fact that the body of the motorhome overhangs the rear axle by 2.2 Metres and with nearly 2.4 tons on the rear axle doesn't help.

 

It appears that what I really need is to have air bags fitted to the rear axle to lift the axle and hence the back end of the motorhome sufficiently to avoid this. I have looked at some options, to which most suppliers and fitters recommend the Dunlop air bag and compressor system. The only problem here is, I cannot get any certainty from anyone as to how much this will lift the rear end, which needs to be by at least 6 inches. I have an old friend that has suggested that I need possibly HGV heavy duty air bags that could lift up to 10 inches. Again I have contacted several companies, but no one can give me any certainty or guaranties that this will work.

 

Can anyone help, perhaps even someone that has already fitted an air bag system to a Hymer and can say from experience exactly how far this lifts the back end?

 

Please I realise there may be 1 or 2 obvious comments made such as why don't you change the motorhome to another model and blah blah. Reason we love the motorhome we have and does everything we need it to do and really don't want to change it. So please refrain from these jokes. Any genuine help and advise would be really appreciated.

 

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Hi DataD

I have a Hymer MLT560 also on a 2014 reg and I have had fitted air suspension to the rear axle its completely solved the long and low rear overhang and grounding issue - compressor fitted under the drivers seat and 2 airbags to raise and lower the rear - all controllable from the dash.

You can also use each airbag independently to level the rear when parked on uneven ground

I used AS Air Suspension of Warrington who completed the work in a morning, removing the bump stops and replacing with the airbags that can raise the rear of the van by about 10 inches as a maximum.

Best thing to do would be to give them a call and they can advise you 01925 740666 air suspension.co.uk

hope this is of help

Regards

Wiggy :-D

 

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Monique

I don't think your comment adds any value - do you own a Hymer MLT?

Do you have an air suspension system fitted by a British company?

I was pointing the original posted in the direction of a company that resolved for me a similar issue and yes rather than grounding at the rear the back of the van can be raised to approx 10" above the ground - I do not run on the road when traveling with the rear as high as this

Perhaps if you can't respond positively and answer yes to to my first two comments and questions above - you should keep your comments to yourself >:-)

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Wiggy,

 

I'm intrigued by the slight contradiction in your two posts:

 

Wiggy - 2019-09-02 4:15 PM

 

...and replacing with the airbags that can raise the rear of the van by about 10 inches as a maximum.

 

Wiggy - 2019-09-04 7:03 PM

 

...can be raised to approx 10" above the ground

 

So does your air suspension give you an additional 10 inches of lift (I assume measured at the rear bumper) or does it raise the rear to give you a total of 10 inches of ground clearance?

 

Keith.

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Hi DataD,

It is possible to fit air springs to your van and this would alleviate your problem. As with most things, it all depends on how much you wish to spend. Travel world are a major supplier of Hymers in the UK and are the only licensed UK supplier of Goldschmitt air suspension systems - recommended by Homer. I have full air fitted on my Murvi and am very pleased with it. It is a fit and forget system. VB Air is another system available through a network of authorised fitters. It is cheaper than Goldschmitt but I believe it requires an annual service check. You can google both systems and their suppliers will be happy to advise you. They will both cost several thousand to instal - they are not a cheap option but are effective and will also cure “soft” suspension.

Good luck

Old Salt

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Derek i do not calculate that Amount. We have a ride height at the axles. And that is the center of the axle to underside of the wheel arch. Full liquids. just standing. No further load. You can play about 2 inches whit this which is alot in chassis terms about GC- ground clearance. By tyre size an inflation of air. My garbage truck being a New Daf coming every 2 weeks has air seats and rear two axle air suspension. He can lift About 2 inches. But all drivers comment very differently about comfort. Up to 10 Tons. Bus coaches love them to save there back body. Same for a ambulance on air when transported whit a broken Leg.
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monique.hubrechts@gm - 2019-09-13 6:20 PM

 

Thank you for the compliment. Never seen a particular pair of air bellows. That lift up from ride height air pressure 6 inches. Just proof it.

 

Monique,

 

Derek said a lift of 6" at the REAR of the MH, not at the rear axle!

 

To get a lift of 6" at the rear bumper, and assuming a rear overhang of 60% of wheelbase, then you only need to lift the rear axle by 6 / 1.6 or 3.75"

 

I think this could easily be accomplished with decent air bellows!

 

Keith.

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Keithl That Hymer i think has not 60 percent overhang. It is bad explained anyway. It should be This way; If your front axle stays ground, and you lift up the rear axle you get a angle in degrees. I take now a strategical retreat of this site. And thank you all for the nice Chats for years and tears in my eyes. My partner Hans will take over.
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John’s Mercedes Sprinter-based Hymer MLi 580 motorhome is rear-wheel drive and (as shown in the video-clip link in my first posting above) fitting ‘semi-air’ to it will require removal of the rear bump-stops and replacing them with air-springs. Additionally, because John’s primary objective is to temporarily increase the motorhome’s rear ground-clearance significantly (“at least 6 inches”) an on-board compressor will be required.

 

Technical data for air-springs (air bellows/bags) are available on-line (example here)

 

https://www.rubena.eu/en/products/air-springs-power-elements/bellows-type-air-springs/

 

Assuming that a motorhome’s stance is level to begin with, once the bump-stops have been removed and been replaced by air-springs, for a given amount of ‘lift’ provided by those air-springs the consequential increase in rear ground clearance will vary according to the length of the motorhome’s wheelbase and the length of its rear overhang. For a given ‘lift’, the higher the percentage length of the rear overhang compared to the wheelbase, the greater the rear ground clearance increase will be. (Short wheelbase & long overhang = large rear ground clearance increase: long wheelbase & short overhang = small rear ground clearance increase).

 

While it should not be too difficult to identify for John’s Hymer the technical characteristics of air-springs that should be able to easily provide the amount of increased rear ground clearance he wants, the stumbling block is that ‘semi air’ is normally installed as a kit of parts, and the kit’s primary purpose is not to be able to increase rear ground clearance by a definite minimum but to provide “enhancements in terms of the stability, the fatigue life of the vehicle and the comfort of the passengers” and/or to allow the motorhome’s ‘chassis weight’ to be upgraded.

 

This link

 

https://www.rhinoinstalls.co.uk/VB-SemiAir-Mercedes-Sprinter-2XX-3XX-2006-onwards

 

relates to a VB semi-air suspension kit for a Mercedes Sprinter, and a price of £1150 includes a compressor and installation.

 

If the space between John’s Hymer’s rear axle and chassis were measured and the combined length of the air-spring + its mounts were established to occupy that space, it should be possible to identify how much ’spare’ extension the air-spring in a kit will have when it is fully pressurised and the effect on the rear ground clearance that extension will have.

 

The likelihood is that semi-air kits for a Sprinter will all use ‘2 corrugations’ air-springs, but the dimensions/capability of those air-springs may well vary. If a 10”-diameter spring is used, it will probably have more ‘extension’ than an 8”-diameter spring and, as temporarily maximising rear ground clearance is the requirement, opting for the kit with 10”-diameter air-springs would be the better choice.

 

The trouble is that, although it should be practicable to identify an air-spring that could definitely provide a rear ground clearance increase of well over 6”, there might not be enough space to fit that spring above the rear axle or - more inhibiting - no kit is marketed that includes that air-spring. So it’s perhaps not too surprising that companies that offer ’semi air’ are not prepared to guarantee (sight unseen) that what they can provide can increase John’s Hymer’s rear ground clearance by 6 inches.

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monique.hubrechts@gm - 2019-09-14 4:04 AM

 

That Hymer i think has not 60 percent overhang. It is bad explained anyway. It should be This way; If your front axle stays ground, and you lift up the rear axle you get a angle in degrees. I take now a strategical retreat of this site. And thank you all for the nice Chats for years and tears in my eyes. My partner Hans will take over.

 

Monique, I hope you are not withdrawing on account of some ill judged, pompous barbs from one individual?

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I agree with the above post, the comments were unacceptable, and I am surprised the moderator did not take some action.

There was I belive a misunderstanding regarding lift at the axle and that at the extreme rear. Even so I very much doubt that an increase in lift of 10 inches could be achieved at the rear.

One factor that seems to have been overlooked is that with an auxiliary air system the lift at the axle is limited by the shock absorber maximum extension regardless of the air bag properties .

 

Mike

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If you mean me, just say so - I don’t hide behind a weird nom-de-plume - and I meant my comment literally.

 

Take a large piece of ‘fine scale’ graph paper and draw a horizontal line on it to represent the distance from the Hymer’s front-axle centre-line to the motorhome’s rear. Mark on that line where the rear-axle’s centre-line occurs. Now draw a line fom the front-axle centre-line point, with that line angling upwards so that it passes 6” above the original ‘motorhome rear’ point. It should then be possible to get an idea of how much ‘lift’ would be required at the rear-axle centre-line point to obtain the required 6” ground-clearance increase.

 

This a crude geometric approach and, when I was 14 and studying maths in school 61 years ago, I’m certain would have presented no great challenge. I suspect that it should be practicable to establish a more accurate value for the ‘lift’ (using the Pythagorean theorem perhaps) as - as I said in my first posting - the Hymer’s wheelbase and rear overhang lengths will be known factors (as will the current rear ground clearance).

 

John said "The only problem here is, I cannot get any certainty from anyone as to how much this will lift the rear end, which needs to be by at least 6 inches”. So it’s plain that he’s looking for a ground-clearance increase of 6” and not an increase of 10”. As mikefitz warns, ‘lift’ at the rear axle will potentially be constrained by the damper unit’s maximum extension, but - given that the length of the Hymer’s rear overhang is 2.2 metres - a relatively small amount of ‘lift’ (say 3” to 4”) should produce a substantial increase in rear-end ground clearance.

 

(As I’m a forum Moderator I’ve edited my earlier posting to remove the text that found disfavour.)

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Don't forget the max travel of the rear shock absorbers may limit what you can accomplish. I've just let all the air out of my semi air bags then pumped them up to 3 bar lift was 95 mm at the axle 130 mm at the back of the van. Elddis Aspire 255 2012. if that gives you a clue.
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That’s what mikefitz warned about above as a potential limiting factor.

 

However your FWD Peugeot Boxer-based Elddis Aspire 255 is a very different beast to John’s 2014 RWD Mercedes Sprinter-based Hymer MLi 580, and there’s definitely no certainty that the values you’ve quoted for the sem-air system fitted to your motorhome would translate similarly to a semi-kit suitable for John’s Hymer.

 

In his posting of 7 September 2019 10:39 AM above David (davidmac) mentions that the semi-air system fitted to his Auto-Sleeper Luxor could increase its rear ground clearance by about 120mm - but the Luxor was also FWD Peugeot-based not RWD Mercedes-based.

 

John wants at least a 6" (c.150mm) rear ground clearance increase. But if no supplier of a semi-air system suitable for John’s Hymer can guarantee that this increase can be attained, it may be necessary to choose a kit from a specialist with a good reputation (eg. VB-Airsuspension), check that the kit has ‘meaty’ air-springs (and whether more than one air-spring design is available) and hope that the chosen kit will provide a sufficiently large ground clearance increase.

 

While it would be nice to be certain before committing to having a particular kit installed, it sounds like John will be forced to have a kit fitted to stop the Hymer’s rear end grounding on his home’s driveway and on other steep inclines. Even if the maximum increase proved to be 5” not 6”, that should still be worthwhile.

 

'Skid wheels’ are available to minimise potential grounding damage (discussed here)

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Scraping-my-Bottom-/24518/

 

but semi-air is a much better approach.

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mikefitz is that personal to me? Every 14 year school Kid understand that the axle lift is limied by the front and rear shock absorbers. Pythagoras. What you do not have is that in case of air suspension on the rear you have a completily different shock absorber. Alko has it in detail what happens in your wheel arch. But i leave. Its up to others Now.
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In John’s original posting he said

 

Can anyone help, perhaps even someone that has already fitted an air bag system to a Hymer and can say from experience exactly how far this lifts the back end?

 

This is a perfectly understandable request. However, although it should be possible to establish with a high degree of confidence whether the 6” increase in rear ground clearance John is looking for can be attained by fitting a 'semi-air' system to his Hymer and, if that increase proves to be a practical proposition, whether a specific semi-air kit can probably provide the increase, the exercise will take some effort.

 

As John says, what he really needs is feedback from someone who owns (or has owned) a similar-age Hymer MLi 580 with a retrofitted semi-air system and can tell him how much extra ground clearance that system is/was able to produce. Failing that, if there’s no Hymer MLi 580 owner who can comment, whether there’s anyone with a similar specification Mercedes Sprinter-based motorhome who can advise.

 

In this thread’s 2nd posting “Wiggy” said that he owned a Sprinter-based Hymer MLT 560 that had been retrofitted with a semi-air system by this company

 

https://www.as-airsuspension.co.uk/#

 

and this had successfully addressed grounding issues created by the motorhome’s long rear overhang.

 

Although the MLT 560 differs in design (low profile rather than A-class) from the MLi 580, it will have been built on a similar Mercedes chassis, is a similar length and is likely to have similar potential grounding problems.

 

There was argument (never resolved) over how much extra ground clearance the system fitted to Wiggy’s motorhome could provide, but if it can lift the rear end by 10”, that well exceeds John’s requirement for a temporary lift of at least 6”.

 

There are Hymer and Sprinter-related forums where John might seek advice, but it might be best for John and Wiggy to discuss the matter directly via this forum’s PM feature, where Wiggy could provide technical information about the system he has.

 

In these 2015/2016 forum threads

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Air-Suspension-on-Hymer-MLT/40333/

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Alko-Chassis-v-2016-HYMER-Mercedes-Chassis-/45640/

 

Wiggy mentions the rear grounding issues he had with his Hymer motorhome and (in the 2nd link) that the cost of the semi-air system fitted to his vehicle was £1000.

 

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Derek Uzzell - 2019-09-15 8:36 AM

 

In John’s original posting he said

 

Can anyone help, perhaps even someone that has already fitted an air bag system to a Hymer and can say from experience exactly how far this lifts the back end?

 

 

And seen as John has not logged onto the forum since the 2nd of September I think he may have either found the answer elsewhere or got bored with all the to'ing and fro'ing on here and lost interest!!!

 

Unless John comes back asking for more help I think this thread is best left to slide down the page.

 

Keith.

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errr... no you were never in the picture. Suggest you read back through Newbie comments. Given that, I note your intensely personal comment about weird "non de plumes". Actually you have no clue why someone might choose such a route from a security angle. I can make similar assumptions and conclude and assume you are in pyjamas in your basement deleting unfavoured comments. 2 way street.
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