Air Suspension LIFT Back End 6ins+ for Hymer MLi580-Mercedes Sprinter

[datadezign]

Air Suspension LIFT Back End 6ins+ for Hymer MLi580-Mercedes Sprinter

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 axil by 2.2 Metres and with nearly 2.4 tons on the rear axil doesn't help.

It appears that what I really need is to have air bags fitted to the rear axil to lift the axil 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.

 

[DavidG58]

We fitted VB air to our Hymer for exactly the reason you mention, don’t actually know the lift but provided I remember to use it I don’t ground anymore ?

But £5K investment

 

[tonyidle]

Air assist in my limited experience can increase the gap between the axle and the chassis by approx 2". From this you can calculate lift at the tail.

 

[Hagstrom]

We have a 2010 Frankia 8.4metre 518CDI Sprinter-based van with a long overhang on the rear axle. By my reckoning, our Dunlop(?) rear air bags raise the back end by around 1 and 3/4 inches, only, measured at the rear bumper/apron. (We pump up the bags to 2.5bar but you could take them to, perhaps, 4bar.)
I had the same problem of grounding accessing our home driveway and removing the towbar gave us the best outcome, as it was hitting the ground first. Since it's gone we have no problems grounding anywhere eg, driveway, ferries, campsites.

 

[datadezign]

Thank you all for your replies:

Air assist in my limited experience can increase the gap between the axle and the chassis by approx 2". From this you can calculate lift at the tail.

Tony you mentioned the above, could to please advise, if this lifts the axil by nearly 2 inches how would I calculate what the actual lift at the back of the van would be? This had been suggested to me before by someone that could fit one, but I assume they couldn't calculate this as couldn't tel me?

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[datadezign]

Hagstrom, do you know by how much yours lifted this at the rear end?

Which system did you guys use, was this the Dunlop one or an alternative one?

 

[MikeD]

We have a rear air assist - Dunlop system fitted by Dave Newell.

There are a couple of photo's in my media (page 3) that show the difference between 1 bar and 6 bar of pressure.

Its only around 1" difference.

But remember it would probably lift the back end of the motorhome anyway just be fitting it.

Whether you get 6" lift would be debatable.

 

[joka250]

Thank you all for your replies:

Air assist in my limited experience can increase the gap between the axle and the chassis by approx 2". From this you can calculate lift at the tail.

Tony you mentioned the above, could to please advise, if this lifts the axil by nearly 2 inches how would I calculate what the actual lift at the back of the van would be? This had been suggested to me before by someone that could fit one, but I assume they couldn't calculate this as couldn't tel me?

Little bit of geometry to create a scale drawing will give a fairly accurate answer.

 

[tacr2man]

Airsprings will lift the rear axle , but they are designed to provide a compliant suspension as well . The diameter usually dictates to a fair degree how much lift you can achieve , and has to be offset by the amount of room you (travel) you have available . In some cases it requires multi chamber air springs to achieve satisfying the constraints . You may need to go to a dedicated lift system , rather than one that can be used as a suspension aid . Having a look on this site may be of help https://www.firestoneip.com/ They also have a contact help section . You may also not need that much lift on axle line to get a considerable lift on rear end . as suggested bit of geometry might give you a answer

 

[datadezign]

Thank you Joka, perhaps I should have studied harder at school as not quite to sure how to go about this, perhaps that's also why a supplier and installer cannot answer my questions. Can you give a detailed explanation on how you would calculate this? The end of the Hymer van overhangs the centre of the rear axil by 2.2 metres?

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[tonyidle]

Thank you all for your replies:

Air assist in my limited experience can increase the gap between the axle and the chassis by approx 2". From this you can calculate lift at the tail.

Tony you mentioned the above, could to please advise, if this lifts the axil by nearly 2 inches how would I calculate what the actual lift at the back of the van would be? This had been suggested to me before by someone that could fit one, but I assume they couldn't calculate this as couldn't tel me?

As suggested a simple drawing to scale. Draw a line representing the wheelbase then extend it by the length of your overhang. Mark a point on the line representing the rear axle the mark a point 2" (same scale as your line) above it. Draw a line from the front axle, through the mark you made, to end at the end of the overhang. The height of the new line above the original at the end of the overhang is the lift you'll gain.

 

[datadezign]

Hi tacr2man,

Could you kindly elaborate?

I understand the main benefit of air suspension as have already spoken to SV tech. The Hymer motorhome had an increase fully laden weight as a factory fitted option, to which I have been told they did all the necessary adjustments including heavier duty tyres to support this increase. As said before my main objective is to be able to lift the rear end significantly to give sufficient clearance to avoid bottoming out. The additional weight support and ride comfort to me is just a bonus.

Does anyone know specifically what type of air suspension make / model no. and or combined with other methods that could potentially lift my Hymer rear end by up to 6 inches or more, any any calculations using geometry if needed to calculate this, and names of a supplier and installer that could confidently advise me without doubt?

 

[datadezign]

Hi Tony,

thank you that is very helpful, could I trouble you for a diagram that shows this?

 

[datadezign]

Hi Tony,

So the drawing shows a line drawn from the front axil to the point 2 inches above the rear axil and then the line continues by the overhang length - is that right? That's sound right to me as the incline in height from the front to the rear then continues to increase as it reaches the end of the overhang??

 

[TheBig1]

with an air assist bag system, you will seriously struggle to attain 150mm (6 inches) at the rear bumper. however a pair of uprated leaf springs with an extra leaf would work though

Jones Springs, Walsall make them

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[datadezign]

The scaled drawing appear to achieve an extra 2 inches lift giving a total lift of around 4 inches, but of course not 6 which is the minimum I would ideally like to achieve. You have suggested a pair of uprated leaf springs that may work. Can you suggest a supplier and installer that may be able to do this work for me? As said in my previous messages that, I have not yet spoken to anyone that give me a definitive solution for my problem. I appreciate they can't be exact, but as you have suggested, if they said by adding uprated leaf springs and adding this particular air bags we can get reasonably close to what you need to achieve. Wherever you go, there are so many people that are non committal.

 

[Hagstrom]

The 1 and 3/4inches lift I get is measured at the bottom of the rear apron and the ground clearance at that spot. The 1 and 3/4 inches is the difference between the bags deflated and inflated to maximum lift. (The bags sure do improve the ride, especially going around roundabouts and in high winds.)

 

[datadezign]

Thank you Hagstrom.

 

[Hettie's Crew]

Maybe you could send your photos and a description with measurements to Phil at AS Suspension. He may be able to help.

AS Air Suspension

AS Air Suspension UK Ltd. The No1 Air Suspension for all vehicles, ALKO & Non ALKO chasis. If you're not happy with the ride of your motorhome or you keep grounding at the rear then air suspension is what you need, Just read our testimonials. It will make your motorhome feel like a new vehicle!

www.as-airsuspension.co.uk

 

[TheBig1]

You have suggested a pair of uprated leaf springs that may work. Can you suggest a supplier and installer that may be able to do this work for me?

As I posted, Jones Springs in walsall www.jones-springs.co.uk

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[TheBig1]

You have suggested a pair of uprated leaf springs that may work. Can you suggest a supplier and installer that may be able to do this work for me?

As I posted, Jones Springs in walsall www.jones-springs.co.uk

 

[datadezign]

Hi Liz and Tim,

Many thanks for that, I have just called Kath Phil's wife, she was extremely helpful and very knowledgeable. She said that it was highly unlikely we would achieve 6 inch lift but would guarantee 3 inches at the axil which may increase more at the far end of the motorhome. It is strange that someone else I contacted could not guarantee any lift increase although it was suggested it may lift it up to 2 inches. Perhaps it depends on the brand of air bag. One was Dunlop and the other AS air bags made in Holland, although it was sugested Dunlop make most of the air bags on the market. Confused

 

[datadezign]

thank you I called them yes they do the springs, but was hoping for a company that can do both rather than one having to rely on the other, but yes its an option.

 

[Hettie's Crew]

I have just called Kath Phil's wife, she was extremely helpful and very knowledgeable.

Can’t recommend them highly enough, they did our air assist on our Alko chassis Hymer, so good was their service that we went back and had HPC levellers.

 

[datadezign]

I had booked for Dave Newell to do them, but as said further back in my thread that concerned can't guarantee a 2 inch lift whereas Kath could guarantee a 3 inch lift which almost certainly will lift this more at the far rear.

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[Theonlysue]

The earlier mli were low at the back and would possibly hit the road.
I spoke to sap at Doncaster, and was there when he phoned Mercedes.
Mercedes said there was not enough room for just rear air ride. It would fit but might start leaking after 9 months to a year, so with my chassis number, Mercedes recommended all round air ride.
The more modern mli have raised the rear to improve ground clearance.

 

[datadezign]

So air LIFT as suggested is a better option that air RIDE so are these two different systems, and if so is there a supplier and installer anyone can recommend?

 

[TheBig1]

So air LIFT as suggested is a better option that air RIDE so are these two different systems, and if so is there a supplier and installer anyone can recommend?

air ride is a business name synonymous with air assisted suspension. like hoover is to vacuum cleaners

full air is a full suspension replacement but massively expensive

what you need is new springs installed by a fabricator who can fabricate longer hangers at the same time to give the required lift. or new springs and replace the bump stops with air assist bags to be adjustable

 

[Speve]

datadezign .We have Goldschmidt full air on our Hymer here’s what is in their publicity pdf.

The advantages of the Goldschmitt system
• Considerably more driving comfort
• More driving safety
• Loading errors are balanced out by the automatic levelling device
• Uprating option depending on chassis up to 4.5 t
• Wear-free valves
• Unique mounting on the chassis
- Wheel guided with little noise and no play
- No change to axle geometry
• Maintenance-free and self-regenerating air dryer (no icing-up)
• Up to 160 mm spring travel
• Four programmable ride height
• Can be retrofitted on most models
• Developed in Germany

Hope it’s useful not cheap though???

 

[Landy Andy]

I don’t think anyone will be able to give you definite answers, as it will depend on your setup/weights/design of vehicle. Fitting rear semi air on mine lifts the tow bar about 3”, but it wasn’t low to start with. So if my vehicle was heavier it would have sat lower before fitting the semi air, and now I would be telling you it raised it 4-5-6”.

If that makes any sense.

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