Air suspension - overnight loss of pressure.

sciac2001

Funster
Jul 18, 2010
576
641
Bournemouth and Gibraltar
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Since 2003
Had DunLop air suspension fitted professionally (by our competent local motorhome repairers) in July this year. A day after fitting I noticed a pressure loss and returned it for inspection. The repairer duly tested the system and found no air loss in the system nor a fault.
We have proceeded with our European tour but after monitoring for a few weeks, find that we are definately losing pressure every time we park up overnight. The pressure loss however is only noticed on the offside airbag as the nearside one tends to keep to the set level.
I cannot take it back to the dealer until we return in June next year so am hoping that some funster may offer some advise as to possible causes and ideally offer a low-tech fix that
I could do myself in the field.
The loss is not severe and I am able to pump up to the required level before setting off every time. I do however feel that something is amiss with the system which was far from cheap.

On a related issue, does anyone know what the correct setting for air-suspension on a motorhome with a scoooter rack carrying a 125kg motorbike and approx 40kgs of bicycles should be? I am currently setting it at 4psi. My system can be set significantly higher if required.
Many thanks
 
Feb 24, 2013
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not long enough
do you mean 4 bar? I don't think 4 psi would even show on the gauge

we possibly have a similar system and carry a 12V compressor to refill, sometimes lose lots of pressure for no obvious reason, but run ours around 60psi (y)
 
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TheBig1

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soapy water in a spray bottle. spray the soap and water onto each joint in the hose/airbag. if/where its leaking, you will see bubbles. best to put a higher pressure in the bags for testing and to help joints bed in. on some kits the joints are just push fit, and any roughness on the side of the tube can cause a leak
 
Dec 21, 2011
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We have a similar system fitted by Dave Newell. It holds its pressure pretty well and never needs re-charging.

I suspect as it is a new system you have not had any component failure and so have a leaking connection somewhere.

I run mine with just enough pressure to regain a good ride height. Probably only about 2 to 2.5 bar. We are fairly heavily laden with a Easylift - hydra trail on the tow bar with a 165kg Vespa scooter.

Hope this helps (y)
 
Apr 13, 2012
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We have a similar system fitted by Dave Newell. It holds its pressure pretty well and never needs re-charging.
I suspect as it is a new system you have not had any component failure and so have a leaking connection somewhere.
I run mine with just enough pressure to regain a good ride height. Probably only about 2 to 2.5 bar. We are fairly heavily laden with a Easylift - hydra trail on the tow bar with a 165kg Vespa scooter.
Hope this helps (y)
Never ran mine above 3 bar, often at 2bar - whatever was comfortable ....try running at a lower pressure


(y)
 
Feb 24, 2013
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not long enough
I will lower mine tomorrow, never got any guidance when we bought it and have noticed the ride on uneven ground is awful

will try 20 psi see how it goes

I picked 60 psi because the gauge went up to 100!! somewhere in middle :doh:
 
Oct 5, 2010
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autotrail chieftain se
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on our last m/h the dunlop air bags(bellows) leaked air through the rubber after 18months. I put a small amount of that anti puncture stuff in them, the green slime stuff, although mine was pink...this cured mine.
You have to put it directly in to the bag and not down the pipe work as this just blocks the pipes.
spray a soapy mix around your air bags and you'll see if they are leaking.
ps.. used to run mine at 4 bar
 

buffallobill

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Sep 21, 2013
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I fitted Dunlop air suspension 2months ago to our fiat xlwb, weight 3850kg. Had small air loss over a couple of days, so I made sure the left and right air lines where cut square and clean on the ends and then made sure the air lines where pushed all the way home into the gauge push fit fitting. Then while there was still no pressure in the system I managed to check the air lines connection between bottom of air bag and rear spring by gently turning the round knurled nut tightish to ensure a seal of the plastic air pipe, (used long nosed pliers). Then I inflated system to 80 psi.( manual States max 100psi) then reduced to 50psi which I now run at fully loaded , I still get a small pressure loss of 2 to 4 psi over the month which I find permissible . Hope you find a solution , good luck bill.
 

Tootles

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Dave fitted new air bags on our truck this year. I keep them at around 3.5 bar, but do notice a slight loss, up to 8 psi per week, when moving a lot, but no loss when parked up. I can live with that.
 

Bertie Bassett

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I will lower mine tomorrow, never got any guidance when we bought it and have noticed the ride on uneven ground is awful
will try 20 psi see how it goes
I picked 60 psi because the gauge went up to 100!! somewhere in middle :doh:
Our skills in these technical areas are identical, are we related by any chance?;)
 

Tootles

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I'll have you both know I was asked to leave the school army cadets, never thought of myself as having been put on this earth to take orders :D
Was that for pulling your willy out of your combats, jumping up and down screaming AN ELEPHANT!....SAVE ME!.;):)
 

Bertie Bassett

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I'll have you both know I was asked to leave the school army cadets, never thought of myself as having been put on this earth to take orders :D
That should be a statement accompanied by signs of great pride and much laughter.:D But I'm intrigued, what did you do, unless of course it's 'private'?:sneaky:
 

Tootles

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His unit was the 47th Spankers..........And the Major was a gay old thing.......:ROFLMAO:
 

icantremember

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We have the brilliant AS Air suspension system with a built in compressor so it can be adjusted from the driving position while on the move.

I was told at the time of fitting that the bags can be damaged if run at too low pressure, 2 bar if I recall correctly is about the minimum.
 

DuxDeluxe

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Run mine at just under 2 bar. Very good ride now and no leakage noted to date. Couldn't see the point of all the compressors etc, so just went for the cheapest option as it was something that we leave alone when the right pressure/ride height combination was found
 
Dec 21, 2011
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The Marcle web site give Dunlop installation instructions. They also state max and min pressures. (y)

Maximum and Minimum Pressure

Maximum Pressure 7.0bar Minimum Pressure 0.5bar

Do not exceed 7.0bar (101psi), which is the recommended maximum charge pressure for the air springs.

The springs may be deflated if the vehicle is to be stored for a lengthy period without use, but a pressure of at least 0.5bar (7.25psi) should be maintained at all times in order to avoid possible compression damage to the springs.

http://www.marcle-leisure.co.uk/information/dunlop-instructions-06.htm

We have rear assist only but also use the air suspension to level the van if required on site, left to right and back to front.

Also whilst not aimed at motorhomes some parts of PM85 are relevent and worth reading. Especially regarding crushing.

http://www.hse.gov.uk/pubns/pm85.pdf
 
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OP
sciac2001

sciac2001

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Thank you all.
Received a note from the uk distributors that the problem might be a leaky non-return valve By the compressor. Sent me instructions on how to fix.
(It does want me to lower the pressure to the absolute minimum - 0. A tad uncomfortable with that as I was told NEVER to have it lower than 2.
Mmmmmm!
 

funflair

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Thank you all.
Received a note from the uk distributors that the problem might be a leaky non-return valve By the compressor. Sent me instructions on how to fix.
(It does want me to lower the pressure to the absolute minimum - 0. A tad uncomfortable with that as I was told NEVER to have it lower than 2.
Mmmmmm!
That will be just to work on it I imagine, I would not drive around like that but just whilst stationary should be OK, it's just to stop the bag getting nipped, if you were really bothered you could put a couple of jacks under the chassis to stop it coming all the way down when you let the air out.
 
OP
sciac2001

sciac2001

Funster
Jul 18, 2010
576
641
Bournemouth and Gibraltar
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Thanks again. I am a little puzzled though... if i did have an airleak, why does the pressure tend to stabilise at 3bar? It just loses abiut 1 bar from a setting of 4bar and then stabilise....
 

Badknee

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Aug 25, 2014
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4bar opens the leak, stops leaking at 3bar.
 
OP
sciac2001

sciac2001

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Sorry, not quite with you. Do you mean that any air leak will stop at 3bar?
(I assume that there would be a reason for this?)
 

Badknee

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Sorry, not quite with you. Do you mean that any air leak will stop at 3bar?
(I assume that there would be a reason for this?)
No, say at 3bar all is well but not totally happy. You come along and blow it up to 4bar and something opens up and leaks air. When leak gets down to 3bar the fitting/bag can cope and stops leaking.
 
Dec 21, 2011
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Thanks but would'nt both airbaga be similarly affected?

On my air suspension the left and right air bags/lines are on separate valves so each are independent of each other. A leak on one side would not affect the other.

We have an onboard air compressor and use the air suspension to level the van both crossways and lengthways.
 
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