Air suspension - overnight loss of pressure.

Discussion in 'Tech/Mech General' started by sciac2001, Sep 25, 2014.

  1. sciac2001

    sciac2001 Funster

    Joined:
    Jul 18, 2010
    Messages:
    311
    Likes Received:
    343
    Location:
    Touring Europe long-term
    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
     
  2. DavidG58

    DavidG58 Funster

    Joined:
    Feb 24, 2013
    Messages:
    6,282
    Likes Received:
    12,118
    Location:
    Bolsover, Derbyshire
    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)
     
    Last edited: Sep 25, 2014
  3. TheBig1

    TheBig1 Funster Life Member

    Joined:
    Nov 27, 2011
    Messages:
    7,222
    Likes Received:
    9,603
    Location:
    Dorset
    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
     
    • Like Like x 3
  4. MikeD

    MikeD Funster

    Joined:
    Dec 21, 2011
    Messages:
    1,977
    Likes Received:
    1,759
    Location:
    London
    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)
     
    • Like Like x 1
  5. Barclaybasher

    Barclaybasher Funster

    Joined:
    Apr 13, 2012
    Messages:
    2,447
    Likes Received:
    7,093
    Location:
    Derby
    Never ran mine above 3 bar, often at 2bar - whatever was comfortable ....try running at a lower pressure


    (y)
     
    • Like Like x 1
  6. DavidG58

    DavidG58 Funster

    Joined:
    Feb 24, 2013
    Messages:
    6,282
    Likes Received:
    12,118
    Location:
    Bolsover, Derbyshire
    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:
     
    • Like Like x 2
  7. lou020

    lou020 Funster

    Joined:
    Oct 5, 2010
    Messages:
    412
    Likes Received:
    257
    Location:
    huddersfield
    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
     
    • Like Like x 2
  8. buffallobill

    buffallobill

    Joined:
    Sep 21, 2013
    Messages:
    58
    Likes Received:
    46
    Location:
    skipton
    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.
     
    • Like Like x 1
  9. Tootles

    Tootles Funster

    Joined:
    Sep 14, 2013
    Messages:
    8,989
    Likes Received:
    30,879
    Location:
    Lancaster
    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.
     
    • Like Like x 1
  10. Bertie Bassett

    Bertie Bassett Read Only Funster

    Joined:
    Jul 25, 2014
    Messages:
    2,743
    Likes Received:
    8,714
    Our skills in these technical areas are identical, are we related by any chance?;)
     
    • Like Like x 2
  11. Tootles

    Tootles Funster

    Joined:
    Sep 14, 2013
    Messages:
    8,989
    Likes Received:
    30,879
    Location:
    Lancaster
    Must be, David is obviously ex REME.......:ROFLMAO:
     
    • Like Like x 1
  12. Bertie Bassett

    Bertie Bassett Read Only Funster

    Joined:
    Jul 25, 2014
    Messages:
    2,743
    Likes Received:
    8,714
    Clearly, that is a factoid:D!
     
    • Like Like x 2
  13. DavidG58

    DavidG58 Funster

    Joined:
    Feb 24, 2013
    Messages:
    6,282
    Likes Received:
    12,118
    Location:
    Bolsover, Derbyshire
    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
     
    • Like Like x 2
  14. Tootles

    Tootles Funster

    Joined:
    Sep 14, 2013
    Messages:
    8,989
    Likes Received:
    30,879
    Location:
    Lancaster
    Was that for pulling your willy out of your combats, jumping up and down screaming AN ELEPHANT!....SAVE ME!.;):)
     
  15. Bertie Bassett

    Bertie Bassett Read Only Funster

    Joined:
    Jul 25, 2014
    Messages:
    2,743
    Likes Received:
    8,714
    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:
     
    • Like Like x 1
  16. Tootles

    Tootles Funster

    Joined:
    Sep 14, 2013
    Messages:
    8,989
    Likes Received:
    30,879
    Location:
    Lancaster
    His unit was the 47th Spankers..........And the Major was a gay old thing.......:ROFLMAO:
     
  17. icantremember

    icantremember Funster

    Joined:
    Sep 2, 2010
    Messages:
    5,059
    Likes Received:
    7,107
    Location:
    Nr Watton in Norfolk
    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.
     
    • Like Like x 1
  18. DuxDeluxe

    DuxDeluxe Funster Life Member

    Joined:
    Jul 10, 2008
    Messages:
    9,360
    Likes Received:
    25,077
    Location:
    Planet Zog
    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
     
    • Like Like x 2
  19. MikeD

    MikeD Funster

    Joined:
    Dec 21, 2011
    Messages:
    1,977
    Likes Received:
    1,759
    Location:
    London
    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
     
    Last edited: Sep 26, 2014
    • Like Like x 1
  20. sciac2001

    sciac2001 Funster

    Joined:
    Jul 18, 2010
    Messages:
    311
    Likes Received:
    343
    Location:
    Touring Europe long-term
    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!
     
Loading...

Share This Page