# Newby - suspension air bag pressure.



## itspilsbury (Oct 13, 2014)

Hi everyone. From my previous posts you will see I am new to motor homing having recently purchased a 1999 Citroen C25 Hymer 564. Many years ago it had its rear suspension upgraded with air bags. In the toilet cassette compartment are 3 tyre valve type valves and two pressure gauges. One valve is for left air bag, one is for right air bag and the other I'm assuming inflates them both simultaneously ??? There is dymo tape saying 2 bar pressure for low weight and 2.2 bar for fully laden. When fully laden the leaf springs are slightly bent down. Does anyone know if it's okay to put in more than 2.2 bar and if so how much pressure would still be okay so as to make the a bit less saggy. Thanks again.


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## bognormike (May 10, 2005)

hi there;

I put mine between 2 & 4 depending on loading. 

How on earth do you get something in there to blow it up? Mine has a built in compressor unit.


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## itspilsbury (Oct 13, 2014)

Just a normal airline hose, fits easily.


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## philoaks (Sep 2, 2008)

I've got Dunlop airbags on my van (but I would guess the Firestone ones would be similar) and the maximum inflation pressure recommended by the manufacturer is 7 bar. 

Having tried it at that pressure once, the only time you would ever put that much in would be to lift the van to clear an obstruction. Using it on the road at that pressure it feels like the axle is welded direct to the chassis with no suspension at all!!

As Mike has said, somewhere between 2 and 4 will generally do the job but it's just a matter of playing around and finding the balance between ride height and ride comfort.

Phil


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## valphil (Sep 5, 2012)

Yup , between 2 and 4 for my old 93 Hymer , unless I'm levelling on a sloping site


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## itspilsbury (Oct 13, 2014)

Thanks everyone my two gauges only go up to 4 bar - 60psi so I have gone above the marked 2.2 bar for fully laden to 3 bar and will see how it goes. Obviously the air bags are very old, I guess 20 yrs so I hope they will be okay. The leaf springs look more level now anyway.


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## powerplus (Oct 6, 2014)

hi
if your air bags are 20 years old
it may be worth just checking that the rubber is not getting splits in the surface

i have recently fitted airbags to my 2011 fiat mainly to increase height on ramps

i would blow the bags up to see how much pressure is needed to lift the van up as high as it will go jest measure the wheel arch to the ground
and compare it to before they were blown up

luckily my springs had not sagged so will go with about 2 bar and just raise the back a little from standard bit i have the ability to raise if needed for ramps

look to see what the springs look like with 2bar in them if your springs have sagged a lot you may need a little more pressure

it may be worth also looking if there is a makers name on the air bags


barry


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