Air suspension leak

[gypo]

I’ve retro fitted air suspension on the rear of my van, this was done about 4yrs ago and has been fine. However I’ve noticed over the last year that it is slowly loosing air.
Has anyone used tyre seal in the system to stop a leak, the stuff you use in tyres.
Thanks
G

 

[caledonia]

Don’t think that would be a good idea. Why don’t you find the leak with some soapy water and repair it?

 

[witzend]

Don’t think that would be a good idea. Why don’t you find the leak with some soapy water and repair it?

I'd agree can't be many joints to check the pipes and joints are small and the tyre repair stuff could cause a blockage in them

 

[mjvw]

I had an issue tested with soapy water as advised on motorhomers and it turned out to be the air top up Schrader Valve leaking replaced for pennies, very simple setup of a couple of air bags placed in the rear spring connected by rubber pipes with plastic T connectors.

 

[izwozral]

I had a slow leak and could never find the source, I just topped up the offside every 3-4 days and never stressed about it.

 

[gypo]

Thanks all, the leak is so slow I think I might struggle to find it but I will give it a go.
Cheers
D

 

[Wooie1958]

I had a slow leak and could never find the source, I just topped up the offside every 3-4 days and never stressed about it.

Same here, i`ve checked it and AS have checked it when it went back in for a new compressor ( under warranty ) a while back and neither of us could find it.

I need to top up every week or so and it literally only takes a 2 second shot of air with the switch on the dash to top it up so that`s what i do.

 

[SquirrellCook]

£800.00 later and my Plaxton still leaks, to wet and cold to investigate. When I do it'll be soapy water in a hand sprayer. Just hope it doesn't fine any more expensive bits

 

[Deneb]

Pump it up to 100 psi or whatever the maximum pressure is for your system, and apply some gentle heat to the pipe unions at the valve/gauge/compressor and the airbags with a hairdryer. Don't overdo it or you might melt the pipes, you only want to soften them slightly.

Keep the system inflated to maximum for a couple of weeks then return to normal pressure. If it continues to leak in the meantime you will have to start looking for a leak with soapy water, but if it is only a very slow leak from a pipe union that you can't detect with soapy water the above procedure may well fix it.

 

[gypo]

Many thanks, I will give that a go over the weekend

 

[Nabsim]

Not related to your problem but I once lost pressure on on bag after leaving the van parked one side on a kerb all day. Maybe half a bar dropped at most. Topped it up and never seen it again but wondered if having same pressure both sides in that situation caused it.

 

[gypo]

Hi, both bags are linked to one valve so they are equal .
Thanks

 

[Deneb]

So are mine, but don't you have isolating valves in the lines to each bag that you open to inflate and close in normal use? If not, the system won't work properly because when the weight of the vehicle is transferred to the outer wheel when cornering or on bump compression, the pressure in the bag will transfer to the unloaded and opposing bag, equalising the pressure across both and defeating the object of the suspension.

 

[gypo]

No I don’t think so, both line come to a tee that then goes to the gauge

 

[Deneb]

These are similar to mine. Obviously you only need one, but the photo shows different configurations for the valve block. Without separately isolated circuits to each bag the pressure will remain equal in both in all conditions, which is not what you want. Instead of the bag on the outer wheel providing full resistance during cornering whilst the inner bag unloads, you will have reduced resistance at the outer wheel and the bag at the inner wheel will actually increase body roll. It could be quite dangerous if you had to make a sudden turn or avoidance manoeuvre.

You open both valves to inflate the system when on a level surface, which will equalise the pressure in both bags. Then after closing the valves, each bag will act independently in use.

 

[gypo]

Its been fitted for at least 3yrs with no problem, thank you tho for the info.
I’ll do some research

 

[Deneb]

This is just one quote I found with a quick search.

In today's air suspension system, valves play a critical roll in isolating and controlling where air is directed and how. Early generation air suspension systems were two-way setups. Essentially, each left and right air bag was connected by a line and shared air. As the vehicle cornered, one air bag compressed its air and pushed it through the line to the other air bag, which was expanding. This resulted in severe body roll and accounted for part of the reputation air suspension systems had for causing a terrible ride. Now, systems use a series of valves that control this tendency and offer bettering handling.

You may not notice it in normal moderate driving conditions, particularly as you are obviously used to it. But you are effectively only getting half the resistance you should from the bag under compression and at the same time inflating the opposing bag which should be unloading, both of which will increase body roll.

 

[gypo]

Thankyou for the info