Possible air leak, where do I start?

[Mechcanico Lee]

On the a8 if you set to max height and switch car off and lock it up does it stay at max height or drop itself to normal height as a default .

If it stays at max ride height after locking leave the car in that state , if the cars stays up and does not drop it is not pipe work / valve block / corner valves it will be the air struts .

What happens with the the air bags ..... at normal ride height the rolled edge of the bag that is exposed gets micro cracks and can weep , if you put to max height the same rolled edge is not exposed and the cracks are not forced open as you are at a different area on the bag , bit like an old tyre ..... you see the cracks where the tyre sits on the ground and it bulges out .

I do a lot of Range Rover / discovery suspension air bags this is how I check to see if it's the bags

[Architex_mA8tey]

Originally Posted by Mechcanico Lee

On the a8 if you set to max height and switch car off and lock it up does it stay at max height or drop itself to normal height as a default .

If it stays at max ride height after locking leave the car in that state , if the cars stays up and does not drop it is not pipe work / valve block / corner valves it will be the air struts .

What happens with the the air bags ..... at normal ride height the rolled edge of the bag that is exposed gets micro cracks and can weep , if you put to max height the same rolled edge is not exposed and the cracks are not forced open as you are at a different area on the bag , bit like an old tyre ..... you see the cracks where the tyre sits on the ground and it bulges out .

I do a lot of Range Rover / discovery suspension air bags this is how I check to see if it's the bags

If you switch the car off it will always lower back down and sometimes you can even hear the compressor vent as you do it. if you leave it in lift mode then select setup>jacking mode>on it will be locked at height

[Mechcanico Lee]

So Op if you do what Architex says there and it stays up sort of proves the pipe work and valve block are not leaking air

[Darius]

Thanks for advice, will give it a go. Had no time yet to check valve block.

[Delboy]

While putting the car in jacking mode may indeed help show if you have a leak, it will not tell you where it is leaking.

In normal operation the car can wake up and adjust suspension while it shut off, putting it in jacking mode prevents this by no longer adjusting suspension and ignoring level sensors while its activated.

The air pressure is still held in the struts by the valve block being closed, so if there is a leak in the line or valve block it will still show up as a strut being lower.

Only definitive way to determine if its a strut or something else is to isolate the strut using a separate valve like the one in this thread

[Mechcanico Lee]

Good info Del, suspension height monitoring whilst vehicle is asleep can affect your diagnostics , range rovers/ disco 3 and sports do the same , periodically whilst asleep suspension ecm wakes and looks at vehicle level , if a strut has sank the ecm lowers all other struts to that level , so for one leaking strut the whole vehicle ends up sat on its arse , and because when the network wakes and it has to 'take action ' to lower the car this keeps the network alive for 20 mins or so pulling out amps .....so after a week or something you end up with a car sat on its arse and the battery flat due to constant waking up and taking action .


On the land rovers i set to normal height pull air suspension maxi fuse and then park up , air suspension now is dead so no intervention , after a few days see if one particular wheel has dropped ......this obviously tells you which air bag is leaking .....arrrrr yes but it could be pipe work or valve block or joints , so refit fuse set to max height re pull fuse , if vehicle stays at max height you know its not pipe work joints and so on .If it still drops at max height then you know which pipe/connections to give extra investigation .

Most air suspension systems are similar so would of thought you could try this on the 8 , ive tried spraying leak finder on the bags ..... you just cannot get to them even on a drive on ramp due to wheels and suspension in the way ,and you need to spray the bags at the normal ride height so its difficult .

The shut off valve tool there could be very handy aswell