I have a 3.0 td6 RR on the way back from holiday the suspension stopped working and dropped to bump stops with air suspension inactive, when outside of the car and shutting the drivers door with engine running the front lifts but will not stay at height with a hissing coming from behind the front drivers wheel is this a leak or normal?

No this is not normal, the hissing sound will be an air leak, from one of the following -
Airbag / air line to the bag / valve block ( Situated on the back of the front offside wheel arch, behind the arch liner) / air line to the valve block. Best to jack up the front off side, remove the wheel and maybe remove / bend back the wheel arch line to get a good look. Once accessible if you cannot see a leak, spray water on the parts to see if that shows the area where the leak is.

Thanks for this will check this out, I’ve never heard the hissing before and it says on the Hawkeye cannot read a level so probably not getting to ride height to switch off pump due to a leak?

Sounds like the rate of the leak is higher than the compressor capacity. I forgot to mention that the air reservoir cylinder is situated on the offside under the car between the wheels, worth checking the line from that to the front air distributor valve block as well. Good luck

Cheers bud i will let you know how i get on.

I have a similar problem but no hissing!

Each morning i go out and the car has lost the air and as soon as i start up the compressor kicks in and we're away.

I guessing the pump needs reconditioning…..maybe same with yours? Could the hissing be coming from the pump?

This may not help, but......
My 2006 has always been reliable regarding the air suspension, but ......Previously I never heard the air compressor running unless I opened up the spare wheel well. Recently there was one incident where the wheel well partially filled with water and for the life of me I could not find the water entry point or replicate the entry using a hose pipe.
Since then the air compressor is 'Just audible' when it runs. So now when I have parked the car overnight or for two three days, when I start it, the compressor will run for 30 to 40 seconds, but the suspension never drops.

I am assuming that between the air compressor and valve blocks there will be a very slight leak but cannot hear anything, will be time for a soapy water spray. Also, I am assuming that built into the air compressor outlet / air reservoir there must be a non return valve, so will have to check that when I over haul the compressor later this year. Cannot do that right now, as I am packing to go back to sea for months so will check later this year.

Funny you say that, I’ve just purchased my L322 ( about 1 year ago ) when I got it I pulled the spare wheel out to check and clean the wheel well out as you do and i found 1/2 a bucket of water in there
The radio was under water as well hence I’m looking for some sound .

The compressor is noisy I hear it every time I first start up in the morning, needs a rebuild, I’m guessing it would leak air back past the piston ring (maybe )

Luckily in mine, the water was only in the wheel well, no water in any other compartments, tried every which way to replicate the leak / water entry, to no avail.

If yours is anywhere near the age of mine, now 16 years old, it could probably benefit from a compressor over haul
I have an over haul kit, but will have to do the job later this year as I have run out of time. Looking at my compressor it looks like it has never been opened up, car has now done 98000 miles, so in my opinion the compressor has done well so far, but will overhaul it to maintain reliability.

Plus, remember that if you have wheels off the ground / work on the air suspension, afterwards, always carry out the front wheels lock to lock reset, don't really know if this is ALWAYS required, but it does seem to help.

Another point that people forget, is Haylands excellent post....'Use it, or lose it' I always operate the air sus to all levels every week and when carrying out my two weekly check / test everything checks. That way if I discover a fault the car is at home where it is easier to fix