Ive tried on the on-board tyre inflator and no air at all is received from the compressor. So I guess the compressor is not moving any air - would that suggest the compressor itself is the culprit?

Today I got the compressor off and used one of those compressor repair kits - new rubber seal and piston ring. Posed it back on the car and cleared any fault codes using VCDS. Whilst I can hear the compressor make a noise nothing happened - the accumulator tanks didn't fill and no raising of the suspension

Could that be a sign the compressor is just not strong enough and hence needs replacing? Im still no closer to resolving my issue but ill keep plodding on trying to fix - just wondering if its time to shell out for a new compressor or if thats a waste of cash at this time?

Also just a question - may seem stupid to some, but the actual suspension boots - if these are torn would that cause a leak? the reason I ask is that the rear two are torn on mine and have been for years yet air suspension always worked. Just wondering if the outer boot being torn is an issue or not?!?!?

 

Based on your info and comments I would start looking for leaks between the compressor and tank.

A spray bottle of soapy water may be able to help you find a leak. Although you will likely need to remove the underbody trays to follow the lines as much as possible.

Also double check all of your lines from the compressor as they may not be seated properly after the compressor rebuild.

 

I took the compressor off completely and just ran a live / ground to confirm the compressor runs

it does BUT there’s hardly any pressure coming out !

someone mentioned a membrane inside that helps build pressure and if that’s worn / torn then it can’t build the pressure

im wondering if that’s what’s happened and so it’s time for a new compressor

 

Ah! Sorry didn’t get that. (Old main brain installed at the moment)

A comment / question here to the other more knowledgeable members of the forum....

The way I see it, I can understand that the compressor may not be building pressure now, but I can see how that would cause the suspension drop in the first place. I would assume that once the shocks are are charged they generally stay where the are. A sudden drop would indicate that the shock itself has leaked. Was it both sides or just one corner? Perhaps you had a leak in a junction block somewhere?

 

well it’s ALL FOUR corners all dropped completely

with regards to shocks I’m pretty sure that’s just about how it handles movement on the suspension so like soft hard etc

whereas to allow the suspension to drop completely that is complete lack of air I’m presuming

strangely when I removed the air hoses the blue one did have about 30 seconds of air that cane out - god knows from where lol

 

Try this chap. Very helpful and his rebuild kit is excellent.
https://www.bagpipingandy.com/

 

Evening all

bought a cheap compressor off eBay 2 year warranty just to see if it was the compressor

happily to say it all kicked into life and the suspension went up!!! I’m sooo happy

now I know I can’t get the wabco fixed and I’m back in the road

thank you everyone that helped me with this

maybe what I went through will help others

 

Great news. Wonder why the rebuild kit didn't resolve the issue when you installed that. Maybe there was something more wrong with the compressor.

 

well apparently there are beads inside that help create the compression - these wear and I’m guessing there are bigger ‘kits’ that include these beads and other parts that wear on these wabco

the bagpipes guy that makes the £25 piston ring kit I think also does the bigger kit so I think I might get him to overall my wabco

 

The gasket rebuild kit only works if the compressor still functions but is "slow" due to small leaks. Too much wear needs something else.

 

Good news and happy owner : )

 

So the compressor is all good and raises the suspension as it should. However I have now found that each morning the two rear wheels are back down to the lowest they could be, whereas the fronts are raised correctly

I guess this is showing I have a leak
somewhere - but tbh I don’t know where to start

I've heard it’s worth spraying washing liquid around places - I’m guessing the two struts at the rear? Anywhere else I should be looking that affects the rear suspension?

 

I doubt both rear air springs failed at exactly the same time. Follow the lines and I think they'll go to some kind of air distribution block. Maybe that has 2 chambers - one for the front and one for the rear - and the rear chamber is leaking. I'm guessing at all this as I haven't had to work on my air suspension yet 🤞

 

The valve block is right by the compressor in case you want to check.
The workshop manual shows this schematic of the system and seems that the rear struts get the air from one single line. One would think the rear accumulator should be connected to the rear struts but it seems is not the case?


Edit: This one from the parts catalog seems to be more accurate with the lines:


Item 5 line to rear left strut
Item 6 line to rear right strut

Looking at the system and considering that both rear struts or both rear lines wouldn't fail at the same time as Petza914 points, I'd say you are looking at something wrong with the valve block maybe? No fault codes?

 

Wow that’s really useful Information thanks so much
What software did you use to get that info mate?

as regards errors I’ve used both VCDS and icarsoft POR 2 and none given any errors now from the Level Control Module

once I turn the car on the car levels out fine and stays fine all through driving. But park up and leave overnight and the rear two lower right down. Front stays up

SO I guess when we finally get the rain stopping I’ll see if there are any leaks on that one line then

again thanks for the info!