Allroad Air Suspension Problems

[Amphitryon]

checked airbags with soapy water and can't see any bubbling there ... compressor is buzzing but don't know if pumps air or not ...

If the problem has gradually been getting worse then the two most likely explanations seem to be a slow leak that has gradually got faster or a compressor that has become inefficient because air is leaking past the piston ring, i.e. the problem Andy's recon kit is designed to solve.

When you say it starts at the lowest level do you mean it sinks to that level when parked from some higher level? If the car sinks when parked that suggests a leak somewhere - if not the air bags then somewhere else. Remember that all four corners sinking doesn't mean that all four corner leak - one can be leaking and the control unit lets the others down to keep the car level. So, if your sure it's not the air bags leaking what about the pipework?

The general approach is fix leaks first, then sort out the compressor if that is not efficient any more otherwise, if you do the compressor first, you can have the compressor go bad again trying to compensate for the leak.

[hubblaz12]

Hi,

I have checked all airbags with soapy water paying attention to where pipework is attached, as also where it leaves compressor and can't see any bubbles. Car sits on lowest level and only barely gets up to allow that lowest green light to stop flashing and be solid green - however yellow warning light starts flashing almost straight away only to get solid yellow in a few minutes. I bought Andy's kit and will try and see if that would help the compressor but ... can it be anything else like ecu ?

[hubblaz12]

Hi, could you be kind and take a look at my few recent posts and let me know what would be your thought on the issue with my car ? Thanks.

[Amphitryon]

Hi, could you be kind and take a look at my few recent posts and let me know what would be your thought on the issue with my car ? Thanks.

Bear in mind I am not the expert here - bagpipingandy is. Yes, there is an ECU and a valve block, i.e. a set of valves that either admit air into an airbag or release some from an air bag to achieve the desired height and to keep the car level. Nothing is immune to malfunction but the impression I get looking back over this thread is that these items are not the usual culprits.

My suspicion is that the warning light is the ECU saying "I tried to get the suspension up to level but had to turn off the compressor before it got there because the compressor got too hot", i.e. exactly what it will do if it is not working very well or if it is trying to compensate for a leak.

So, you have found no leaks. If I was looking for leaks I'd want to be sure I was looking in the right place but if you're confident there are no leaks then fitting the recon kit to the compressor is the next step. I'd look back and find the link to Andy's website and follow the video to repair the compressor taking care to put the new piston ring on the right way round.

Hopefully, that will fix the issue. Even then I'd keep an eye on whether the compressor is running a lot or just occasionally.

[hubblaz12]

Hi,
Thanks. I have replaced piston with Andy's kit and there is a difference. System has cut off compressor two times when on the way up (inside surface of the cylinder is very bad - must be reason for poor pressure) but once there blocked it on max height (two buttons together) and kept height overnight - all wheels has 76 cm from floor to the arch. Does it mean that bags are ok ?

[Amphitryon]

Hi,
Thanks. I have replaced piston with Andy's kit and there is a difference. System has cut off compressor two times when on the way up (inside surface of the cylinder is very bad - must be reason for poor pressure) but once there blocked it on max height (two buttons together) and kept height overnight - all wheels has 76 cm from floor to the arch. Does it mean that bags are ok ?

The two buttons together sounds like jacking mode. That tells the ECU to ignore the height sensors and not try to make any adjustments. The usefulness of doing that is mainly that if one bag leaks that corner alone will sink and the system will not level the car meaning it is then obvious which bag it is.

So, it is good news that none of the corners have gone down. There is one other thing to check - as the height is adjusted the walls of the air bags roll up and and unroll, that means a leak may be apparent at one height and not at another but I can't remember which height is the more likely to expose a leak. That is probably mentioned in some of the earlier posts in this thread.

As for the compressor cutting out part way up, do I take it the fault light remained off? There is a reservoir (at the back, accessible via the left hand side internal door to the CD changer/toolkit area in the boot) so if the compressor was to be able to fill the reservoir faster than the system was moving air into the air bags then it would turn off once the reservoir was up to pressure. Air compressors will always heat up as compressing air releases heat - it's a question of how hot is too hot.

[hubblaz12]

The two buttons together sounds like jacking mode. That tells the ECU to ignore the height sensors and not try to make any adjustments. The usefulness of doing that is mainly that if one bag leaks that corner alone will sink and the system will not level the car meaning it is then obvious which bag it is.

So, it is good news that none of the corners have gone down. There is one other thing to check - as the height is adjusted the walls of the air bags roll up and and unroll, that means a leak may be apparent at one height and not at another but I can't remember which height is the more likely to expose a leak. That is probably mentioned in some of the earlier posts in this thread.

As for the compressor cutting out part way up, do I take it the fault light remained off? There is a reservoir (at the back, accessible via the left hand side internal door to the CD changer/toolkit area in the boot) so if the compressor was to be able to fill the reservoir faster than the system was moving air into the air bags then it would turn off once the reservoir was up to pressure. Air compressors will always heat up as compressing air releases heat - it's a question of how hot is too hot.

I will now leave car on the jack mode on 3rd lvl overnight and measure in any of bags went down.
On lvl 3 all corners are 74cm from the floor to the arch edge.
Correct me if im wrong but i think that leaks should be more apparent when on highest lvl as whole bag is extended and on highest pressure.

[hubblaz12]

The circlip holds it in place, remove circlip then the disc will come out, however there shouldn’t be a hole is it not leaking from the edges? Do you have a photo

Hi Andy, your kit is awesome. My allroad is again driveable. Compressor still works a lot but suspension keep its height.

[bagpipingandy]

I’m glad you like it,

Does your car sink at all if left parked? Leave it on lowest setting and report back if it sinks

Best Regards

Andy

[hubblaz12]

I’m glad you like it,

Does your car sink at all if left parked? Leave it on lowest setting and report back if it sinks

Best Regards

Andy

Hi,

I've been leaving it on top 2 levels so far and no si king but will lower it to the lowest level now and check. Will report back.