Replaced the seals in the compressor. Still receiving: "vehicle too low" and "Air Suspension Fault" messages.

Have left the skirt off the wheel well & can observe the compressor. It turns on when the car is turned on; stays on for awhile, turns off and then comes back on & repeats this process.

Earlier, air tested the left front shock and found no leaks.

Now, trying to decide how to proceed.

Since, while the installation went well, I assume the compressor is pumping air. If I removed the fitting in the air export, could I test the compressor to see if adequate air is coming out?

Assuming the compressor is working properly, how does the system work from there? Does each shock fill and retain its own air, so that, if one leaked, the others would fill properly? Or, are they all tied together, so that, if one leaks, they all leak?

My gut is to disconnect the air at the compressor since it is readily accessible and see if a lot of air is being pumped first. Obviously if little or none comes out, it is the compressor.

Any thoughts? Thanks.

 

Observed that when car started and compressor engaged, front lifted 1.5 - 2".

When compressor stopped, left front started to lower. I think the right did as well; but would have to measure to be sure.

Disconnected left front shock. Air came out. Started engine. Air was coming out of the air hose. I could stop the flow with my thumb. When I reconnected the air hose to the shock & restarted the engine, could see the front end rising (same amount as previously observed) Then a shrill whistling sound was heard in the area of the front shock. It is my sense that at a certain pressure air is leaking in the front left shock; hence, it only goes up so far. Could not observe further because the compressor won't operate if i lift left side and remove wheel.

Disconnected the right shock air hose. Seemingly, a lot more air escaped. It seemed to rise & fall similar distance as the left side. When compressor engaged.


Questions:

1. How much does the front end actually raise up when functioning normally? Based on the "Vehicle Too Low" warning, it is more than what I'm getting.

2. Should I be able to stop the air flow with my thumb placed over the air hose to the shock? Idea being: is this sufficient pressure? Obviously, enough is coming out to raise the car; so, maybe that answers it in the affirmative.

3. Does anyone know if there is anything else in the vicinity of the left front shock that could be producing this loud, shrill whistle.

Conclusion:

Unless there are other suggestions based on the above, I plan to order a front shock & see what happens.

If you're still reading this, thanks for your attention. Any thoughts much appreciated.

 

All air springs are individually supplied with air from the valve block. Pressure in the springs is pretty high at around 15 Bar (=220 psi).

On my own car when I start the engine, it raises slightly. Similarly it seems to drop a bit when I switch the engine off, but it doesn't go down any further overnight. I have no fault displays or anything. On shutdown most times there will be a whoosh of air that is the system clearing out the water trap in the compressor. This always gets people alarmed, because the driver handbook has nothing in it about this action.

Really you should not be getting any whistling sound once the system has raised the vehicle so it sounds like you have a leak somewhere. As you are in the US, you can get Arnott rebuilt assemblies that have a new air spring diaphragm in them. These are much cheaper than new springs from Bilstein.

The front air springs are controlled as a pair, the rears individually, so if one of the fronts is leaking it will allow the front to drop and bring up a fault display.

 

You have eliminated the compressor and it is running so you can forget about that.

I think that I am right in saying that the air suspension shocks can leak only

some of the time possibly because the rubber bellows folds over itself depending

on the height.

You can pressure test an individual spring by fitting a test gauge, pressurising

the shock and watching for a pressure drop, however you would need to make this fitting.

It sounds as if you have identified a leak on the left front.

 

Will remove the front left shock over the weekend and await the delivery of rebuilt one.

Will let you know how I come out.

Thanks for all of your help!

 

The bolt holding the bottom of the shock could be v. difficult to remove-

you may need an impact driver otherwise removal and replacement is

straightforward.

Not that I have done it myself!

Good luck

 

Meirion, thanks.

Yes it is a relatively easy task to remove the shocks. As with all of these things, having a generous supply of the proper tools is perhaps the most important ingredient.

I've been accumulating tools since the 60s when i worked on my '67 Healey 3000 MK lll; it was supposedly the 7th to the last to be imported to North America. If only I had continued to do my own work for all of these years, I suspect I would be quite good at all of this. With the Healey, I would frequently mal-adjust the dual carbs before i picked-up my date so that i could impress her with my skill at fixing the erratically running engine. Those were the days! Now, my wife of 45 years is still somewhat dumb-founded that I can do these things!

Thanks to this site and other internet sources, with the proper tools and some aptitude, I have been able to: replace pads and rotors; repair faulty AC, etc. Tasks that I had thought, with all the advances in technology, would have been jobs for my mechanic only. I encourage anyone to attempt similar repairs; it is a quite rewarding endeavor.

This air suspension system has been the most challenging repair I've attempted to date. While I may end-up taking her to the mechanic, I'm so fascinated by the technology that I will endeavor to, through process of elimination, fix this myself. I am also hopeful that I can figure-out how to get this code reader I recently bought to work some day; it would be quite helpful.

Appreciate your attentiveness to my posts and willingness to be helpful. Steve

 

It would help to get the codes read to see if the compressor is filling too slowly. If it is okay, then you have a leak and it sounds like the one with the air noise. I have had the same problem and I could hear the air coming out of the shock unit. Replacing the shock is not too hard and there are plenty of write ups in here on it. Basically, I just jack up the car at the wheel I'm working on and remove the wheel. I then disconnect the battery to keep the leveling system from losing its settings. I then unbolt the sway bar link, unbolt the upper control arm from the hub carrier, being sure to keep the ball joint from turning with a wrench, unbolt the bottom of the shock, disconnect the electrical and air fittings at the top, and unbolt the top. Then maneuver the shock out and reverse the procedure, reconnecting the battery before lowering the car.

 

Thanks, Oldmots.

I notice that since I replaced the seals in the compressor, the shocks are moving the car more.

I should receive the new shock tomorrow; I have removed the suspect shock & will replace it with the rebuilt one when it arrives.

Either way, you are absolutely right about reading the codes. By all account, my reader should be able to read the requisite "C" codes. However, it isn't. I will expend some effort soon to establish why I am not getting them. The manufacturer of the reader has a pretty robust forum. I suspect that I will be able to get a resolution there.

Thanks for your help.