I just replaced both bags and thought my issue was solved but I took measurements last night and this morning the rear was about 1/2” lower but raised back up as soon I started the car.

While changing the bags I checked for leaks on the solenoid with soapy water but didn’t see anything.

So it’s absolutely not normal for it to sag a little overnight then???

Where else could the leak be coming from? It’s driving me nuts, all the threads are about just replacing the bags and fixed.

It's not normal to sag. Actually bags should not lose pressure once they have been installed. Did you check the hose lines that goes all the way to the compressor?

Yes I checked the solenoid front and back for leaks and nothing.

Can't check the top of the air springs because you can't see it once inflated.


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You may have mentioned it elsewhere, but what kind of bags did you use and how did you install them?

Did you removed the compression fitting from the new bag or mess with it at all?

I installed Arnott bags, they come with a pre-installed brass fitting and their instructions say specifically not to remove them and just insert the air lines in and tug to check it's on tight.

So that's all I did, I removed the stock brass fitting and just plugged the bare line into the Arnott bag. It was on tight as I couldn't pull it out again unless I ripped it off.


Which now has me wondering what do if I need to replace the Arnott bag in case they are faulty? Cut them off?

Also, it could be possible that only one bag was maybe faulty to begin with as I doubt that both could arrive to me defective.

So was also wondering if only one is defective and one is sagging, will the "self-level" try to adjust the other side to match?

I also used Arnott and have had no issues (installed more than a year ago). The instructions were as you described and I followed them to the letter. Now, is the overnight drop consistently happening? Eg the compressor starts as soon as you get the car opened, etc... if this is the case, you may have a leak; could be a bag (best scenario) or somewhere else (compressor, tubing, etc -)....suggest to check behaviour for a few days....

Based on that, I would doubt the bag/s are defective/damaged unless you had the bag installed with no air and all the weight of the vehicle on one or both.

Next question/s,

1. How did you deflate the old ones to remove?
2. 1/2 inch over night or extended period - could be wrong but soapy water may not be good enough to spot a leak where the lines connect to the pump. Somebody can correct me if that's untrue. When I changed mine, I experienced the same problem and simply tightened down both lines at the pump slightly, until there was no more sag. I was afraid to over tighten since the fittings are threaded to plastic. Have you tried making sure those connections are tight enough?

I deflated the oem bags by unthreading the brass fitting on the compressor solenoid (Red and Blue) Waited till the hissing stopped for the majority and did each side one side at a time.

And I didn't inflate the new bags until both were on the car and loaded on it's own weight.

I've read lot's of warnings to not do this.

Emphasis mine. I'm not sure exactly why, and you may not have damaged anything - I would still check the connections to the pump.

I had my new Arnott bags fitted today I got them from ebay and paid £300 for the pair my indy fitted them. I'll be keeping an eye on if the bags are losing air with the tape measure.

I also found this on the web which is an interesting read on the self levelling system and the different functions it performs at any given point of time.

https://www.newtis.info/tisv2/a/en/e...ontrol/Xs0tfmb