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Just when I had fixed the last outstanding fault on the car a new one appeared.
I was raising the suspension using a diagnostics tool as it had gone flat from sitting for ages and I found the left rear bag only takes around 2.5bar of pressure before something bursts and all the air rushes out.
Anyone know what component causes that problem? 2.5bar isn't enough to raise the car but pressure has to build in the system before it'll burst open and leak out all the pressure. The right rear side is not affected so this isn't common across the rear axle, the front also has no issues.
I think if it was a standard leak I would have found a hose had popped off but that's not the symptom as the system holds pressure and releases it all in one big woooosh.
So it's a problem only on one rear corner and not a lose hose or perished rubber or anything like that as far as I can tell.
Assuming your car has rear airbags, seems like the bag is no longer useful. If you heard it explode time to purchase new rear airbag(s), and honestly when one side goes the other is soon to follow unfortunately...Just my opinion. GL
R,
2Merks
I already replaced the airbag on that side a few months ago.
Has anyone had an issue where the rear bag fails so soon after installation? The car has not done many miles with the new bag... maybe a couple of thousand since it was installed.
Next step is the soapy water test. Be sure to inflate the bags to their highest level and have the weight of the car on them in order to pressurise them to find a leak - unless of course its a very obvious one. Be very careful getting underneath it even with jack stands. If the car falls/bag bursts, it will crush you.
This is not a slow leak. When it gets to 2.5 bar it suddenly lets go and all the air gushes out. Soapy water wouldn't do anything useful in this scenario.
I think potentially the only way I'm going to be able to diagnose this is to get it up on something to sit the wheels on. With jack stands at the jacking points the pressure does not build up in the bag. So at the moment I've only been able to run the pump with the car sitting on the ground and that does not allow observation as the wheel is right up in the arch blocking view from either the side or from underneath.
Perhaps a better idea is to take the wheel off and then I can look in from the side to see where it is leaking.
Remove and replace the air spring. Yes, I have on two occasions had air springs fail; once on initial installation and once after a couple of months. Both replaced under warranty although all labor was performed by me.
Perhaps a better idea is to take the wheel off and then I can look in from the side to see where it is leaking.
I would do this, but place a piece of 5x5 or similar under the suspension arm so the suspension can be lowered to normal height. And stay away from the wheel well when compressor builds pressure.
Remove and replace the air spring. Yes, I have on two occasions had air springs fail; once on initial installation and once after a couple of months. Both replaced under warranty although all labor was performed by me.
This is potentially the issue. Did you have the same symptoms where it tries to fill and then bursts and drops again? That's what I'm getting. It will hold 2.5 bar of pressure before it releases.
This is potentially the issue. Did you have the same symptoms where it tries to fill and then bursts and drops again? That's what I'm getting. It will hold 2.5 bar of pressure before it releases.
In the second case, yes. Holds pressure, lifts, then the tear in the air bladder is exposed and vents to atmosphere.
In the second case, yes. Holds pressure, lifts, then the tear in the air bladder is exposed and vents to atmosphere.
This makes sense to me judging by the symptoms. I can't find any hose splits or hoses hanging off.
The bad part of this story is that this likely burst bag was replaced quite recently and the one which came off was likely better quality but I have since disposed of it.
These new Chinese bags off ebay are so cheap now I'm going to have another go and see if it was just a one-off. Only £65 for another new bag.
Its most likely in the airbag. The rear bags are fed of 1 line from the front. There is a Y-piece right behind the rear differential.
I think you can actually inflate the bags individually from the tester. But the axle on the whole does seem to operate as a pair of bags rather than being able to put one side or the other. Think due to there being only one level sensor. I guess the electronic part of the airbag has something to do with controlling the inflation by diverting air or putting it into the bag.
Sods law... it was not the airbag. There was a split hose but it wasn't visible until I had the wheel off and started taking it apart to fit the bag. So I can return the new unused bag... something I'm sure will be thrilling for the supplier, they always like to take stuff back. I just know though... if I had not bought a new bag ahead of time then it would have been the bag that failed because I didn't have one available.
I managed to get well past the 2.5 bar it was originally bursting at. The hose was the thick rubber one going to the reservoir so it was taking some pressure before the split would open up. I came off this screen for the corner strut after I had put enough pressure into it for holding the strut in place and then raised it 64mm using the automatic function thereafter.
Good news you found out the root cause of the issue. This is not really a known issue, so good that you replied back after fixing it
I think by this stage when these cars are as old as they are anything is possible. It will have had repairs on the airmatic before so something done previously could be the reason it has failed in this unusual way now.
03-25-2024, 10:50 AM
