Front air spring strut replacement

[rogerkiu]

Very interesting, I found that my front air bags held very well in recent weeks. After overnight (over 10 hours) sitting in garage, both front left and right air bag hold pretty well. One thing I found that, after overnight sitting, both front left and right drop a little bit but not noticable, I guess maybe only 5mm. Is it normal or it just leaking very very slowly? What is your suggestion? Should I still go changing both front left and right air struts or just hold until significant leakage found?

[phildg2000]

Originally Posted by Turbo_Bimmer

Just to let you know, I ordered the air spring only from Arnott, and it is an easy job to replace, and if your shock absorber is good, it is cheaper to replace the air spring only.
You just need to be carefull when you insert the new air spring on the strut and make sure that you use a silicone grease for sealing and ease the sliding of the spring over the 2 rubber o-rings, and push with a slight L-R-L-R movement to move the air spring to the bottom of the seat.

Hi Turbo_Bimmer, I am trying to install Arnott's fron right air spring only and as I look at the spring, I'm a bit confused as to why the metal head of the air spring is fixed while the original one has a rotating head. Also, did you have problems with the air connection line? Thanks!

[Turbo_Bimmer]

Originally Posted by phildg2000

Hi Turbo_Bimmer, I am trying to install Arnott's fron right air spring only and as I look at the spring, I'm a bit confused as to why the metal head of the air spring is fixed while the original one has a rotating head. Also, did you have problems with the air connection line? Thanks!

Hi, the metal head of the Arnott's spring can rotate like the OE one. It's because they are new that they don't rotate as easily as the BMW ones. Grab it with one arm and you should be able to rotate the upper portion, and position it correctly vs the strut.

The air inlet on the Arnott's unit is not drilled at an angle like the BMW one. Instead of pointing down at 45°, it is horizontal which makes the connection of the hose harder. I don't know why they did it like that though.
Also, the fitting on the Arnott's spring was not compatible with the tube. I had to remove the fitting from the BMW spring and install it to the Arnott's spring.
On my truck, the hose was barely long enough to connect to the newly positionned fitting, but it worked.

[e39_touring]

Originally Posted by rogerkiu

Very interesting, I found that my front air bags held very well in recent weeks. After overnight (over 10 hours) sitting in garage, both front left and right air bag hold pretty well. One thing I found that, after overnight sitting, both front left and right drop a little bit but not noticable, I guess maybe only 5mm. Is it normal or it just leaking very very slowly? What is your suggestion? Should I still go changing both front left and right air struts or just hold until significant leakage found?

Keep in mind that temps decrease overnight, and lower temps equals less air volume. (~1 psi for every 10 degrees cooling) Leave the car a few days, and if it keeps dropping, you have a leak. Otherwise, just chalk it up to normal air expansion/contraction with temp change.

[sockethead]

Originally Posted by rogerkiu

Very interesting, I found that my front air bags held very well in recent weeks. After overnight (over 10 hours) sitting in garage, both front left and right air bag hold pretty well. One thing I found that, after overnight sitting, both front left and right drop a little bit but not noticable, I guess maybe only 5mm. Is it normal or it just leaking very very slowly? What is your suggestion? Should I still go changing both front left and right air struts or just hold until significant leakage found?

Originally Posted by e39_touring

Keep in mind that temps decrease overnight, and lower temps equals less air volume. (~1 psi for every 10 degrees cooling) Leave the car a few days, and if it keeps dropping, you have a leak. Otherwise, just chalk it up to normal air expansion/contraction with temp change.

You could spray the bags with some soapy water and see if they bubble up anywhere. One may be leaking and the system will compensate by lowering the other one. It's usually the left one that starts leaking first. Remeber if you find one that is leaking, the rest aren't far behind.

If you determine that they are leaking, change them before you get the dreaded air suspesion inactive message. It will save you $$ and a lot of headache

It seems that, in general, all of the airbags are reaching their end of life in these vehicles...