E55 was parked for a month between moving to a new a house and of course the car suffered a bad passenger strut the day before my move. Although I was able to drive car 30 miles and park at my father's until I fixed it. I had no dash warnings or codes thrown which I thought was a little odd. But the wheel was tucked and unable to raise. Even by using and testing system through Star it did not tell me there was a problem and showed the strut filling to same bar as the rest. So I winged it and bought an arnott.
After all the reading I did with people using 5v and or having to cycle there key to let the air out of new strut for it to fit had me thinking it would not be a super simple job. Well I was able to easily fit the fully pressurized arnott right into place without having to do anything special... It was the easiest replacement strut I've ever done.

My question is why are people having to drop the air out of the struts to install them? And my suggestion for anyone getting ready to tackle one would be to order some new upper ball joints if there old, they are very cheap and you have to pop them off anyway. And have a medium sized prybar handy. I did not need star for any point of the install/uninstall. If your like me and read a ton of posts of people taking hours and hours for the install, don't be worried. It's very easy.

 

If the strut has 12 Bar in it you might want to reduce pressure...One uses DAS to lower the pressure to 3 Bar to replace a strut. If the strut has a leak, it is most likely at atmospheric pressure so replacement is easy. A new strut is most likely at 3 Bar or less so installation is no issue. It is when a strut is at 12 Bar you might have a bit of an issue.

Front struts are a bolt on and fill using DAS. Or take a chance and just drop the car and throw the dice that everything inflates properly when you start the car.

The rear air springs are a whole different ball game. One must use DAS to properly install the rear air springs and I can state from experience one wants no pressure in the air springs when installing; they tend to bend into a "L" shape if pressurized. Urk!
Proper procedure:
-Install rear air spring, install but do not tighten lower bolt
-Use DAS to fill air spring with ~0.5 Bar pressure
-Use jack to raise axle shaft to -1.2 degrees
-Use DAS to fill air spring to ~2 Bar pressure
-Inspect air spring to ensure bag did not deform sideways (always a PITA)
-Tighten lower bolt
-Lower axle shaft to extend air spring fully
-Use DAS to fill air spring to ~5 Bar pressure
-Inspect air spring to ensure bag did not deform
-Lower vehicle onto wheels
-Start car (expect an error message on dash) and let vehicle raise to its proper height

FWIW, I found I had to perform a suspension height calibration after replacing my air springs. The car was sitting much too low with the rear lower than the front.
Front specs are 3.1 to 4.1 degrees (I incorrectly posted 2.9 to 3.4 in another post)
Rear specs are -0.9 to -1.5 degrees.
On my car I have the front set to 3.1 degrees and there is very little space between the tire and the fender. The rear is set to -1.2 degrees and there is about an inch of space between the tire and fender; I could reduce that if I calibrated the rear to -1.5 degrees to drop the rear of the car.

 

I have just replaced my front passenger strut on my 07 e63 and it was quite the learning adventure. In the process I ended up ripping the rubber on the upper ball joint and now need to replace it. Can I just replace the ball joint by the three bolts at the end of the control arm or do I need to replace the entire control arm?

Thanks.

 

Just the three bolts and use a ball joint removal tool.