Front air spring strut replacement

rogerkiu · #1 05-09-2012, 05:16 AM

Hi all! My X5 4.8is has a little problem with the front air spring strut. If it sits overnight, the right side front will drop around 4mm lower than left side, if it sits for 2 days, the right front side will drop even lower. I think the right side air spring is leaking very slowly. Now I am planning to replace both side air sping strut. I know it is DIYable and I have already had the manual for replacing front air spring strut. Only twe things confuse me, one is how to remove the front wheel arch and how to use the center ping of the strut to mark the poisition. Thanks for help!

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Turbo_Bimmer · #2 05-09-2012, 12:18 PM

Hi Roger.
I just did it on my 2005 4.8is last week end.

I know that BMW says to remove the wheel arch (liner), but I didn't. After the strut is unbolted from the knuckle and the sway bar unbolted, I removed 2 of the 3 top nuts then slowly the 3rd one with one arm while holding the strut in the wheel well. When loose, I slowly lowered the strut until it was supported on the suspension arm. I found that having a small piece of 2X4 wood over the suspension arm was easier and left more slack for manipulating the air hose. I then slowly unscrew the fitting until I could hear air going out, and let it bleed until empty.

For the centering pin, it will fit in only one way, so the strut will go back at the same position as it was before.

sockethead · #3 05-09-2012, 01:57 PM

Also, take a marker and outline each of the three nuts that hold the strut in on the top... One of my new struts came without the alignment pin on the top. If I hadn't marked it, I would of had to guess where it went.
This was one of the easiest strut replacements I've ever done...

rogerkiu · #4 05-09-2012, 10:32 PM

Thanks a lot for help!

Turbo Bimmer, do you mean just release the all screws on the wheel arch liner and there will be enough space to loose/tighten the air connection to the strut by lowering the strut? What do mean by 'having a small piece of 2X4 wood over the suspension arm was easier and left more slack for manipulating the air hose'? Can you explain more on this part? Thanks a lot!

rogerkiu · #5 05-10-2012, 03:22 AM

I see there are two black stuff on the top of the strut. Can anyone tell me which one is the center pin?

rogerkiu · #6 05-10-2012, 10:35 PM

Can anyone help?

Turbo_Bimmer · #7 05-11-2012, 06:58 AM

From the picture, it looks like the centering pin is the one on the right (cone shape). Your strut will go back at exactly the same place because of that pin, so don't remove or break it.

About the liner, I didn't even loosen it. There is about 3-4 inches of air hose coming out of the liner to the strut. That was enough for me to lower the strut about that (3-4'') to be able to unscrew the fitting. Since the air hose is short (with the liner in place) you cannot let the strut hang or drop by itself because you will put tension on the hose and kink it. That's why the strut needs to be supported at all time as long as the hose is not disconnected. Since holding the strut with one hand while removing the hose fitting with the other hand is not easy (strut is a bit heavy), I put the bottom of the strut on the suspension arm so it holds by itself. The 2X4 piece of wood was inserted between the bottom of the strut and the suspension arm to lift the strut a little bit and make more slack to the air hose (may be not required in your case).

If you are not comfortable working on the strut while it is up in the wheel well, then you will have to remove completly the liner, and unclip the small bracket holding the air hose to the body to give you more slack.

Something that you need to keep in mind, you must already know, but just in case, is to keep things clean and not kink the air hose.
Before unscrewing the air fitting, take a rag and wipe the hose, fitting and surroundings to remove any sand and dirt. You don 't want debris in the treads or in the system.

sockethead · #8 05-11-2012, 07:59 AM

Yep, the cone shaped thing is the alignment pin. I'd still take a sharpie and mark those three bolts in the picture.

I didn't touch the wheel well liner. I used a floor jack under the rotor to move the strut up and down as needed after unbolting. The air hose is hard to get to but it can be done pretty easily. If you use a floor jack, just be careful that you don't bend the backing plate behind the rotor. I got just the tip of the jack pad under the rotor and that worked great.