Rattling from back of my X5
 

Hi all! I DIY replaced my rear shocks and rear air springs recently with brand new BMW OE parts. After replacement, a single rattling noise comes from the trunk every time when driving off after startup the car. No rattling noise when the car is running on the road after that single rattling noise right after starting up the car. I believe that the screws link the shocks to the swing arms are tightened to the specific torque requirement. I may check the top screws on the shocks and the screws connect the shocks to the body later. As required in the TIS, the tightening torque for the top screws is 27 nm and the screws to the body is 56 nm, the big lower screw is 127 nm.

What I need help here is that if my procedure of tightening the top screws and the screws to the body is proper. My procedure for tightening the screws is as below:

1. assemble everything onto the shocks (rubber tube, yellow stopper, support beating and other stuffs);
2. tighten the top screw by hand as tight as I can, as the support bearing turns when I am tightening the screw, so I am not quite sure if the tightening torque is met;
3. put the whole shock in place and tighten the big screw as tight as I can, I used my foot to push the screw until it could not turn anymore, so I think the screw is tighten to or even over the torque specific;
4. tighten the 3 screws that link to the body;
5. lower the car on its wheel and finished the job.

In the procedure above, do I have to tighten the top screw again after lowering the car on its wheel? If the rattling noise is caused by loose screws, I think the only possibility is the top screw.

Any idea from you guys? Thanks for help!

Is it possible that you are hearing noise from the drive-train, maybe u-joint or axle joint, and not the shocks. You might have stressed something in the drive-line when you had the car jacked up.

I only used the jack point and the rear sub-frame to support the car, so I don't think I stressed anything when jacking up the car. I think I will try to tighten the top screw of the shocks and the screws that connect to the body and see if it solve the rattling. If not, I will try to replace the rear swing bar link to see if it works. Thanks for comment.

Have you checked the upper boot lid stoppers, 2 round rubber pads on each side of the boot frame....sometimes they need adjusting. It could also be the air compressor bracket/frame...did you loosen it when you worked on the suspension?

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Air compressor bracket? Do you mean the triangle shape base that the compressor sits on? I will check it. The rubber stops of the boot lid have already been adjusted, but I will check it again. Thanks for comment.

Yes, the triangular frame that sits on top of the battery.

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