Rattling from back of my X5

[rogerkiu]

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!