Again, BMW and their plastic parts are not too sturdy. I remember having to replace my interior door handle pull in my E30 325i because the handle's plastic material would split and it would be hard to open the door.
Well, my 2001 X5 3.0i was ordered with rear climate package which included rear sunshade for the rear side windows. You pull up the shades and the shades stay up by being attached to two plastic hooks.
Over time, heat & vibration will destroy the plastic hooks and it will form a crack and then it breaks apart.
Apparently, since 2001, BMW redesigned the hooks to be more sturdier.
Part# 51-16-7-155-428 HOOK SET, List $2.60
It comes in a set of 4 hooks.
There is one phillips screw that holds the hook in place.
Step 1: Pry open the thin plastic cover of the hook & expose the phillips screw (if you have an old-style hook, you'll also have some springs in there--remove them and don't worry, you will NOT need them for the new hook)
Step 2: Remove the screw & washer. The plastic hook will still be attached to the metal frame of the upper part of the door. Just wiggle out the the old hook.
Step 3: As you can see on the top of the new hook, you'll have to wiggle in the new hook into the opening of the upper metal frame of the door
Step 4: Put back the screw & washer and as you tighten, make sure the hook is aligned correctly. Then close the thin plastic cover of the hook and VOILA, you have a new upgraded, sturdier hook.
I noticed that the shades clip on the new hook at a higher level than the older hook and so you should replace the new hooks in pairs if you have the older style hooks.
In the picture, you'll see the "older style" hook looks thinner and it is the hook closer to you in the pic.
Also, you can see the pictures of the new hook.