Bit that fell off? I presume you mean the back side of the hinge around the pin: negative. It probably doesn't hurt to have it. On two of my repairs the hinge only cracked, I caught it before it broke and of course I left the part and wrapped the steel zip tie around it.

I might have a video of what happens if you only used a nylon zip or only one wrap of steel: the hinge pulls open at least 1mm each operation so I wouldn't trust it long term. With the two steel wraps no motion at all it's a solid fix.

I haven't ever had to replace one done with the steel repair (some are going on 3-4 years now). I forget but I think I put a shim under the steel to snug it tight.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)