Rear bumper guide bolt snapped, is it fixable?

[meen]

Howdy. The front tip of my rear bumper sagged a bit, so I removed the bumper and tried to take off the guides for replacement. Unfortunately, the front-most fasteners were very corroded and sheared off as soon as I applied pressure. The vehicle is a 2005 (post-facelift) 325i sedan.


This is the area of concern:






And here's the view from inside the wheel well. I tried unscrewing that nut but the bolt threads snapped off with it. Note that there was also a washer between the nut and plastic guide tip.



Here's a close up of the base the bolt threads snapped off of:



Looking at the relevant realoem page:



It looks like parts 12 (54218251229) and 13 (07119905543) are the nut and bolt in the wheel well used to hold that end of the guide rail. My guess is that the head of part 12 is welded or otherwise permanently affixed to the body panel itself. And it looks like there's some kind of thin metal disc stamped onto/around part 12. I think what I'm going to do is grind off what's left of the bolt, then epoxy or jb weld a replacement part 12 in the same spot and fasten the guide rail to that.


So what I'm asking is, do you think I'm right that 12 and 13 are the parts in question, and do you think grinding/gluing is the right way to go?


I tried looking this up and I only found mention of this particular issue at e46zone, which reached no conclusion.

[myblackcar]

Spray PB blaster or some penetrating fluid onto the broken bolt. Let it soak overnight.

Get a drill bit that is narrower than the bolt. Drill into the center of the broken bolt as best you can. Get as much of the old bolt material out without damaging the original threads on the bodywork.

At some point, it should be enough for you to remove the old material and clean the threads with a tap.

The other option is to drill a larger hole and insert new threads. I use EZ Loks because they are more durable than Helicoils and much cheaper and does not use proprietary tools like Timeserts.

https://www.amazon.com/Z-Externally-...ded+insert+m10

[meen]

I think we're interpreting this differently. I think you're saying a bolt is screwed through the guide into threads in the body panel, as in this image, and the bolt snapped as I unscrewed it, and now I have to extract the rest of the bolt from the panel so i can clear the threads to insert a new bolt.



I don't think that's the case. I don't think there's even enough depth in the body panel to screw in any kind of bolt (or the threaded insert you suggested). I think what's going on is this:



That flat square face on bolt 12 is welded/glued to the body panel, and while I was unscrewing nut 13, most of bolt 12's threads snapped off with the nut. If I'm right, I can't simply remove bolt 12 from the panel, so I'm thinking the safest and least-damaging way to go about it would be just to grind off the rest of the threads from bolt 12, and glue the new bolt 12 over the base of the old one. This would force the tip of the bumper guide to sit a little farther out, but there are 6 other fasteners holding the guide in place so I think it'll work.

Another thing to note, I mentioned a thin stamped metal disc over the base of bolt 12. Now that I look at it again, I think there is no metal disc. I think the large metal circle is just the bare inside of the body panel, and bolt 12 is welded directly to it. And the warped metal around the base of the bolt is the residue from welding. If that's the case then maybe I'll just grind a bit further until most of the old bolt 12 is out. Though I would need to keep the base flat enough to keep the new bolt 12 pointed in the right direction, so I still might only grind down the threads.



Let me know if you think I misunderstood you or any of this.

[dworthy]

That is a stud welded to the body, and it would be the stud that snapped off, not a bolt. So if you want to keep it OEM, then grind down what is left of the stud, and weld your "#12" back in it's place.

What I have learned about those studs is you have to use some anti-seize if you ever remove the nut off of them again, otherwise next time it will snap off.