[stoweboarder720]

Hi all,

So in a bit of a panic. I was removing the rear bumper carrier (the metal bar, not the plastic bumper cover), and it is held in place by 6 18mm bolts. The bolts are welded into the chassis, and the nuts thread onto those bolts. One of the nuts became stuck and I tried to break it free but it ended up freeing the entire bolt instead. I'm not sure what to do here. Anyone heard of something similar? I'm assuming I need to have the bolt welded back into place.

Any help is appreciated!

[relative4]

What you're calling bolts are actually called studs. They are pressed into the frame rail flange, not welded. The repair needed depends on exactly what happened. Can you please post pics, preferably of both the back and the front.

[stoweboarder720]

Originally Posted by relative4

What you're calling bolts are actually called studs. They are pressed into the frame rail flange, not welded. The repair needed depends on exactly what happened. Can you please send pics, preferably of both the back and the front.

Thanks for the correction! I attached a couple photos, it's tough to get a shot of the back. You can see it in the background of the second photo. If it's impossible to tell what needs to be done without dropping the exhaust, I can do that and retake. It looks like it spun and broke up some of the under body coating on the backside.

[stoweboarder720]

Did some more digging. The tail trim body work, part number 2 in this diagram (https://www.realoem.com/bmw/enUS/sho...diagId=41_1703), the holes for the studs exist, I just can't find anything about the studs themselves. I want to say parts 10/11 in this diagram (https://www.realoem.com/bmw/enUS/sho...diagId=41_1673) are what the bumper carrier secures to, but when looking at the vehicle, it seems the piece of welded/bonded to the tail piece from the first diagram. The more I look into this, the more it seems like a very significant repair with extensive body work...

[relative4]

Yeah, can't see anything in the pic of the back.
I'd start by removing the old stud. Maybe a cutoff wheel will do the trick.
Seeing what's left of its head may indicate what needs to be done, if you can't get a pic of the back.
You can probably get a replacement stud at Napa, etc., but depending on what's damaged, you may just need to replace it with a bolt.

[stoweboarder720]

Originally Posted by relative4

Yeah, can't see anything in the pic of the back.
I'd start by removing the old stud. Maybe a cutoff wheel will do the trick.
Seeing what's left of its head may indicate what needs to be done, if you can't get a pic of the back.
You can probably get a replacement stud at Napa, etc., but depending on what's damaged, you may just need to replace it with a bolt.

Finally got the exhaust off. Here's some better ones! You can see where the seal has broken and the rivet is spinning behind.

[feuer]

Cut it off. Remove what you need to remove and reinstall only with the remaining 5 nuts. If that doesn’t make you at easy, put regular bolt, fasten it and smear silicone to prevent rust around the damaged seam sealant.

[mweisdorfer]

Originally Posted by stoweboarder720

Thanks for the correction! I attached a couple photos, it's tough to get a shot of the back. You can see it in the background of the second photo. If it's impossible to tell what needs to be done without dropping the exhaust, I can do that and retake. It looks like it spun and broke up some of the under body coating on the backside.

Is that part of the subframe?

[stoweboarder720]

Originally Posted by mweisdorfer

Is that part of the subframe?

Yes and no. So it's pressed and welded into a piece that makes up the rear most part of the subframe. Fortunately; the bottom screw is visible from the other side of the piece, but the top two are concealed within the frame rail. So if I broke one of the top ones, you'd likely have to cut off a piece of the rear subframe to get at the screw.

[avocet]

Try to cut off the nut and tap the stud out the back. Looks like you should be able to get a bolt in there, with a large washer or an oversize head. If you really want to get an oem look., try something like this, then seal it up:

[stoweboarder720]

Originally Posted by avocet

Try to cut off the nut and tap the stud out the back. Looks like you should be able to get a bolt in there, with a large washer or an oversize head. If you really want to get an oem look., try something like this, then seal it up:

Just ending up welding the existing one back in place and cleaning the threads. Looks great!

[avocet]

Oh, and by the way, spray the remaining studs with some penetrant and clean them up with a wire brush/wheel. And do that next time before you remove a nut from a crusty stud/bolt. A bit of antiseize or axle grease on threads at install isn't going to hurt either.

[mweisdorfer]

Originally Posted by stoweboarder720

Yes and no. So it's pressed and welded into a piece that makes up the rear most part of the subframe. Fortunately; the bottom screw is visible from the other side of the piece, but the top two are concealed within the frame rail. So if I broke one of the top ones, you'd likely have to cut off a piece of the rear subframe to get at the screw.

Well, it's a lot of work, but you fix it right you'd have to take the subframe out.

You can drill out the broken stud & put a bolt in from the other side.

Again, a sh@t ton of work, but it's the only way to fix it