syncro

Hi all, I've got an '02 ML500 and was doing the drive shaft bearing. Unfortunately the bolt heads securing the bearing support to the frame broke off due to corrosion. I'm guessing my only option at this point is to try and carefully drill out the bolts? What makes it a giant PITA is the ends of the bolts have a notch cut into them which will make them even more difficult drill out.

Suggestions or words of encouragement are appreciated.

Chevota

Pix would be nice, but my guess is yes, drill them out.
Is it safe to assume there is a nut on the back side that it welded to the frame? If so, it may be easier to bust or cut that off? This is where pix would be handy for me/us. Depending on the mount you may also be able to drill new holes next to the existing for new bolts. Too bad I don't have a pix
I had one of those cars but never looked at that part, so I'm basing my opinions on what I'd expect it to look like, but I have no doubt it can be fixed fairly easily.

syncro

No pics available right now, but I can get some - here's a drawing instead. The drive shaft bearing mount gets bolted to the top of the crossmember, and the nut inside the crossmember is a welded on flange, not an actual nut. Access is difficult because is only a small hole that gives some access. I was given one idea of putting a double nut on the end of the bolt and using that to try and twist out the remainder of the bolt, but I'm not sure if the hole is big enough to fit a 16mm socket into to grab the M10 nuts that would go on the bolt. The problem with drilling out the bolt is that the bolt is a self locking type that has a v-notch at the end, so I'd need to grind down the end of the bolt first which can't be done due to the limited access. At this point I'm not willing to cut a larger hole in the cross member for better access. I'm hoping someone who has run into this issue before can chime in on how they fixed it.

Chevota

Ouch...
So the bolt head is accessed on top, and the bolt heads broke off, correct? Any meat left you can grab with Vice Grips? Probably not since they tend to break at the nut.
And I assume the cross member is welded to the frame and no handy removable panel in the floor to access it? I suppose if they designed the bolt setup like that then they didn't give a rats a$$ about access.

Crap. Well, I suppose I'd just weld the new mount on. It's not like you'll ever need to change it again, and if you do you can grind it off.
Or I'd blow torch the bolts out. Maybe more options when I see pix, but so far that's what I'm thinkin.