2G Subframe bolt broke in frame.

[John Miller]

Hello my fellow DSM addicts!

I recently dropped my subframe to do solid bushings. Upon reinstallation, I was torqueing down the passenger side bolt and it suddenly stripped out. Upon further investigation it looks the previous owner broke the bolt as there is part of the bolt still within the frame. Both subframe bolts were missing when I bought the car (shell) so I just assumed the person used it as parts. The bolt stud is about 1-2 inches within the frame and a bolt will only thread in about a half an inch. I tried drilling and tapping it again, but that didn't seem to work. So I only really know of two options. 1. See if I can drill it out all the way and tap it to a 1.5 or such. 2. Remove the subframe again and weld in a stud like the other subframe studs. Let me know what would be best or if you have any other ideas!!

Thanks

 

[spyderdrifter]

Welding in a new stud would probably be your best option. I had a similar issue with my front subframe where my compression arm bolt sheared off. I broke an extractor in it while trying to remove it, and heat didn't help. I ended up just getting a new subframe. I was lucky it wasn't in the unibody though.

 

[John Miller]

Welding in a new stud would probably be your best option. I had a similar issue with my front subframe where my compression arm bolt sheared off. I broke an extractor in it while trying to remove it, and heat didn't help. I ended up just getting a new subframe. I was lucky it wasn't in the unibody though.

That's what I'm thinking to, the only issue is that there can't really be an exposed weld since the subframe and unibody have to be flush like the other side.

 

[spyderdrifter]

Yeah, but if the weld penetrates deep enough, you can grind the outside of it flush so the subframe seats properly. The only real issue is strength.

 

[John Miller]

Yeah, but if the weld penetrates deep enough, you can grind the outside of it flush so the subframe seats properly. The only real issue is strength.

That is an other issue, if I wanted to create a gap for the weld I would have to drill out the hole in the unibody. I can't undersize the stud because there would be slop between the stud and subframe bushing. I don't remember exactly what they are torqued to, but it is prolly around 90ish foot lbs. I guess I could try torqueing down something to just the stud to see if it holds.

 

[1999RSfwd]

If you decided to weld a stud on, could you countersink the hole in the unibody?
I would think that would allow for more surface area and penetration for the weld.

 

[John Miller]

If you decided to weld a stud on, could you countersink the hole in the unibody?
I would think that would allow for more surface area and penetration for the weld.

I probably could, I just dont know how much I can open up the hole without sacrificing structural integrity.