So I did a really dumb thing yesterday. I was trying to chase down a front end creak that only happens when it is 28degC or hotter (just drove the car up from Florida so more relevant of an issue down there than up here in Toronto right now).

I figured I would give the two long subframe bolts and extra crank to see if they might be causing the creak. Tightened one...check. Tightened the other, crack. Busted. F me. The bolt I'm talking about is the long one that is accessed by putting an extension up from underneath the hole in the control arm to access the 17mm bolt head.

It's impossible to drill the threaded part out without removing the whole engine cradle/subframe. F me again. Considering just getting someone to weld the subframe to the frame as the car has got over 200k miles on it so if someone has to grind a weld off to remove the engine cradle before the car dies than it's not the end of the world.

So my question is this - is the top of that bolt visible/accessible anywhere so that I could drill it out or turn it from above? I've taken a look from the top but can't see much what with the fuse box, engine mount, air filter, etc in the way. I'm considering pulling all that stuff off to take a look but wondering if I'm wasting my time...

Really feeling like an idiot right about now.

 

I'm a little confused though. Seems like if you could get a socket on the bolt, you should be able to get a drill bit on it. Then it's just a matter of drilling a hole big enough to get a bolt remover in it. If that doesn't work, just drill and tap it for a larger bolt, and call it a day.

OTOH, I kind of like your welding idea, too... I guess if I had a welder and a car that wasn't going to be shown at too many car shows ;-) I'd consider doing the same. Sounds quicker and easier than drilling / removing / tapping the old bolt, IF you have easy access to a welder.

 

Well, normally that would make sense but these bolts are about 7" long with the last 1" being threaded (same as AC compressor bolt but bigger and rustier). The bolt broke at the threaded part so the broken bit I need access to is buried 6-7" up into the member itself. Does that make sense?

 

Ouch. Yeah, I guess the options would be to drop the subframe, or to weld it. Unless there's enough metal between the subframe and the broken bolt to tap some threads (can't imagine there is...).

 

It might be easiest to hole saw the frame, then remove the original thread insert, and then just build it back up with a regular nut if you like. when the subframe is reattached, then you can close up your hole if you feel the structure warrants it. Getting to the frame to hole saw it might involve a lot of hassle removing things you listed. You be the judge on that. You won't need to drill the bolt out, I don't think. I think you will find what it is threaded into is pretty flimsy and you will be relatively well satisfied to just dislodge it and throw it away. I could be wrong, though. I don't break off subframe bolts every day.

If you lay a little gusset plate up there and weld it, that may hold just fine, if you can find the sort of area you need to weld to.