Broke front subframe bolt, suggestions

[Mike325]

I broke one of the four bolts that hold the front subframe on. I had broken this bolt last year and while checking it for tightness, it broke off, rather easily.
I am trying to take out the threaded insert for it and have some questions. First it looks like it is shapped like a capital H, but with a line going up through the middle of the H. The line through the middle is where the bolt goes. Is this part removeable and replaceable? Would I have to get a used one to put in?

It is eaither this or part out:( Any help would be appriciated.

[jlevie]

I can't see those bolts breaking unless the wrong grade bolt was used or they were mis-torqued. And I wouldn't replace the insert unless its threads were damaged past the point that cleaning with a tap could fix. Seems to my the first action should be to figure out why you've broken the same bolt twice.

[Mike325]

I was just checking to make sure it was still tight and I put maybe 15 ft pounds on it and it just snapped. All the threads are inside, just the head and the inch or so of non threaded shaft is what came out.

This hole was already drilled and re tapped again.

[Brew]

Are you trying to get the old, broken bolt out? Or repair the threads? You may be able to Heli-coil it.

If the old bolt is still broken-off in there, I've had good luck with left-handed drill bits. Use the correct size and it should come out like butter.

[Mike325]

Thanks for the help guys. It is far past the normal repairs that you have suggested. Right now it is best to part it out and start with a clean slate unfortunantly. Lots of new parts will be for sale soon;)

Thanks again.

[Aleman]

Well today I've entered the numb-skull club of people that have broken-off their front subframe mounting bolts. I snapped both bolts on the driver side, and now I believe I'm completely F'd. The right-side ones are still in-tact. Instead of attempting to loosen these bolts with a breaker bar, might I have better luck with an impact wrench and a torch? If so, I'll need to buy those tools.

As for getting the busted ones out, I've had horrible luck with reverse-threaded drill bit in the past, and I've had those square-shaped extractor bits break-off inside the hollowed-out bolts, too. Anyone know of a FOOL-PROOF way to get these things out, (assuming as the steps are correctly performed)?

[jlevie]

I've encountered broken front subframe bolts. What I do to get the stubs out is to use a 1/8" left hand twist drill silver soldered into a pilot that just fits into the hole in the subframe, with about an inch of the drill exposed. That ensures that the pilot hole will be centered on the stub. Then I switch a larger left hand twist drill, just a bit smaller than the minor diameter of the bolt. So far, the larger drill has spin out the remains after drilling part way into the stub. Once the stub is out I chase the threads and use new bolts (and grease).

The real trick here, or in other cases, is to ensure that the axis of the drill is aligned with the axis of the stub. If off center or at an angle bad things happen.