Sheared bolt.

[caltanian]

So yep, as the title says, there's a sheared bolt on my 240.

One of the front diff carrier bolts, gone. Easy out failed, and it seems made it worse (caught threads as well. No go.

So what can be done here? I turn to you fellow z people, to tell me what to do.

Much appreciated.

[pjoe]

If you can drill the bolt out, you can rethread it with a tap. You may have to use a slightly larger tap and bolt. If its broke off flush you could try using a dremel to cut a slot in it then use alot of heat and a big flat head screw driver to get it out but a bolt that size may be hard to get out with a screw driver. Lots of heat works wonders though. If you do drill it be real sure to use punch exactly in center of bolt if possible.

Brian

[Zed Head]

Not even sure what you mean by "front diff carrier bolt". Can you add some description?

If you tried an EZ-Out then you must have already drilled a hole in the remainder of the bolt. How do you "catch threads" if the bolt is still in there? Why would that make it worse?

Sorry, but your post is not real clear on what exactly you're trying to fix. If you do have a broken bolt with a hole already drilled in it, that an EZ-Out will get started in, then I would heat it up with a torch, spray some PB Blaster or Liquid wrench on it, let it cool, spray some more penetrant, then heat the area around it again while trying to twist it out.

[caltanian]

Sorry for not being as clear as possible.

The member that holds the rear diff bushing on it, as well as acts as the forward hold of the rear control arms is the part i'm talking about. One of the four bolts that holds that up and on has sheared off.

I'm likely to go forward with the drill it all the way out, and re-tap the hole and see if that can't save it for me.

The first attempt to remove it with pb blaster, and heat, and a easy out only led to the drill getting a little off kilter, and running through a thread. Hence my caught a thread comment.

[SteveJ]

Suggestion - (Assuming this bolt isn't reverse threaded...) When you go to drill it out, use a left-handed drill bit. It may catch and turn the broken bolt, allowing it to come out.

[Zed Head]

Bummer. So you already have an off-center hole drilled. That bolt is fairly large in diameter. You might be able to get a small rat-tail file in there and try to re-center it.

The bolt is the standard right-hand thread but if you're already in to the threads on one side, it's probably too late to try the left-hand drill. You'll probably have to work most of it out by hand until you can get a tap in there. Tedious. A tap will drag the small pieces out once they're thin enough. I think that bolt is fine thread though, so a tap might be difficult to find and probably expensive.

I don't think that you can reach the back side from the top either. You have a dilemma.

[olzed]

Can you work at the fat side of the bolt,with a drill, say around 3/16 inch. Break the drill off short, so it does'nt bend so easy,and resharpen it. Then work at the side with all the meat left, using the drill at an angle. Could be tedious, but might work. Put a centre punch mark if you can.

You can also buy file drills I believe, although I have never used one. If you have cut into the threads on one side, you may be able to use a very small cold chisel to collapse the other side and tap it loose.

2c from me.

[pjoe]

Just thought of this...If you havent installed a R/t mount yet you could do it the same way Zsondabrain did it. This way you dont even need that bolt anyway because I believe the R/T mount he used with the GM mount eliminates that crossmember. I might be wrong but may be worth looking into if all other attemps to fix it fail. Good luck.

Brian

[pjoe]

Hope this works.

http://www.classiczcars.com/forums/showthread.php?39172-R-T-Mount-Group-Buy-2nd-Batch-Who-s-in

[FastWoman]

I've had luck using the approach Olzed suggests. You can drive an awl between the bolt and the threads where the metal on the bolt is thin (i.e. where you started drilling into the threads). This will mess up the threads, but it will collapse the bolt in on itself. Once you've partially collapsed the bolt, you stand a chance of working it loose and extracting it from the hole. Once the offending metal is removed, you can clean up the threads with a tap, and they're not too much worse for the wear. Of course this works better with a well centered hole (and thin walls all around), but it also works with off center ones.

[beermanpete]

How far off center is the new hole you drilled from the true center of the original thread? If it is not too far off just drill it out with the correct tap drill and re-thread the hole. If this is 1 of the 4 screws that hold the cross-member in you should be ok with just the 1 off center a little bit.

[grantf]

I have a sheared off bolt also. I will not use an easy out, I will first try a reverse hand drill, I will try peening counter clockwise, use heat and a penetrating lube. I may also weld a nut to the top of the stud. If you do drill and the tapping does not go well you could tap it out larger and use a helicoil.