Safe to Heli-coil AC bracket to cylinder head?

[Olypen Guy]

I've got a 1992 k2500 with the 5.7 TBI. Previous owner at some point broke both the stud and bolt that hold the aluminum AC bracket to the cylinder head. I was able to retrieve one from the head, but the other, I've now broken two easy outs into it. There's not enough left to drill it any bigger and still save the threads. So now I'm wondering if there's enough room for drilling it all out and placing a heli-coil in there. I know one of the intake bolts must be kind of close, but I'm not sure where coolant and oil journals go in there. Right now, swapping out the heads is not an option for me. I don't have the money nor do I have the time.

I've tried penetrating oil, heat, you name it. It's recessed about 1/8 of an inch into the head, and I don't currently have access to a welder, so welding a nut on to it is also not an option.

Has anyone done a heli-coil?


The red circle is the one I'm having issues with. Green circle came out fine. Blue circle is the intake bolt I'm slightly concerned about. Then of course, the hidden from outside view, coolant and oil journals.

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[GarrettGmc]

If the easy outs dnt work then I'd drill it out, just make sure it's dead center then you can heli coil it. I did one of my spark plugs while back when it got stripped and went easy. Also had to use the easy out for broken exhaust manifold to head bolt. Just heated it up a bit and used some oil and it came out pretty easy

 

[biggbiker]

if you can centerpunch it on center, try a left handed drill bit ,spinning backwards. if the bit bites it will unscrew itself. helicoils work great.

 

[skylark]

Hit it with heat. While it is hot hit it with a can of "dust off"(or similar) that is turned upside down. The can will emit an extremely cold vapor. This rapid cooling with an easy out ready to go works miracles.

 

[GarrettGmc]

Hit it with heat. While it is hot hit it with a can of "dust off"(or similar) that is turned upside down. The can will emit an extremely cold vapor. This rapid cooling with an easy out ready to go works miracles.

Never heard this method, ill have to try it sometime

 

[Hipster]

Your not to be able to drill a easy-out out of it. You'll end up drilling along side of it. Not sure how you're going to solve that. maybe take a punch and tap on it and get it loose. It's really going to need edm'd. The method I use is to center punch the broken bolt, start drilling with a 1/16 or1/8 bit paying attention to depth and keep stepping the bit size until you get to the size bit for the tap. Tap it. 9 times out of 10 it will tap clean and your good to go. If not then go to the heli-coil. I actually prefer Time-serts or thread-serts over heli-coils. I quit messing with easy outs after I broke a couple.

 

[c1500deathtrap]

If you are feeling brave, get some long jumper cable and a battery. Set the battery downwind, ground battery to head, clamp a bolt in the jumper cable. Then press bolt end to the broken stud. if all works well you have a bolt welded to your busted stud.As a plus its all hot n toasty so hit it with a can of dust off to shrink the stud and crank it out!. *result may vary **safety certainly not garunteed

 

[90halfton]

Drive it to a welding / machine shop. They'd probably well a nut on for next to nothing. Worth a shot to call and ask

 

[90halfton]

If you are feeling brave, get some long jumper cable and a battery. Set the battery downwind, ground battery to head, clamp a bolt in the jumper cable. Then press bolt end to the broken stud. if all works well you have a bolt welded to your busted stud.As a plus its all hot n toasty so hit it with a can of dust off to shrink the stud and crank it out!. *result may vary **safety certainly not garunteed

I cannot wait til I have an excuse to try this lol.

 

[kennythewelder]

I work as a welder @ a machine shop. We extract bolts like this all the time. We weld a flat washer to the stud, then a nut to the flat washer. We do this with a TIG welder, and weld it with 630 inconel. In your case, I would fill weld the broken stud with 630, so I could tie in the flat washer to the stud. Then weld the flat washer to that 630 build up on the stud, then a nut to that washer. Let it cool for about 10 mins, and unscrew it. With the broken off easy out in there, you will never drill that out because it is harder than the drill bit. As mentioned above, find a machine shop with a good welder that can do this for you. The biggest issue will be seeing to weld in there. You have to be able to see it to weld it, and this means with a welding hood on. As for a heli coil , you still have to get the stud out of there, but if you mess up the threads, then yes that will work. Also, you will want to chase the threads with a tap before you put new bolts in.