Broken bolts exhaust manifold - LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums
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post #1 of 2 (permalink) Old 08-15-2019, 08:47 PM Thread Starter
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Broken bolts exhaust manifold

Had a bad exhaust leak due to two broken bolts drivers side. The last rear bolt and the third to the last bolt. Tried drilling the 3rd to the last bolt and using a left handed drill. Used pb blaster and nothing. Getting frustrated and dont know what to do. Was looking into just breaking the bolt bu drilling then re- threading the hole. Any suggestions. Thanks!!
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post #2 of 2 (permalink) Old 08-16-2019, 07:29 AM
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Did you remove the exhaust manifold to work on the broken bolt? This is necessary to properly get to the bolt. You say you used pb blaster. But did you do it properly?

The proper way to get a rusted bolt out is to spray it down, then tap it lightly with a hammer to set up a vibration. On severely rusted bolts like yours, you need to repeat the spray down & tap procedure every 3 to 4 hours. And do this over a 3 day period. Then your bolt should be ready for removal.

If bolt still won't come out, try this.

Drilling the bolt must be done carefully as you want the hole dead center in the bolt. You drill out until only a thin shell is left of the bolt. But not drilling into the bolt hole. And on the rea bolts, an angle drill is probably needed to get a good stright drill down.

You then use a very small screwdriver & small hammer to cave the outer shell of the bolt, inward. Be careful as you don't want to mess up the threads of the bolt hole. When enough of the original bolt has been caved in, you should be able to turn the bolt and get it out.

And, welcome to the forum.

Last edited by cocobolo95; 08-16-2019 at 07:31 AM.
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