what is it with the rearmost bolts snapping the heads off. i got "lucky" and only broke one, the other must have been twisted off during assembly. i get the one i snapped off out fairly easily. the other was snapped offalmost flush with the mating surface. i spent a lot of time carefully drilling it out, making sure it was dead center.i went to home depot and got and extractor set.i tapped the extractor in the hole and began to turn it. it was creaking like it was about to come loose. i gave it one more tap, and the friggin extractor snapped off inside the bolt. chinese piece of ****. the bits i used to drill out the bolt arent even making a mark on the broken extractor. im going to have the heads pressure tested for cracks. i dont know how this is done. does the manifold bolt need to be removed for pressure testing? anyone think i can drill out that broken bit of extractor, what kind of bit do i need? its been without that bolt since ive owned it, i guess it could go without. but id really like to get it out of there. thanks for any input.

 

Go to the hardware store and ask them what bit you need, I would drill and tap for a slightly bigger bolt. I did that on the crank bolt that I broke and couldn't get out.

 

i was wondering if i could go a size larger. cool, thanks for the reply. anyone know about the pressure testing, how its done?do i need to clean the heads up? thanks again

 

one more question, say one of the heads is cracked, is it wise to replace just one head?

 

after doing a search i see where i went wrong, not drilling the hole out large enough.lesson learned.

 

GM and their cheap *** OEM manifold bolts. I broke 3 when I did my header install. I was able to get one out my self. One was tapped and had a stud put in. and one still has the broken bolt still in the head. No exhaust leaks but wish I could get them all bolted up.

 

I've never had a problem with stock bolts. still using them

 

Seriously!!!??!?? You must have the magic touch! I haven't had ANY luck with them!

 

Antiseeze and head studs....could get them out of the head with my fingers

 

Same here. But I did give them a good soaking for a week with Kroil penetrating lube before the header install. I could have broken them loose with two fingers on the wrench.