Morning (again).

So - studs are pretty rusted/worn - bought all new studs.

Trying to get the old ones out - one came out fine, the other 3 sheared off, i am not sure how to continue... Drilled the 3 with the biggest HSS bit i own, slightly smalled than the correct diameter - how the heck do i get the stud metal out of the threads?

Cheers in advance

 

a stud extractor ??

 

I used this one to remove them, one came out, the other 3 sheered off at the base.

 

There are bolt extractors such as 'easy out' that self tap left handed into a hole drilled into the sheared off stud. Even with those, it helps to do some heating and cooling. generous soaking with penetrating oil, and a few well judged blows with hammer and punch. And if all else fails, find a big enough drill and take the lot out using the manifold as a template to guide the drill.

 

Easy out didn’t work, so plan B - drilled and tapped.

Tadaaahhh!