So you couldn't get the bolt out and you had to have it machined out.

This is a crappy picture but it shows the threads were slightly damaged when the broken bolt was machined out.

Here we are re-threading the hole. There was enough meat left on the original threads to re-use. Make sure you use some type of cutting oil or lubricant when re-threading holes.

Now run the bolt in the hole to make sure it goes in and comes out easily.

Now you can install the Megan O2 housing you just purchased from us ;)

If the threads were seriously damaged to the point where it is un-repairable. Drill out the threads and use a nut and bolt to secure the o2 housing