Help with o2 housing removal/install

[4g63tcrazy]

If its coming out really hard the threads are messed up. I've done it a million times. You can to sit there and work the bolt in and out over and over til it finally comes out. Otherwise you snap it and have bigger problems to deal with. Just work it loose a little and then tighten, then loosen a little more, ect. It will eventually work its way out.