I took the housing off of my O2 sensor to clean it (2001 Vmax 225 EFI) and the first thing I noticed was a bolt head and washer sitting at the bottom of the housing.



It was easy to see where it came from and I also noticed that there was quite a bit of black gunk everywhere in there and that is was even running down the side of the engine (see arrow).



Is it normal for it to be this dirty inside these housings? Will I need to replace anything when I remove the piece to replace the broken bolt? Can I just go to a hardware store and match this bolt?

I also found out the hard way that all Sensor sockets are not created equal. the one I bought is too thick to fit over the O2 sensor on the side near the broken bolt.



I guess I'll look for one with thinner walls or I'll just grind a little off the sides of the one I have. This also made me wonder if this broken bolt was stressed by whoever installed the O2 sensor originally because of a tight fitting socket