Second O2 sensor removal questions

[boontis]

I've picked up a downpipe from Rock Auto and am planning to replace it as the existing one had the flange break apart from the pipe at the engine side connection (and getting it welded was going to cost way more than replacing with a new one).

I have a couple questions that I was hoping to ask as I've already hit a couple snags:

1 - the back bolts seemed to be between a 13 and 14mm - 13 wouldn't fit and 14 was sloppy - and easily rounded off. My plan is to cut them off. Any reason this could be bad? (the front 2 loosened off easily with a 14 that felt tight)

2 - the O2 sensor looks pretty rusty - I got a 22mm socket on it but it feels really loose. 7/8 feels the same. Should this be a 21mm?

3 - It's really tight in there - I was wondering if there is a connection point for the O2 wires so I could disconnect the whole thing, pull it off the truck, and fight with the O2 sensor on the bench. Anyone have any thoughts/experience with this?

I've already started hitting the O2 sensor with WD40 before I try as I need to salvage the sensor to put in the new downpipe.

Thanks in advance!

[smj999smj]

If what you have a through bolts with nuts, you can go ahead and cut them. You could also try an extractor socket, which is for use on rounded off nut and bolt heads. Here's a kit you can get for $20 at Lowe's:

https://www.lowes.com/pd/irwin-bolt-gri ... gLCMvD_BwE

BTW, the size "was" originally 14MM before it deteriorated some.

The O2 sensor is 13/16"...or, 21MM.

I'm not sure what you mean by "connection point," but there is a harness connector for the O2 sensor harness about 10" from the sensor; just follow the harness.

[boontis]

Perfect that answers my questions - thank you! I'll get the whole thing off and hopefully, with a straight angle, the O2 sensor will come out clean