oxygen sensor rusted into the cat

[sstein]

trying to change to Y-pipe

the oxygen sensor seems to be completely rusted into the cat

trying to spray to loosen it up, no luck yet

any other recommendations? or get a new oxygen sensor from beemer boneyard?
\
Thanks

hope this thread lives long enough to get a few responses.

[racurley]

Can you apply heat like with a torch to the bung where it screws in?

[sstein]

I have a heat gun, not a torch. Worth a try?

[sstein]

Was worried about damaging any delicate components within the O2 sensor, but I guess it gets a lot hotter with the engine running than my heating gun can heat it up to.

[racurley]

Certainly worth a try. I generally try the heat gun before the torch. Have you gotten the cat off already? Looking at the parts diagram, that O2 sensor looks hard to reach. Mine came without a cat from a PO.

I had a car that needed a new O2 sensor and ran into a problem getting it out. I couldn't get it hot enough. Took it to an exhaust place and they had to extract it and then weld in a new bung (screwy inny thing).

[sstein]

Thanks.
Yes the cat came off super easily, then I unplugged the O2 sensor from the right side of the bike so I could work on the whole thing more easily. rust remover - failure. Heat gun with BIG plumbers wrench - failure. In fact, the teeth of the wrench started to make grooves in the edges of the O2 sensor nut.
I plan to order from BBY. Only $30-40.
I did install the Y-pipe easily. and since it is more trimmed down, I can probably install the new O2 sensor without having to remove the Y-pipe.

At least that is the plan

[Sunbeemer]

They can be tough to remove...on cars I've soaked them in penetrating oil (I like the Zep brand) and tap on them with a small hammer just hard enough to work the oil into the threads. Then using a O2 socket wrench (has a long slit in it for the wire) I try to break it free while tapping. If that doesn't work then add more oil, tap some more and try twisting again. If that doesn't get it to budge, then it's time to heat and beat. Concentrate heat on the pipe fitting the sensor is screwed into. Tap on the base of the sensor from different angles while it's hot and then give the breaker-bar fitted socket some solid thumps with a dead-blow, nylon mallet to unscrew it. Once you get it broke free (not broke off:-(), you may have to rock it off and on, applying more off force than on force. Little by little you should be able to rock it off. They will not often unscrew easily after breaking loose, so you have to do this rocking off/on dance until you get them out... Once it's out, chase the threads with a tap if they are so galled up you can't get the new one to screw in, and remember to use Kopper-Kote or some such anti-sieze on the new sensor's threads or you'll be doing this again sometime?
Good luck, and let us know how it goes...

[sstein]

That's awesome Sunbeemer, thanks. I put in the order for the new sensor so the cat with the old sensor will sit in my shed until I get the time....
How exactly do you soak this part in penetrating oil? Obviously you wouldn't soak the whole cat in there.

[Sunbeemer]

Just spray all around the exposed sensor threads and tap on the flats of the sensor's nut and the collar it's screwed into -> repeatedly. Let it sit overnight if necessary and hit it again before you try to break it loose. You can keep doing this everyday for a week if you want, spray and tap, spray and tap, trying to work that penetrating fluid into the threads, but at some point you might have to try a more drastic measure...

...which is: heat the sensor and collar uniformly with a propane torch until its glowing a dull red then apply beeswax around the exposed threads next to the collar (carefully because it might ignite) and let it cool down. The wax should get drawn into the threads as it cools and the lubricated sensor should finally come loose. This technique will remove rusted exhaust manifold bolts/nuts, but I've never had to try it on an O2 sensor. Good luck!

[sstein]

Great, thanks.