Took O2 sensor out today, took a lot of persuasion to finally back it out. Even had to heat up the tube to get it to start. Also used PB Blaster & let it soak for 1/2 hour first. Well the threads are trashed now, sort of flat. Any one knw where to find a 11/16x16 tap to clean them up? They might not clean up enuff to grab the O2 threads. What can be done to fix this if tapping won't work?
TIA!!!
87 5.0L, completely stock truck

 

If you retap and the threads still don't hold, you have a few choices. You can enlarge, retap, and use a helicoil. You can weld the bung closed and redrill and retap. You can weld the bung closed and weld on a new bung.

Helicoil is probably the most DIY/driveway method. Harbor Freight and many other places have the helicoils and taps you need. It's possible an autostore will have the helicoil too. YOu're not the first guy to suffer o2 bung thread problems.

 

you might have to try a heli coil for it, or cut the old one off and reweld a new bung on it.

 

any good auto parts store will have tap. try napa

 

Yea, saw a 18mmx1.5 that will do it at @utozone this evening. Hopefully there is enuff metal left in the hole to hold the new sensor. BTW, the one I took out WAS the original from the factory! This new sensor should really help the truck better since there is 172k on it.

 

Bought the thread chaser this am & took my time running it in & out till it would run all the way in easily. Used some anti-sieze on the new one prior to installing. Started the truck & noticed a hugh difference right away. I had also done lots of emmissions components work as well. Drove the truck a few miles & am extremely pleased with the results. It's gotta get better milage considering how much better & smoother it runs!
Thanks for the help everyone.

 

great job. now you can lend tread chaser to other forum members.

 

The thread chaser was only $6.50 at @utozone. Would cost more to round trip ship than it is worth. This chaser is actually dual purpose/ended. It has 18x1.5 on one end & 14mm on other end. It's made by OEM Industrial, part # 25124. It says it's a spark plug hole thread chaser & you use with a 13/16" deep well socket, which is a small spark plug socket.
Drove truck to fill up rear tank & will check gas milage at next fill-up. But I can already tell it's gonna be better just because it runs so much better in every aspect!