Cant get O2 sensor back in!! What size tread tap ??

[gregpro50]

Cant get O2 sensor back in!! What size thread tap ??

I pulled the old O2 sensors out of my H-pipe and they came out real hard. Who ever did it last time never used anti-seize. Now I cant get one of the new ones back in because the threads are boogered up. Does anyone know what size thread tap I am going to need ?? I have to go buy one...

 

[Rick 91GT]

Beleive it is a 18mm thread

 

[46defense]

I think it is a M18x1.25, but I'm not positive. I have one at work, so I can check for sure tomorrow. If you want to check for yourself, measure the distance from the top of one thread on your sensor, to the top of another. That is what is known as the pitch. That is what the 1.25 stands for.
1 mm = approximately .040 (which is pronounced, 40 thousandths)
So 1.25 would be about .050, and 1.5 would be about .060
I know that these differences are small, so try measuring as many threads as you can and it will be easier. For example, 5 threads at a 1mm pitch would be
.04 x 5= .200 (just a tad over 3/16")
5 threads at a 1.25 pitch would .05 x 5= .25 (or 1/4")
5 threads at a 1.5 pitch would be .06 x 5= .300 (just a tad under 5/16")
Hope this helps, and makes sense. Just remember, you asked! LOL!

 

[gregpro50]

I am going to try to figure it out tomorrow. If its not too much trouble can you check and see for me? I hope Sears sells something like that. I have a tool to measure the thread, I just dont know if I will be able to find a tap that is big enough. That O2 opening is a pretty big one.

 

[Rick 91GT]

if you can not find it locally, which will be hard

www.mcmastercarr.com you'll have it next day

 

[ratrapp]

just buy a double sided spark plug tap.it's the same size.

 

[gregpro50]

Arent the spark plugs alot smaller than the O2 sensor ?

 

[BlackFox5.0]

It's 18mm x 1.5

 

[ALMOSTFINISHED]

just buy a double sided spark plug tap.it's the same size.

I second that. The opposing side is the right size for the 02 bung, (haha i like saying bung)

Nick

 

[gregpro50]

IT WORKED !!! After a night of swearing and throwing tools I am so happy right now I could do cartwheels. The $5 spark-plug thread chaser worked perfect and it was probably something I should have in my toolbox anyway. Its interesting that the best tool that I have is my computer and everyone that makes up stangnet. THANKS GUYS !!