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Discussion Starter #1
just like the title states. my o2 sensor decided to go out and its the hardest one in the vehicle, you know the only located at at the firewall. no socket can fit correctly in the small space available. i have tried the o2 socket wrench and a regular wrench. i just get enough leverage to make anything happen. instead i went ahead and started to look into remove the Y pipe in hopes to remove the o2 sensor that way. well it seems that my bolts are some strange size. i dont own a metric or standard wrench that fits the strange bolt size. in the video below i used a 14mm wrench to show that it doesnt fit and neither does a 13mm or a standard sized wrench. what should i do?

 

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SEAHAWKS!!
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I dont remember the size wrench i used, but i was able to remove the ypipe bolts. Can you fit a wrench on the nut side? If so, use vise to clamp down on the bolt and do work. IIRC, thats probably what i did, after spraying PB blaster on it and letting it sit for a couple hours. It was a bitch to remove those bolts
 

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Discussion Starter #3
I dont remember the size wrench i used, but i was able to remove the ypipe bolts. Can you fit a wrench on the nut side? If so, use vise to clamp down on the bolt and do work. IIRC, thats probably what i did, after spraying PB blaster on it and letting it sit for a couple hours. It was a bitch to remove those bolts
i think a 14mm was able to fit but it seemed like its some weird size that is not in metric or standard. ill try that tomorrow while i drench more liquid wrench on header. im still stunned on the poor design with the o2 location. what size bolt and nut did you use once you removed it? i dont plan on using those bolts if i dont have to.
 

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95% sure the y pipe bolts are 14mm. They might be super coated in rust, so take a razor blade and scrape any residue off...
 

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It should be doable from the top with a o2 sensor socket, breaker bars and such. I did it once on a previous IS.

Removing the y-pipe... I did this couple months ago and I had to dremel every nuts and bolts, very dirty job, I don't recommend this if all you wanna do is replace the sensor. Also, don't forget the sensor will come off easier if it's warm and with PB Blaster.
 

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It should be doable from the top with a o2 sensor socket, breaker bars and such. I did it once on a previous IS.

Removing the y-pipe... I did this couple months ago and I had to dremel every nuts and bolts, very dirty job, I don't recommend this if all you wanna do is replace the sensor. Also, don't forget the sensor will come off easier if it's warm and with PB Blaster.
How were you able to do it from the top with an O2 socket and break bar? There is just no room. I am trying to replace mine but decided to regroup since I have been trying to take out the bitch for the last two hours. :frustrate I put liquid wrench on it and still no budge.

Does anybody know of any videos or photos?
 

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SEAHAWKS!!
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How were you able to do it from the top with an O2 socket and break bar? There is just no room. I am trying to replace mine but decided to regroup since I have been trying to take out the bitch for the last two hours. :frustrate I put liquid wrench on it and still no budge.

Does anybody know of any videos or photos?
Ha, I know the feeling. I used everything I had to try and remove it. The only leverage you have is from the top. I tried and tried until I gave up. I just let it be until I swapped out my header to catless header.

Oh, after removing the oem header, I couldn't get the o2 sensor out without stripping the threads. It was seized. There is a good chance yours are seized as well. You will have to remove the headers after unbolting the ypipe. BTW, is yours a manual or automatic? If its automatic, you will have to drop the header from the bottom, cus the transmission doesn't give enough room for the ypipe flanges to squeeze through. However, if you have a manual, no problems pulling from the top.

Good luck
 
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