Tool for Stripped O2 Sensor

[emerydc8]

Does anyone know of an extraction tool for a stripped oxygen sensor? I am working on an Audi and the passenger bank rear O2 sensor has likely never been replaced. Being a Michigan car its whole life, the sensor has seemingly decided to weld itself to the exhaust manifold. I snapped a 3/8" drive extension and broke a 1/2" drive socket trying to get it off. With a stronger-walled socket, I managed to strip the outside of the sensor.

Before I take a drill to this I thought I'd see if anyone has seen anything on the market for a situation like this. I have bold extractors, but they are for much smaller bolts -- nothing in the 22mm range.

The good part is I have a clear shot to the sensor from above but I'd rather not drill and risk damaging the threads if I can avoid it. I'd probably drill it out to the point that I can hammer a triple-square or Torx into the center and see if I can break it loose from there. Thanks in advance.

 

[gerryvz]

I’d try the XZN as you say and see id that works. Before that, Vise Grip if possible? Definitely soak it for a few hours in Kroil or other quality penetrating oil.

 

[emerydc8]

Thanks Gerry. I did soak it in PB Blaster but due to the encasement around the manifold, it's hard to tell whether any of it actually made its way to the threads. I don't have the room for vice grips. Looks like I need to order a thread chaser too.

 

[nocfn]

how about getting it hot by running the vehicle for 10 minutes then attempting to crack it loose.

 

[IslandMon]

I was able to remove one that was stuck by alternating between MAP gas torch and PB blaster a few times, in a well ventilated area of course.

 

[emerydc8]

how about getting it hot by running the vehicle for 10 minutes then attempting to crack it loose.

The car had already been run for ten minutes prior to my disconnecting all the electrical plugs. Toward that idea, I might take a blow torch to the bung where the threads plug in. I just ordered the larger size bolt extraction tools from Amazon and the two rear Bosch O2 sensors. i’ll probably have this stripped sensor out by tomorrow but I suspect the driver‘s side will be just as bad.

 

[emerydc8]

I was able to remove one that was stuck by alternating between MAP gas torch and PB blaster a few times, in a well ventilated area of course.

I tried hitting it with MAP, then PB Blaster, then MAP. I held the MAP until the metal was glowing. This thing is a bastard! I cut the O2 sensor off at the base with a Dremel and was able to hammer a triple-square bit into the center. Using a 1/2" breaker bar, all that happened was more stripping. I tried hammering a Torx bit in there too, but it stripped as well. Now, I'm in between sizes, so neither bit will grab the inside of the sensor.

I have a bolt extraction kit coming tomorrow that goes around the perimeter of the sensor. I tired drilling the inside of the sensor out with a 1/4" x 12" drill. I don't know what kind of metal this thing is made of but the drill barely ,made a dent. If the bolt extraction tool doesn't work, I guess I'll have to start with smaller titanium drill bits and work my way up. There's no room to get the drill down there so the bit has to be a foot long to reach it. I've never seen something seized up like this.

 

[JC220]

I tried hitting it with MAP, then PB Blaster, then MAP. I held the MAP until the metal was glowing. This thing is a bastard! I cut the O2 sensor off at the base with a Dremel and was able to hammer a triple-square bit into the center. Using a 1/2" breaker bar, all that happened was more stripping. I tried hammering a Torx bit in there too, but it stripped as well. Now, I'm in between sizes, so neither bit will grab the inside of the sensor.

I have a bolt extraction kit coming tomorrow that goes around the perimeter of the sensor. I tired drilling the inside of the sensor out with a 1/4" x 12" drill. I don't know what kind of metal this thing is made of but the drill barely ,made a dent. If the bolt extraction tool doesn't work, I guess I'll have to start with smaller titanium drill bits and work my way up. There's no room to get the drill down there so the bit has to be a foot long to reach it. I've never seen something seized up like this.

I have seen lots of seized items like this! Usually I bite the bullet and remove the exhuast for 02 sensor removal on really old sensors due to bitter past experiences.

What I normally do is: Cut off top of sensor. Get a tight fitting impact socket and impact ready. Use MAP to heat the bung as much as possible, hit with some oil and 6 point impact socket. Usually that gets them. Then you will need a thread chaser tool for 02 sensors to clean up old threads.

If this does not work for any reason then I weld on a large nut so it is glowing red hot and gets proper purchase. Thread extractors will not work on something like this for me anyway especially in situ.....

 

[emerydc8]

I have seen lots of seized items like this! Usually I bite the bullet and remove the exhuast for 02 sensor removal on really old sensors due to bitter past experiences.

I didn't want to hear that, but you may be right. Based on the lack of space in the engine bay, something tells me that it won't be as easy as the W124/M119 manifold removal. I have an air impact gun but I hadn't thought of using it. I'm glad you mentioned it. I'll try that with the bolt extractor first before I completely round off the sensor.

This rear O2 sensor has nothing to do with the operation of the engine, so it likely has never been changed in 19 years.. All it does is compare with the front and set off a code when the cat starts to lose efficiency. Actually, the reason for removing it is that I'm adding a mini-O2 sensor of sorts. O2 Simulators

If I can't get it out, I have the option of registering it at a relative's house where they don't have emissions at all. Thanks for the suggestion!

 

[JC220]

I didn't want to hear that, but you may be right. Based on the lack of space in the engine bay, something tells me that it won't be as easy as the W124/M119 manifold removal. I have an air impact gun but I hadn't thought of using it. I'm glad you mentioned it. I'll try that with the bolt extractor first before I completely round off the sensor.

This rear O2 sensor has nothing to do with the operation of the engine, so it likely has never been changed in 19 years.. All it does is compare with the front and set off a code when the cat starts to lose efficiency. Actually, the reason for removing it is that I'm adding a mini-O2 sensor of sorts. O2 Simulators

If I can't get it out, I have the option of registering it at a relative's house where they don't have emissions at all. Thanks for the suggestion!

One suggestion too is to spend your time removing that section of exhuast and once off take it to a machine shop. They will be able to extract that for you and likely only 20 bucks or so. (VS hours of time) I presume you don't have a MIG welder etc on hand.

Then treat the exhuast system to all new rubbers and hardware upon re-assembly. Yes your sensor is likely original no one ever changes them even though their useful life span is really only about 10 years or 80k miles in my opinion.

I usually buy new 02 sensors and pull the exhaust like this in any new old MB I buy. This way I know the reliability and fuel efficiency should be good and also it makes future servicing a doodle having nice new hardware on the full exhaust. I use stainless bolts and serrated stainless flange nuts. They never degrade.

 

[emerydc8]

No MIG welder here. It is tempting to remove the exhaust and install new rubber, although if the O2 sensor is any indication of the exhaust manifold bolts, I'd probably find myself with several seized bolts.

 

[emerydc8]

Just to follow-up on this, the bolt extractor came today. I tried it first with my worthless Harbor Freight 1/2" "impact" driver that did nothing (I'll be throwing that out). Then I switched to a three foot x 1/2" drive breaker bar. I had to put most of my weight behind it but it broke loose on the first try!

So, to answer my original question, this $46 bolt extraction tool is definitely something that would be good to have in your shop. I had several of the smaller diameter tool kits but nothing that would fit around a stripped O2 sensor. Cheers!

MAXIMUM 1/2 Inch Drive Impact Rated Bolt, Nut & Lug Nut Remover Extractor Set, 5 Pieces. SAE/Metric Sizes: 3/4 inch (19mm), 13/16 inch (20-21mm), 7/8 inch (22-24mm), 15/16 inch (24mm), & 1 inch (25mm) - - Amazon.com

MAXIMUM 1/2 Inch Drive Impact Rated Bolt, Nut & Lug Nut Remover Extractor Set, 5 Pieces. SAE/Metric Sizes: 3/4 inch (19mm), 13/16 inch (20-21mm), 7/8 inch (22-24mm), 15/16 inch (24mm), & 1 inch (25mm) - - Amazon.com

www.amazon.com

 

[Kyiv]

Jesus Christ! Glad it worked out, but what a drama!

 

[emerydc8]

Jesus Christ! Glad it worked out, but what a drama!

Next I have to do the driver's side bank. I'm just assessing what I have to remove to get to it. Definitely the coolant reservoir and a bunch of wires.

 

[Jlaa]

I have seen lots of seized items like this! Usually I bite the bullet and remove the exhuast for 02 sensor removal on really old sensors due to bitter past experiences.

What I normally do is: Cut off top of sensor. Get a tight fitting impact socket and impact ready. Use MAP to heat the bung as much as possible, hit with some oil and 6 point impact socket. Usually that gets them. Then you will need a thread chaser tool for 02 sensors to clean up old threads.

If this does not work for any reason then I weld on a large nut so it is glowing red hot and gets proper purchase. Thread extractors will not work on something like this for me anyway especially in situ.....

@JC220, thanks for sharing your method. I recently got the dreaded check engine light on my sport beetle and I am steeling myself to fight the 2 L/R pre-catalyst O2 sensors (argh ob2).

I have a question about your procedure….. do you only apply penetrating oil AFTER apply heat onto the bung with a torch? No soaking the threads with oil for days beforehand? Also, how long do you wait after applying heat to apply the oil, and then how long do you wait for the oil do do its work on molten steel before hitting it with the impact wrench?

Also - why do you use a regular 6 pt impact socket? Is it because the special 02 sensor sockets flex too much due to the cutout for the wire? Thanks.

 

[gsxr]

Jlaa, have you tried soaking in penetrant for days yet, followed by wrenching? This is the first step before going all-in on cutting off the sensor.

 

[Jlaa]

Jlaa, have you tried soaking in penetrant for days yet, followed by wrenching? This is the first step before going all-in on cutting off the sensor.

I haven't done anything yet - I am just researching all the scenarios first.

 

[luckymike]

I haven't done anything yet - I am just researching all the scenarios first.

I’m guessing by doing all the due diligence beforehand, it’ll surprise you by popping right out.

 

[JC220]

@JC220, thanks for sharing your method. I recently got the dreaded check engine light on my sport beetle and I am steeling myself to fight the 2 L/R pre-catalyst O2 sensors (argh ob2).

I have a question about your procedure….. do you only apply penetrating oil AFTER apply heat onto the bung with a torch? No soaking the threads with oil for days beforehand? Also, how long do you wait after applying heat to apply the oil, and then how long do you wait for the oil do do its work on molten steel before hitting it with the impact wrench?

Also - why do you use a regular 6 pt impact socket? Is it because the special 02 sensor sockets flex too much due to the cutout for the wire? Thanks.

Note that most of those split 02 sensor sockets will not fit the fat 90s MB sensors! Don't ask how I know.

I just replaced an 02 sensor on my w140 a few days ago. I cheated and took the exhaust off the car however!

But, yes I cut the sensor due to aforementioned socket problems. You could heat it, oil it and try a spanner on it on car also it probably will come out.

In my case I cut the top off so a regular impact socket fitted then heated the bejesus out of it (technical term) and then sprayed it with some penetrant which fizzled around it for 10 seconds or so before hitting it with the M18 nut focker. Came right out.

The threads are normally in bad condition and mine did not disappoint. So I used that extremely important 02 thread sensor thread chase tool and cleaned them up.

My new 02 sensor had the anti seize smoo pre applied so no guess work. Do NOT put loads on as this could Foul and kill the new sensor.

It's easy enough don't sweat too much about it just make sure you have a good MAP torch and the thread chase tool and it will be fine.

 

[sheward]

As a general rule, apply oils and let them sit. The longer the better. Multiple times. I also apply oils after heat and while cooling however much of the oil just burns up with heat. My theory has been the heating and cooling cycles create gaps due to the objects cooling at different rates from size and material differences. This creates pathways for oil.

Folks in the know here recommend half and half mixes of Acetone and transmission oil as an alternative to penetrating oil

 

[LWB250]

I soak liberally with Kroil for at least a week prior to removal. Works for me, but in some instances has required the "split" socket so I can hit it with a hammer to set up some vibration to break it loose.

Dan

 

[JC220]

As a general rule, apply oils and let them sit. The longer the better. Multiple times. I also apply oils after heat and while cooling however much of the oil just burns up with heat. My theory has been the heating and cooling cycles create gaps due to the objects cooling at different rates from size and material differences. This creates pathways for oil.

Folks in the know here recommend half and half mixes of Acetone and transmission oil as an alternative to penetrating oil

I have about 19 penetrating oils and I can say that on my climate at least with lots of oxidation they do little to nothing. Spray them for a couple weeks but still no difference bolts will snap off and round etc.

The only way I do have success is as you say by applying copious heat so as to open up pathways then douse it and it does then make its way in.

On a separate subject candle wax is suggested as a very effective penetrant media using heat so I will try that soon also.

Ultimately heat is the boss of removing stuck fasteners period.

 

[sheward]

Yes, when dealing with the type of rust you are dealing with, it frequently ends with extreme methods. Heat is then the only savior, and it usually makes the difference.

 

[ace10]

What's the access look like?

Feels like I've always had to rely on this cheapie flexible 22mm wrench. And heat.

Can't recall ever having enough space for a special socket.

 

[sheward]

Veering off subject for a moment, here are some pictures of my attempt to remove some old and rusty bearing races from a machine I own. I do not have oxyacetylene torches, so I made do and was successful. I was unsuccessful in removing a bushing from the accompanying shaft. That took a HUGE scary press.

 

[Jlaa]

I soak liberally with Kroil for at least a week prior to removal. Works for me, but in some instances has required the "split" socket so I can hit it with a hammer to set up some vibration to break it loose.

Dan

Thanks. How come you hit the split socket
With a hammer? How come you don’t use the impact wrench a little bit at a time to ugga-dugga the vibes in there to break it loose?

 

[LWB250]

Thanks. How come you hit the split socket
With a hammer? How come you don’t use the impact wrench a little bit at a time to ugga-dugga the vibes in there to break it loose?

Usually because the sensor is at an angle that I can't get the heavy artillery on it. Otherwise, that's what I would use. That's one good thing about the split sockets - the heavy duty ones have a "boss" for hitting it with a hammer.

Dan

 

[Jlaa]

I’m guessing by doing all the due diligence beforehand, it’ll surprise you by popping right out.

Winner winner chicken dinner @luckymike!! . Even for someone as inept as me, it took me more time to jack up the car than it did to loosen two 02 sensors with a regular 22mm wrench. Score! @RicardoD it looks like we paid the German Car Karma far in advance with that brutal starter motor replacement ……

Now to cancel all those 02 sockets I ordered on Amazon, put away the PB blaster and torch which I do not need, and wait for Rock Auto to deliver the o2 sensors…..

Man this was ridiculously easy. There must be a catch. Thanks everyone for your kind wisdom!!!

Yet… foiled AGAIN … because there was no need to use my newly acquired Milwaukee impact wrench!!!

 

[luckymike]

YES!

 

[ace10]

Damn. No blood. No cursing. No specialized tools.
What is this world coming to???

 

[Jlaa]

Damn. No blood. No cursing. No specialized tools.
What is this world coming to???

Well….. I DO have a 22mm crows foot wrench on order because without that, I do not know how to torque an 02 sensor to 35 lb-ft……

 

[gsxr]

Well….. I DO have a 22mm crows foot wrench on order because without that, I do not know how to torque an 02 sensor to 35 lb-ft……

You use the proper German method of "Gudentite".

 

[JC220]

Well….. I DO have a 22mm crows foot wrench on order because without that, I do not know how to torque an 02 sensor to 35 lb-ft……

I come across this sometimes and whilst using a spanner I say "click" out loud when it feels right. The click means it is torqued to specification