How do I remove the post-cat O2 sensors?

AaronPaul

AaronPaul

TJ Enthusiast
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OK so I am replacing both o2 sensors post cat in my 2000 4.0 TJ. How in the heck do I get to these. Especially the one closest to the oil pan and transmission (manual) There is little to no room. I plan on getting the special socket but I'm not even sure I can get the darn socket in that tight space. Anyone come across this or have a trick?
Thank you guys
 
You can usually rent the kit from your local auto parts store that has the stubby socket. All else fails, and since you're replacing it anyways, you can just cut the wires right at the sensor and put a box wrench on it. The new one can be installed with an open-end wrench. It's not like the torque spec is ridiculous. I've had to do that a few times over the years. Never failed me when I didn't have the right tool.
 
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kickice24 said:
You can usually rent the kit from your local auto parts store that has the stubby socket. All else fails, and since you're replacing it anyways, you can just cut the wires right at the sensor and put a box wrench on it. The new one can be installed with an open-end wrench. It's not like the torque spec is ridiculous. I've had to do that a few times over the years. Never failed me when I didn't have the right tool.
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Thank you I will certainly look into that. I am hoping its just bad o2 sensors
 
I Have use a pipe wrench before and that was easier than the socket. If you can get a crows foot vs the regular one you can sometimes get a good angle. I dont see the crows foot being used enough!
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Use any of the sockets recommended above except for the second one with the slot milled up its side. That type is for installing a new O2 sensor, the slot cut into it weakens it too much for it to be reliable for removing an O2 sensor which is commonly seized.

This is the type that is ok for installations, it's not strong enough for the usually much tougher removals.

Capture.JPG
 
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Jerry Bransford said:
Use any of the sockets recommended above except for the second one with the slot milled up its side. That type is for installing a new O2 sensor, the slot cut into it weakens it too much for it to be reliable for removing an O2 sensor which is commonly seized.

This is the type that is ok for installations, it's not strong enough for the usually much tougher removals.

View attachment 262653
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Yea they suck. I also have had issues with the wiring being twisted on the side cuts.
 
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if ur gonna use the hand tool make sure you got some cheater pipe. My oem 1 was in there so tight i had to put in the vice heat it and work that bad boy pretty good.
 
AaronPaul said:
OK so I am replacing both o2 sensors post cat in my 2000 4.0 TJ. How in the heck do I get to these. Especially the one closest to the oil pan and transmission (manual) There is little to no room. I plan on getting the special socket but I'm not even sure I can get the darn socket in that tight space. Anyone come across this or have a trick?
Thank you guys
Click to expand...
I just did this job and can hopefully help. I used the Tekton socket as shown in another post this thread (3rd pic in from left). Several days before attempting to loosed I soaked the base of the sensor with Kroil. I have found Kroil to be superior to all others as it creeps into the threads via capillary action. I managed to loosen three of the four sensors and squirted a little more Kroil on the threads as I snugged them back tight as I was still waiting on two sensors to come in. Bank 1-Sensor 2 downstream front manifold was tight and several attempts to break loose were unsuccessful. I could have muscled through but really didn't want to screw anything up so I applied more Kroil, tried loosening and repeated over several days. Finally, after about the third or fourth day I broke it free. Squirted more Kroil on the threads and loosened and tightened in order to distribute the Kroil all around the threads. Mind you, I used a 3/8" ratchet with no cheater bar and used a lot of patience. Oh yeah, I yelled every profanity I know and came up with some new ones in the process. Here is a pic. of the bastard.

DSCN1808.JPG
 
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