Im having a problem getting my downstream O2 sensor to break loose. I have used buster to break away the corrosion and used many tools to grab and try and bust it loose but no way it wants to budge. I also don't have much leverage being as I only can lift the car so much using a jack. Any suggestions. Also I stripped the nut.

 

I assume you mean a can of PB Blaster. This is a rinse and repeat process. Soak it let it sit for a couple hours. Try it again, and if it doesn't work give it some taps with a hammer to try and break up the corrosion and then blast it again and let it sit.

I had an O2 sensor that was stuck like this. After a few days of repeating the process I was ready to torch it. Gave it a third (or was it fourth or fifth?) dose of the PB Blaster and finally broke it loose.

 

For future issues, it helps alot to have a o2 sensor socket. Alot less slip than a wrench. I need to pick up one myself

 

PB Blaster and two wrenches. Use the open end on the sensor and fanagle the second wrench into the closed end of the first to create more leverage. Like this

 

This may be a lot of work, but probably safer and more effective than working under the car. Unplug the sensor, remove the cat and work on a bench.

 

So you trade 1 rusted bolt (o2 sensor) for 5 rusted bolts on the cat?

 

I second that.......And those bolts that are on the CAT are a major pita to get off too! Air tools are your friend there.

Though this might be your only option at this point if the O2 sensor is now stripped.

 

I bet it will come lose if you get that car more than 1'' off the ground, use a fat ass wrench and do what was mentioned above, PB-wait-PBwait then attack that f@#ker like never before, but get a real jack so you can get some beast mode behind it, and also dont slowly apply pressure, apply force all at once, it will come

 

If it's stripped completely get a cheap 12" pipe wrench. Use a short length of pipe on it. Are you using jack stands? If you are not, buy those first.

 

If you tried it when it was completely cold, try it when it's hot. The difference in metal expansion might make it easier to remove.

Another option....ever seen those As Seen On TV sockets where it's got a number of sort of loose rotating little rods inside the socket? A friend was able to use that to get a rounded off bolt when nothing else would work.

Third option, just say "F it" and leave it on the cat. It doesn't affect drivability, and is really only important when it comes to smoging the car!