O2 Sensor Replacement Problem (1 Viewer)

[sjpitts]

I just ran into a serious problem replacing my O2 sensors. 93 FJZ80.

The first one (passenger side) was replaced easly.

The second one (driver side) is giving me serious grief. I got one nut off the second sensor without a problem. The second nut on that sensor was coming off, but started getting harder and harder to turn till it stopped.

I got looking and it and it looks like it is cross threaded. I don't know how something could get cross threaded coming off, but it looks like it is.

I tried to screw it back in, but that is tough to. There is not much room to move in there.

In retrospect, I shouldn't have been forcing it off--but who ever heard of a nut becoming crossthreaded when it is coming off?

I have no idea what to do. Try and split the nut? Cut the stud? Can that stud be replaced?

There is not much room up there, but I really don't want to try and take the exhaust pipe off.

I hope the picture works.

Jared

 

[whodat]

likely it was put on wrong before you got it, unless you're the orig owner.

 

[Rich]

Presuming you don't want to have to weld a new stud to the pipe, I would suggest that you attempt to cut the nut. Not clear to me if you can fit a nut splitter in there. You may consider using a small abrasive cut off wheel mounted in a drill or dremel tool to split the nut. Don't cut the stud. You could also consider, again using a small abrasive cut off wheel, cutting off the left flange of the sensor so you can then remove the rest of the sensor and get it out of the way. If you attempt this be careful to not cut all the way through the gasket into the pipe.

After you get the nut off you can then rethread the stud using the proper size metric threading die. The picture focus is poor, but the exposed threads don't look too bad.

 

[Lars]

I've only been a Cruiser owner for a year and have no idea where your picture is but perhaps you can get a dremel tool in there........ or one with the long flexable attachment.

 

[Scamper]

I have a '97, and so this may not apply to your model. But the studs on the '97 come out and can be replaced--I know this becuase one did come out on mine and the other did not.

If for some reason you can't remove the nut and the stud is unable to be removed, I'd go with the dremel with a cut-off wheel, being careful not to cut too much into the threads (though some will be inevitable). The angles are tight, so you might have to cut it off at a 45-degree angle.

But if all else fails, just keep wrenching it off (perhaps by applying copius amounts of PB Blaster); worst case is that you bust off the stud and you have to weld another on.

When you put the new nut/stud on, be sure to use some anti-sieze.

 

[cruiserdan]

You can replace the studs, no problem. Spin the nut off and chase the stud with a 8x1.0 die. If the stud comes off with the nut, replace the stud.

 

[sjpitts]

After hearing that the studs could be replaced, I just went ahead and tried to get the nut off. I pulled on it with all my might and the stud broke.

Fortunately, it broke right at the top. It looked like ths stud backed off a little, but I don't know if it would easily come out-- after all, it broke rather than unscrew the rest of the way.

I didn't have the proper sized die, but I tried to screw on the new nut and it went right on just using my fingers. So I went ahead and put in the new 02 sensor. I was able to tighten the nuts as tight as I could and it seemed to hold ok.

I took some more pictures as best I could laying under the truck. One sort of shows the top of the stud where it broke (but is real fuzzy). The other shows the bottom of the stud, showing how it backed out a bit.

Like I said, I was able to tighten the nuts as much as I could given the tight quarters. Do you think it will be ok, or do I need to replace that stud? Right now, the top of the broken stud is just under the top of the nut.

Jared

 

[cruiserdan]

You should be OK.

 

[Beowulf]

Leave it. It's not like your wheel is gonna fall off.

-B-

 

[Klunky Chris]

for interests sake, there is a factory recall on the 93 O2 sensors.
If your 93 hasn't had the recall done yet, Toyota will give you a pair of new ones for free.. with labor.

I got mine done about a year ago with 165K on the clock.