1993 80 Series - Just Joined need some help :)

[TetonShady80]

Howdy! Just joined I have a 1993 FZJ80, got CEL code 28, for O2 sensor no. 2.

I have the new O2 sensor, however the currently installed sensors direct thread bolts are rusted to nothing. I cannot find anywhere online or in forums the size and treatment I need to replace these.

Additionally the Cats bolts are rusted to nubs and since I’m baselining this new rig I’m kind of in the “while I’m here” phase/mindset. I cannot find the bolt size/pattern/treatment for those flanges that connect both the up and down sides of the cat to the “Y” exhaust tubes.

Happy to be here and thank you for any help or guidance!

 

[Brindleboxer]

Welcome to the world of 80's ownership.
Suggest you go to the resources section and download the FSM and EWD for your year as they are free and invaluable resources to have. In addition, you will find the search engine within Mud is lacking to say the least. Most usually just go to their search engine of choice and put in IH8MUD 80 series and whatever they are looking for.

 

[TetonShady80]

Welcome to the world of 80's ownership.
Suggest you go to the resources section and download the FSM and EWD for your year as they are free and invaluable resources to have. In addition, you will find the search engine within Mud is lacking to say the least. Most usually just go to their search engine of choice and put in IH8MUD 80 series and whatever they are looking for.

Thank you! Didn’t even know there was a resources section this is the first forum I’ve ever joined in all my life!

 

[Brindleboxer]

Here is the link to the resource section, if you haven't found it yet.

Resources

forum.ih8mud.com

Also, I usually say to add your vehicle info in your signature line, that way you don't need to think about putting it in every post.

 

[67cruiser]

I say... pay a guy to do that hard work

 

[discoverydave]

The O2 sensor on the FZJ80 — that's a 22mm hex, same thread pitch as a spark plug (18x1.5mm). The bung in the exhaust pipe is the one that'll give you grief if the threads are rusted, not the sensor itself.

For seized exhaust O2 sensors on these trucks I've had good luck with a propane torch warming the bung for a few minutes before trying. The penetrating oil approach takes patience — days, not hours. Kroil is the go-to if you can get it, PB Blaster as second choice, apply and let sit overnight minimum.

The cat flange bolts on the FZJ80 Y-pipe junction — those are typically M10x1.25 nuts/studs. If the studs are rusted to nubs you're probably looking at drilling them out and rethreading, or using a stud extractor kit. Heat is your friend there too.

While you're in there it's worth checking the flex pipe section — that's a common failure point on the 1FZ-FE exhaust and new ones are cheap before they turn into an issue. Welcome to the 80 series club, these trucks are worth the labor.

 

[60 toy ota]

Penetrating oil and THEN light air hammering (or similar) to help break the rust bonds and help the oil work its way in. Heat is great if you have it. Find whatever 6 point socket (metric or sae) that just barely doesn't fit to where it can be forced on with a hammer. Use a hand wrench, not an impact. Once you get it to budge stop and tighten it back up, and alternate between tightening and loosening, gradually getting looser each time.
In desperation you could also use a nut splitter. If you're not in a rush apply penetrating oil periodically over the course of a few days.

You'll get it. I used this method on a 94 and all 4 came out leaving healthy studs, and some of the nuts walls were literally paper thin.

Edit: @discoverydave typed faster than me Haha