Exhaust Stud Nuts

[Batsoff]

Hello All...

I'm getting ready to replace my exhaust on my 2000 4Runner Highlander (both cats, muffler, etc... ).

I wanted to make sure I could get the 3 nuts that hold the 1st CAT to the manifold down pipe loose as they've been on the truck for years at this point.

I was able to back out the 1st nut, but could not run it back up the stud bolt once removed... almost like it cross threaded itself?

I know these nuts are not supposed to be re-used... but is there anything about this nut that prevents it from being used twice?

These are the nuts in question - 90080-17187.

See attached pic... circled in red.

Thanks for the assistance.

** EDIT ** I went out one more time to try to get the nut off with my impact wrench and it was definitely cross threaded onto the stud. The entire stud backed out with nut still attached. Glad to have it off, but would still appreciate any info that can be passed along. Want to make sure I have all the necessary parts / pieces for my exhaust install.

-batsoff
2000 4Runner Highlander

 

[024rnrSport]

That's about the worse place there is for cross threading. I had one nut that was problematic and almost ruined the thread in the flange. I personally would replace the stud and nut if possible and coat liberally with anti-seize.

 

[A2toHgt]

What your're experiencing is very common.

They're probably copper nuts. They are meant to be single use only. If the stud isn't threading nice, chase the threads with a die. I did this on my race car and the nuts tightened up nice.

 

[Batsoff]

Thanks 024rnrSport & A2toHgt...

I was able to replace the stud and nut without much issue. I also picked up a few extra studs just in case I run in to similar issues when replacing exhaust.

 

[gamefreakgc]

Thanks 024rnrSport & A2toHgt...

I was able to replace the stud and nut without much issue. I also picked up a few extra studs just in case I run in to similar issues when replacing exhaust.

When trying to get those apart, I tend to have 1 out of 3 studs back out instead of the nut. No way to get the nut off at that point either. Having extras is a good idea.