I'm having difficulty replacing my 02 sensor. I've PB blasted the nuts and I'm trying to figure out what size the nuts they are. Anybody have an idea or have any tips? I have a 1991 4wd 22re. Thanks!

 

Can't remember, have you tried a 10MM 6 point socket? Could be a 12MM.

 

I soaked mine with PB Blaster for about a week, then used a steel brush on them, then ended up cutting into them with a Dremel/air grinder. Be careful not to hit the stud threads.

Once you take out an edge with the dremel, they should come right off. They are either 10 or 12 mm, six point.

 

Like TNRabbit says, forgot I brushed down the tops of nuts real well too. Mine came right off.

 

On my '99 they came right off after 2 doses of liquid wrench about 3 days apart, then a 12mm socket.

Good luck-

Scubaduck

 

might help if you run the motor long enough to warm the exhaust. a little heat helps a lot just don't burn yourself.

 

It's more effective to hit 'em with a blow torch...

 

they are 12mm but if they are anything like mine they are probably welded on by heat then rounded off.

 

When I took mine off, I was able to get my air ratchet on them and it worked( i think it does 60 lbs in reverse....)

Kat

 

WHatever you do, replace them with new ones. Don't forget to get a metal gasket, too.

 

i can get mine off. so then i planned on taking the whole downpipe off but i cant get that off either. the bolts are so ˟˟˟˟˟˟ rusted. drenched in PB blaster and the bolts just do not turn. the head of the bolts just bends and strips.

 

time for the sawzall!~!

Kat

 

i had to take the whole pipe off and change it... Former owner had welded a bung on and used a cheapo thread on 02 sensor tho

 

i have a full cat back so i cant be cutting things off. right now im looking for a good replacement to compliment my cat back. i want a downpipe with a high flow cat that i can bolt on.2 1/4 insh. the nearest reasonablely priced muffler shop around me is operated by a full on coke addict.

 

+2

cut em off

replace with new bolts

 

Wizard wheel and replace them with new studs and nuts. I have never had any luck with penetrating oils because as soon as you drive the oil is burned off .

 

If it is a 12mm socket, it'll be an M8-1.25mm nut. I have an LC Engr. header on my '85 and use a pair of stainless steel bolts, nuts, lock washers for mine and it works great. Been on for about 8 years now and comes off as easy now as the day I installed the header.