Replacing O2 Sensors

[sjpitts]

I have a new pair of O2 sensors waiting to be insalled in my 93 80. I looked in the FSM, but I did not see much info.

I took a look at sensors and it looks like you would need to remove the exhaust shields, but I wasn't sure about that.

So does anybody have any tips on replacement?

Jared

 

[Scamper]

Did the same on my '97, but don't know how similar/different a '93 is.

I didn't need to remove any heat sheilds, but I found the nuts on the studs to be badly..."distrubed". Don't know if it was some corrosion, but they were well rounded by the time I got to them. I would recommend you get some Craftsman bolt-offs. They're the ticket.

 

[lc1996]

Jared,
I replaced one of mine on my 96. Soaked the nuts/studs a few days before taking the the nuts off. One of the nuts was rounded as you described, but was able to use a vise grip to get it off, then picked up a couple of new ones at the stealers to replace.

Carl

 

[archie]

If you can't get it off with a vise grip try a pipe wrench. More leverage.

 

[cruiserdan]

The original Toyota SSC (Special Service Campaign) had the mechanic remove the front exhaust pipes as part of the O2 sensor replacement procedure.


Practical experience dictates that exhaust pipe removall is not necessarily required.

I have succesfully replaced both sensors on my 93 WITHOUT removing the exhaust pipes from the chassis. This process requires patience and proper tools AND an exhaust that has not been subjected to "salted roads" winters.

I suggest that you get under the vehicle and reconiter the mounting area to determine the degree of corrosion.

D-

 

[landtoy80]

My nuts were well rusted.
I had to remove the exhaust pipes to get the nuts off.
You will need the gaskets fro the cat and manifold if you are lucky enough to have to remove them.
The cats nuts are a bear to remove too. I had to grind and cut them off.
I used SS bolts and nuts as replacements on the cat. They were not high grade SS bolts but they have lasted over a year. The make removing the cat SOOOOO much MOREBETTER.
Someday I will get some high grade SS bolts for it.

I broke off the studs on the shield (rusted). I drilled new holes and used SS bolts/nuts there too.

 

[sjpitts]

My 80 has spent its whole life in the Phoenix Arizona, and we don't do salt on the roads for obvious reasons. So with any luck, I will be able to do the replacement without removing the pipe.

CruiserDan-- what would be the "proper tools" needed to get the O2 sensors out without removing the pipes?

Jared

 

[Arya Ebrahimi]

Jared, I replaced the 02 sensors on my '94 w/o removing the pipes or the heat shields. I believe the nuts are 10mm, so you will need a 1/4" drive ratchet(because a 3/8" drive ratchet is too big to fit into the tight space) w/ a 10mm socket and a 10mm box wrench. I'm pretty sure that's all I used to swap them out. It was definately an excercise in contortionism(is that a word? lol) but it's doable. It helps if you have smaller/thinner hands. You might need a small flathead screwdriver to help depress the release tab on the wiring connectors.

The only advice I can give on the actual process is to be patient and although it is absolutely nerve-wrecking at times, one or two of the nuts require you to loosen and tighten them 1/8 of a turn at a time. Squirting PB Blaster on the nuts ahead of time will help as once the nuts are no longer tight you can turn them off by hand.

Ary

 

[landtoy80]

The other problem I had was the gasket.
The gasket was rusted too the pipe. I had to chip,poke and grind off the old gasket.
No way you could get all the old gasket off without removing the pipe if its rusted/melted/bonded on.