92 740 turbo...how to replace O2 sensor?

Have a new NTK sensor. The sensor is just behind the turbo, and it
projects downward through a metal shroud. There is only about enough
clearance, once shroud is removed, for a 4 in. open-end. IE, there is
not enough clearance for an open-end wrench....not with the exhaust in
place. Its questionable whether I could find a deep socket deep enough
to work....and only would be usable anyway to remove the old one, as
there would be wires still attached on the new one. It would be a big
job to disconnect the exhaust from the turbo and drop it, as there are
sub-frame parts that have to be removed. The lousy Haynes manual gives
no details about how to actually remove and install. Is there perhaps
some special tool I can get for this? Surely there is a way to
replace without dropping the exhaust?

 

Get a O2 sensor socket. They usually have them to Loan out or rent at
Auto Zone or most chain type Parts Stores.
You could also use a six sided tubeing wrench. Make sure you use the
correct size wrench or socket, or you will round off the corners of
the sensor, Then you will have to remove the Pipe..

 

I used an open ended spanner and it can off very easy as it has only a
couple of threads as I recall.Remember to used some moly lube on the new
part so one day it can be removed with out any issue.Remember to spray the
the part first and let it soak before undoing the O2 sensor.