could you ask him if what he did was similar to thisWhen my b/f did it, no way did he drop the cat. He used some heat to free up the sensor, but other than that it was easy.
Thanks. Inspired by your steps, I managed to change my pre-cat O2 sensor without dropping the catalytic converter AND without remove the rain cover & black metal shield. Here's my steps:I recently replaced my front O2 sensor, but I accessed it from the top:
1. as above
2. Remove windscreen wipers and black plastic rain cover
3. remove the black metal shield
4. remove engine cover
5. Access O2 sensor. I bought a special socket, see attached file. It allows you to use a normal sochet wrench without damaging the cable.
6. Do steps 4 to 1 in reverse order.
it's not too hard, but kinda difficult to access. If accessing from the top please don't forget to either cover the paint or wear clothes without metal parts. You don't want to grind the paint with your belt.