Removing a BX16v alternator

[szhrr5cc]

Hello All, working on our 16v to remove the alternator as it very noisy and either needs replacing or rebuilding. We have freed it off apart from one electrical connector which we are having great difficulty in removing as there looks to be a ring connector held between two nuts which looks as though we need two spanners to remove i.e. with one held in place and the other turned. However, the bottom of these is obscured by some sort of red coloured ring which prevents a spanner being inserted.

This is pictured and is at the top of the arrow in the picture.

Anyone know what this dark coloured ring is for? We are thinking of simply cutting the wire so we can get the alternator out and then deal with this thing once it is off the car.

Any other ideas ?

Thanks

[Kaapelimies]

Don't break it, get a slimmer open end spanner, with help of an angle grinder for example. That black plastic ring is an insulator, as the bolt is "hot", directly in battery plus without a fuse.

[szhrr5cc]

thanks, will give that a try, well worth knowing!