The photo appears to be upside down but one can get the gist of the story!

The ACE fluid has been leaking really badly. I’ve just had a good look and cleaned some of the fluid off around the area. It would appear that it is not the pipes that are leaking, although some are quite corroded; but the large nut on the block itself.

Does anyone know if this is some kind of filter and requires an O-ring?

A quick search around the interweb and a service kit which includes new filter and O-ring can be purchased.
I’ve lost so much fluid that I just need to purchase more ACE fluid now.

Iv never yet found an Internet or ebay filter to fit they all seem to be for earlier discovery models.

The O rings however have fitted. Often the screw in plug is damaged by some previous monkey fisted person. As the filter is metal a quick blast of carbon cleaner will sort yhat. Some on here have used ptfe tape on the treads as well.
Good luck

The vendors of filters all say “suitable for Discovery 2 and all RRS models 05-13”, but like you say, at least I can use the large O-ring and give the existing filter a clean if necessary.

I’ve ordered items that are now in the post. I’ll let you know next week if I was successful.

You'll probably find that the aluminium has reached with the steel, and corroded away

Look closely, you'll see the o-ring poking out underneath the plug...

The parts might turn up on Monday so I’ll be able to take the plug out for inspection.

https://www.rrsport.co.uk/forum/topic62392.html

Thanks for the info. All the ones for sale seem to have the larger band on each end. Like you mentioned, I might just be using the O-ring and flushing the old filter out…

From your previous link, one chap’s method of sorting out the ACE problem out was to purchase another vehicle…yikes!