Yop
I'm sure this has been covered in more detail and with pix by others but as I have just done this I thout I'd share
my mini has an oblong box shaped brake fluid reservoir with 2 electrical contacts on the cap
if you are gentle with a screwdriver you can dismantle the whole cap - it has a float in it
and mine was full of gunk and one of the electrodes was heavily sulfated
cleaned up with a toothbrush and some brake cleaner and a good scrape with a file on the electrode
you don't really want all that gunk going down your brake lines - just thought that might be of interest to some the next time you do a fluid change











