E30 Zone

I intended to replace clutch fluid and bleed system on my 325 Touring.
I emptied out the clutch reservoir to find the bottom of it filled with with black oily sludge.
I wiped this out, filled with clean fluid and tried to bleed system with a gunsons eezibleed.
Could not get fluid to pump out bleed nipple at all using gunsons or pumping pedal. I cleaned the nipple with an airline and it was fine
I gave up and clutch is still ok.
I suspect the fluid in the system is untouched apart from the reservoir.
Any ideas why system wont bleed through?
Should I just leave it alone whilst it is operating ok or am I inviting trouble with the slave cylinder?

If you open the bleed nipple, press the pedal, and the clutch still operates, then the bleed port of the slave cylinder is blocked. Not that uncommon.
Sounds like clutch fluid replacement might have gone undone on this car for quite some time (if ever!- also not that uncommon), and the sludge might be all that's providing a seal.
New fluid and it might leak like a sieve!

Thanks Brian
Yes I actually unscrewed the nipple and it had no fluid on it at all.
Not sure whether to replace slave cylinder or just leave it for a bit as it is okay although slightly heavy.
If I remove old slave will all the crap come out or will any sludge in the line then go into new slave and cause probs in future?

Sludge from an old master cylinder can, and does, often wreck new slave cylinders. That's why it's always recommended on here to change both at the same time.

Ok . Thanks Brian, sounds straightforward .

had the same prob m8 changed master and slave now all is good