newshound wrote:
I suspect that 'this is not a good thing'.

Any ideas?

--
Dave - The Medway Handymanwww.medwayhandyman.co.uk

My SDS (chepao from screwfix) has always done it, it comes from the
hammer action at the back, when it warms up it runs out the front!!
they must have known as there is a little hatch, and a pot of grease
to top it up! been working fine (and hard) for 5 years !!

Ditto. The black colour comes from fretting wear, probably from the
hammering faces: very finely divided iron and/or iron oxide. You need
very little wear to make the grease black: don't worry about it.

It was being used in chisel mode at the time, it did get rather warm so I
guess thats what it was.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk