round column mill drill

[wazrus]

G'day! I have a geared-head round column mill drill, model number is ZX28. It dates from around 1996. It's been quite OK, contrary to much commentary on other sites. In the value-for-money stakes, it's hard to beat.
However, It has developed an oil leak from the quill housing, I suspect the oil seal betwwen the housing and the cast head body. The quill and its bearings etc seem to be quite OK, but this particular oil leak has become annoying. My problem is just how to remove the housing and quill from the machine. I've completely dismantled the gearbox: no problems, but 'getting at' the offending seal is an issue. I can see that the torsion return spring will have to come off and past experience with pre-loading such springs hasn't been all that good! I have removed the worm-drive downfeed mechanism.
The quill and quill housing (that's the part with the machined downfeed teeth) are now quite accessible, but the trick for me is in getting the housing out of the cast body, then the quill out of the housing!
Hopefully, I've explained the problem clearly???
Any ideas or anybody with experience??
Thanks
Wazrus
Ps I have a 'manual' of sorts, printed in chinglish: it's not all that helpful...

 

[Septic]

In my experience, the importers of Chinese machine tools often have to repair or "fettle" a fair proportion either before they are dispatched to the buyer, or when they are returned if they don't work... Hence the appalling reputation they often have, which if you consider the price is grossly unfair.

So phone the people you bought it from and ask to speak to their resident fitter as he's probably done a good few..