I have a 307 S12 and it's loosing oil from the knee. It is leaking from under the machine. Is there a seal on the elevation screw that operates the knee?
I am thinking that it is draining down into the vertical cylinder that covers the screw.

A little more info would be helpful.Is the oil actually running out from under the machine and on to the floor?If so I would speculate that the expansion plug in the elevating nut extention is either rusted through or it's some how popped out.It's going to be a major operation to find out.

If it's leaking onto area where the coolant drains then it could be something as simple as a gasket but still a major PITA to repair.Whatever is going on please keep us informed.If I'm wrong about this there are plenty of others here that are more knowledgable.

I have a 2h and mine was pumping the oil out of the knee by leaking from the pump where the splined shafts turn next to the flywheel. Mine was missing 2 screws that plugged the holes abd the oil was pumping out he two holes and draining into the sump. I could see it leaking out when the mill was running so I plugged the holes and it works fine it still leaks a little so I keep it toped off.

Oil is coming from under the machine. It usually takes about a week to empty the knee as it is now.

The first thing I'd do is run the knee up as high as I could get it.I'd run the table all the way out to the front of the knee so you can access the elevating bevel gear cover.I'm trying to take into account that your machine is much newer than either of mine.Next support the knee so that it won't fall when you remove the elevating screw.You'll have to leave yourself enough room to work the screw out.

Once having done the above remove the elevating bevel gear cover.Then remove the large slotted screw.Now go to the underside of the knee and remove the screws that secure the elevating screw shield and pry it loose.This can be a leak scource so make sure it's sealed good when reassembly takes place.loosen the elevating nut extension and trun the elevating handle to make the screw retract up toward the bottom of the knee.Take the whole thing out and you'll see the expansion plug on the bottom of the elevating nut extension.

On mine , the y axis screw covers that plate. Should I remove the screw?

I'm not sure if you should remove the screw or not.If you have a manual with the breakdown of the machine I'd like to see the section on covering the knee.As I said I'm working with older machines/manuals inorder to try and help.I personally wouldn't attempt taking it apart without a manual.

The manual scan is too large to post here. I can email it to you.

machfab,

Sent you a PM.

There is a drain plug on the bottom of the knee, its aluminum, it has an o-ring. Make sure the o-ring is there and that the plug isn't cross threaded. Also make sure the knee is not over filled.

Is it under the machine?