proportioning valve leak

Anybody ever tackle a stem leak in a Speedway adjustable proportioning valve? Can they be repacked or re-sealed somehow?

 

I thought it would be like a hose bib in that they would have a nut to tighten down on the packing gland.

If you're running the purple one as shown in the online catalog you may want to open it up and see if an O-ring would take care of the problem.


http://www.speedwaymotors.com/xq/aspx/path.242/img.910-31355(06)_L/deptId.9/displayId.1977/qx/ProductLargeView.htm

 

Thanks C9. This valve actually belongs to a friend of mine. He said he did open it up and inspected the O-ring - which looked fine. So maybe just tighten down on the nut on top? And maybe swap out the O-ring to be on safe side?