Where to find packing to fix shut off valve?

All the ones I have ever seen on the old CAT equipment have been a precision taper with brass on brass (at least that's what it looks like to me)

I see similar stopcock valves on propane supplies to furnaces etc. I would think best to just replace it if it won't shutoff tightly or leaks around the part that turns.

ccjersey, thanks for the reply. Well, yes the valve is brass on brass, with the taper. But, I am talking about the top where the cap screws on that holds in the taper shaft. There is packing under this screw on cap and seals around the small shaft that has the square sticking out the top. There is some type of packing in the top part (under the cap) keeps fuel from seeping out. I have tightened mine before and stopped leaks, but this valve has worn out packing.

I went to a local hardware store during lunch and picked up two types of packing in the plumbing department. One teflon and one of graphite. I don't know if the teflon will be bothered by the diesel. I think I will try that first since the packing cord was larger diameter than the graphite cord.

I know that Teflon packing is quite good in packing glands for bronze propeller shafts for sailboats, and such...We also use teflon tape on all pipe fittings when installed...I would think that the Teflon packing would be the best...since it is not affected by fuels and other chemicals...
Respy, CarlsCAT

thier really shouldnt be any packing in that valve it should seal on that taper if you look close the taper and shaft should be one piece you can get a new one at the plumbing store the nut on top is suppose to apply pressure for sealing

There is a preformed packing in that valve between the hex cap and the plug. It is probably either cotton or asbestos impregnated with grease and graphite. finding one is going to be tough.

There is a preformed packing in that valve between the hex cap and the plug. It is probably either cotton or asbestos impregnated with grease and graphite. finding one is going to be tough.

I've got a couple of the hex-cap fuel tank valves for my D2 on my workbench... I'll have to open one up and take a good look at it...As I recall, packing for the packing gland on boat stuffing boxes for propeller shafts, is braided and impregnated with Teflon or graphite...The packing can be flattened out, or un-braided...I have used pieces of packing on small valves like the ones on sediment bowls...when an O-ring was not available, or work...It's been a long time since I worked in a chemical plant, but globe valves, particularly those used in steam lines, use packing under the bonnet, or hex cap...A marine supply store would be a good source for the packing...
Respy, CarlsCAT

I've got a couple of the hex-cap fuel tank valves for my D2 on my workbench... I'll have to open one up and take a good look at it...As I recall, packing for the packing gland on boat stuffing boxes for propeller shafts, is braided and impregnated with Teflon or graphite...The packing can be flattened out, or un-braided...I have used pieces of packing on small valves like the ones on sediment bowls...when an O-ring was not available, or work...It's been a long time since I worked in a chemical plant, but globe valves, particularly those used in steam lines, use packing under the bonnet, or hex cap...A marine supply store would be a good source for the packing...
Respy, CarlsCAT

OH, I see.........you have a gate valve instead of a stop cock. Most of the ones I have been around have a 1/4 turn stop cock you use a wrench to turn. Your packing should work just fine as a stem seal. Many times just some string wound around will also work along with the remains of the old stem packing.