How is the piston on an old manual vac. pump repacked using leather sealant(packing) for which it was designed?

I have several antique manual piston vacuum pumps all of which need the pistons "repacked" with leather gaskets. The leather sealing gasket is specific for this type of antique pump and allows the lubricated piston and leather sealant to provide an airtight seal between the piston and the internal cylinder walls into which it inserts. The piston rod is pushed inward by way of handle which is attached to the piston rod in the cylinder. On manually pulling the handle or lever outward, and thus the piston, air is evacuated from a bell jar via tubing and a valve, the bell jar resting on a round metal plate or stage (sealed with vacuum grease) to which the tubung communicates and subsequently communicates with the pump. Upon pushing the pump lever inward (and thus the piston), air pulled into the pump cylinder on the evacuation stroke is vented to the exterior by means of a one way communication between the fore side of the piston and the aft side of the piston and to the atmosphere by way of a hole in the closed end of the piston cylinder. The cycle is repeated as necessary. Does anyone know how to repack the pistons with the required leather seals, or have a source for the leather seals, or know of a craftsman who knows how to accomplish repacking of these historical pumps (antique scientific instruments). Thank you for your attention to this matter.

as far as I know ( i freakin' HATE acronyms ) a leather seal in a cylinder is just a leather disc a little bit larger than th' cylinder bore and secured to th' piston by a metal disc a little bit smaller than th' bore !

th' leather disc edge is tuned up over th' edge of th' metal disc and makes a fit just barely less than tight enough to sieze up in th' bore !  when it has seated in it will be just right !!!
Re-design8 years ago
Start here.
THen google "leather piston seal" and "leather piston cup".
Air guns use the. Old 1920's - 1950's cars used them. Water pumps like those that were run by windmills used them.

If you can find an old water pump service man he can help you.

It's not a dead are but to get experienced help you might have to work some. If you have several I would just pick one and go to work on it after I've done my research and make it a real diy project. If it ain't working right now the it can't get much worse.

Good luck and make an instructable of it if you go it alone.