We have been selling specially-sized O-rings for plunger-filler ("vacuum-filler") packing unit repair for quite a few years, but not any more. Instead, we will be offering a significantly superior alternative, shown above. Instead of a simple donut-shaped seal, these incorporate two sealing flanges on both the exterior surface and in the central bore. Two sealing points instead of one is not only more secure, it also reduces friction while greatly improving lubricant retention within the seal. You can now order them here, or as part of our plunger-filler repair kit. For the present these are available only through our website, but we will be rolling them out in our eBay listings soon.
NOTE: We will continue to offer our original round-sectioned seals for the time being, as they are not only time-tested and cheaper, but are also somewhat easier to install. Though the new seals are more efficient, they must be installed in the packing compartment so that they are held snugly with no wiggle room. This may require reducing the outside diameter of the closure washer so that it can be seated all the way down against the seal. The older seals being round in section are much more tolerant of loose mounting.
