Abstract: A process for repairing leaking glass-to-metal seals of a hybrid microcircuit header. The process comprises the following steps. A leaking hybrid microcircuit header is delidded (has its lid removed). The leaking hybrid microcircuit header, generally with its leads pointing vertically, is disposed on a vacuum source. A vacuum is formed on the hybrid microcircuit header using the vacuum source. A stream of helium is flowed over the seals to verify the presence of leaks in the seals of the hybrid microcircuit header. A small amount of high vacuum sealant is applied to each of the leaking glass-to-metal seals while the hybrid microcircuit header is exposed to the vacuum. The vacuum draws the sealant through the cracked or defective glass-to-metal seals. The high vacuum sealant generally comprises a silicone resin having a low vapor pressure. A stream of helium is caused to flow over the resealed leads following application of the high vacuum sealant to confirm that the hybrid microcircuit header is sealed.