Sealant cap assemblies comprise a cap shell having an interior volume and a recess adjacent to a bottom opening thereof, a sealant barrier ring at least partially inserted in the recess in the cap shell, and sealant located radially outside the sealant barrier ring adjacent to the bottom opening of the cap shell. The sealant barrier ring may retract into the recess in the cap shell. The sealant may be uncured or partially cured, and is prevented from flowing inside the barrier ring when the sealant cap assemblies are installed on fasteners. Methods of making and using such seal cap assemblies are disclosed. Fasteners sealed by such sealant cap assemblies are also disclosed.