A system for mounting an internal fuel manifold within a gas generator case of a gas turbine engine includes at least one fastener support assembly having a fastener pin and at least one receiving element, respectively engaged to either the internal fuel manifold or the gas generator case. A biasing member is located between the fastener pin and the receiving element to axially preload the joint between the fastener pin and the receiving element, such as to constrain relative movement between the two parts in an axial direction while allowing relative movement in a radial direction.