If the system maintains pressure throughout, the sole component you have yet to examine is the cap. When subjected to intense operation, it may become excessively hot, potentially causing the cap to fail under elevated pressure.
In any case, acquire a new cap. They are exceedingly inexpensive. However, I would refrain from purchasing a Febi product as the recent one I acquired from them was unsatisfactory. Preferably acquire an original equipment manufacturer Ford component.