I would replace a panel like that because Federal Pacific is the manufacture that didn't design the electrical equiment to well.
Federal Pacific Electric Co. Stab-lok? Update
In 1983, the CPSC closed its investigation and stated that the data available to the Commission, at that time, did not establish that the circuit breakers presented a serious risk of injury to consumers. There was never an investigation of loadcenters.
by CPSC
From the early 1950?s through the mid-1980?s, Federal Pacific Electric (FPE) was a major manufacturer of circuit breakers and electrical distribution equipment. Early on, FPE introduced Stab-lok? residential circuit breakers and loadcenters. The heart of the Stab-lok? circuit breaker was automatically manufactured and calibrated; this mechanism was independent of the insulating enclosure; there were no screws to adjust and the stabs provided a low watt?s loss firm connection to the loadcenter bus. Several hundred million circuit breakers and the millions of loadcenters have been installed over the years.
FPE Stab-lok? circuit breakers and loadcenters can still be found in millions of homes. But, FPE didn?t just fade away. Even though FPE hasn?t made a circuit breaker since 1986, certain assets including the circuit breaker operations were acquired by other companies. Therefore, listed and labeled replacements for Stab-lok? circuit breakers continue to be available. In the U.S. UL listed Stab-lok? circuit breakers can be obtained from the American Circuit Breaker Corporation. Telephone 1-800-343-1910.