A 60A circuit breaker carrying 53A should not be 'red hot'. Quite warm, perhaps, but not red hot.
I would check very carefully for damage to the bus stabs, or damage to the end of the conductor, both of which could cause a high impedance connection and localized heating. Was the breaker correct for the panel, or one that 'just happens to fit'?
If you have a high impedance connection, then it will heat and trip a new 70A breaker just as it did the 60A breaker.
-Jon
