An across-the-line cap ought to be replaced with an X2 safety cap, designed to fail open rather than short.
Sal's and
Just Radios have them, as well as other sources. X2 for across the line, Y2 for line to ground. There is also a cap rated X2Y2 for either use.
http://www.tuberadios.com/capacitors/
http://www.justradios.com/