Rider 3-58 Model 54 Replaced caps #31 (2) used a .0001 at 500 volts Silver mica. Is 500v's large enough? Radio played good then started buzzing, maybe another problem started?

:Rider 3-58 Model 54 Replaced caps #31 (2) used a .0001 at 500 volts Silver mica. Is 500v's large enough? Radio played good then started buzzing, maybe another problem started?
:

:Rider 3-58 Model 54 Replaced caps #31 (2) used a .0001 at 500 volts Silver mica. Is 500v's large enough? Radio played good then started buzzing, maybe another problem started?
:

:Rider 3-58 Model 54 Replaced caps #31 (2) used a .0001 at 500 volts Silver mica. Is 500v's large enough? Radio played good then started buzzing, maybe another problem started?
:

::Rider 3-58 Model 54 Replaced caps #31 (2) used a .0001 at 500 volts Silver mica. Is 500v's large enough? Radio played good then started buzzing, maybe another problem started?
::
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500 V is more than adequate. The radio can't generate anywhere near that voltage in the audio circuit in which these caps are used.

However, 0.0001 uF is rather low for an audio coupling cap. A 0.02 uF cap for the audio coupling cap would have been more appropriate. What were the original values used in the set?

Did you ground the plate bypass cap to the radio's ground bus, as it was originally wired? If you grounded it to the metal chassis, you could have hum pick up.

Component lead dress is important in this stage, too, since the high-gain audio amp will readily pick up AC hum from the heater wiring if a component on the grid circuit is too close to a line carrying AC.