Farmall Super C oil level petcocks frozen shut

[aka nick]

Hi everyone. I am new here and have a new to me Super C that I am trying to make some simple repairs to. One problem I have is the petcocks for the oil level are broken. Any suggestions on how to replace them? I have the new parts but can't seem to break them loose and the valves are jammed tight so I have no way to open and check the oil level.

I'm open to some one who has an idea.

 

[DJ54]

The originals have left hand threads, so you need to turn them CCW to check the oil, if there is enough left to get a set of vise-grips, etc. on.

To replace the complete petcock, a small enough pipe wrench to get hold of it backs them out. There is a threaded insert on the inside of the oil pan they thread in to.