Broken Stud on Final Drive Inspection Cover - Suggestions?

[AlphaBob]

I'm trying to get the Final Drive Inspection Cover off my T133S - there are 12 studs with washers, lock washers and nuts. Naturally, after I wired brushed the exposed threads, soaked them with Kroil - penetrating oil and then used an impact wrench (possibly a bad idea), I wrung [broke] one of the studs off.
I'm hoping that the originals are pressed in from the back and I'll be able to apply some heat and punch out the broken stud. If they're welded in place, this might be a pretty good sized job to get it fixed. When I look a the repair / parts manuals they don't show the studs as a separate piece which suggests that they're welded into place - not good!
Better, I can't get the inspection cover off the unit - they are installed with silicone sealant and it won't pop off - been tapping the cover with a brass drift and worked the edges with a razor, but it isn't moving yet.
Any suggestions on either front would be appreciated.

 

[Coldheart]

The studs are welded using a gas shielded stud gun. It is ok to use a impact as long as the pressure is way down. The studs are a 5/16" x 3/4", or 5/16 ' x 7/8". When reinstalling torque nuts at 10ft/lbs. As to the silicone problem, all you can do is work away at it and it will come off.

 

[AlphaBob]

The studs are welded using a gas shielded stud gun. It is ok to use a impact as long as the pressure is way down. The studs are a 5/16" x 3/4", or 5/16 ' x 7/8". When reinstalling torque nuts at 10ft/lbs. As to the silicone problem, all you can do is work away at it and it will come off.

Thanks Coldheart - I'm now looking for someone local with a stud welder. There are probably other ways to skin this cat, but the stud welder will repair unit exactly like the way it was built.
Thanks for the response - I didn't even know that there was such a tool as a stud welder!
Next time (like when I do the other side), I'll be more careful!