[esoxmagnum]

try Sea Foam Deep Creep. I’m a plumber by trade also HVAC/boilers (50 years just retired not long ago) and years ago we started carrying Deep Creep on our trucks. Works great on rusted pipe fittings, best thing we’ve used. Especially on boilers. Unless you can use a torch of course. I use it on my cars as well.

For cast iron pipes that wont come loose.... an apprentice and a sledge hammer work best.

[right way right]

Thanks I'll have to try it.
The acetone and ATF sounds interesting too.
I work a lot with pins on equipment too.
Heat applied correctly can save a lot of hassle at times.
Get the weldement bosses good and red and what ever you do don't mushroom the ends of the pins. Put on the hearing protection.