Richard C.- I wonder about the long term durability of the carbon plugs. Cost of copper is "relative". Relative to WHO You know and what You want. I used to be able to easily get brass bar ends from My screew machine shops. I should have gotten WAY more than I did. Steve B is exactly right about the relationship to welding & grinding. I never try to "drill" weld metal, I have solid carbide rotary burrs for removing excess metal, and most times less weld is better than MORE weld. I have a lot of welders and even MORE grinders, a 7"/9" elec angle grinder, three 4-1/2" angle grinders, three or four air die grinders, a elec. die grinder, three Dremels, and three bench grinders. I used to work for the parent company of Porter-Cable/Delta and 2-3 times a year they'd have tool sales. I wasn't the plant's BEST customer but I was always in the top two or three.
Steve B. does very high quality work on the projects I've seen. I really like what He did to His snow blower with the lights & higher intake.
TOM S. - Your internal brake acts on the lower trans shaft that the pinion that turns the differential is part of. That means You're braking action also runs thru the diff. You can still have one wheel turn freely one way while the other wheel turns the opposite way. If You're brake isn't hung-up then I'm afraid You have more serious transmission and/or differential and rear axle issues. Robert H's diagnosis, even though it's His First post is 100% correct. I think with the 7:1 reduction thru the reduction gears You can turn the input shaft over the resistance of the brake, but trying to push the tractor Your trying to turn the brake Faster and that's why it skids the tires. My $0.02.....
MATT S. - The grooves worn in You're axle pivot pin where probably not lined up correctly with the holes in Your tractor frame. That's why it came out hard. Buy or make a new pivot pin. Anything You do to get grease to the pin will help it last a LOT longer. IH drilled for a zerk in the axle casting, every tractor I've owned has had a zerk on the back side of the right end of the pivot. The axle is supposed to pivot on the pin, appears Your pin pivoted in the bushings on the axle mount. Also, Mike F. is correct, IH used a "LOT" of press-in zerks in assembly, Guess how I know, and also how many I installed when I worked subassembly on WFE axles @ FARMALL? Pull the spindle out of the end of the axle, clean everything up, take a small punch and lightly tap the broken end THROUGH to the inside of the axle, then You can either try to gently tap a new press-in zerk in or drill & tap 1/8" NPT threads and install a regular zerk.