In Reply to: Front Main Oil Seal Replacement on '49 8N posted by 8N Tractor Guy on January 24, 2020 at 20:13:49:
It's been a while since I last did a rebuild, but if I remember correctly, the O.D. of the seal fits into the grooves in the timing cover and oil pan.
To install the 1-piece seal without removing the timing cover, the main bearing caps have to be removed to allow the crankshaft to be lowered enough to install the seal.
The oil pan needs to be dropped to replace either type of front seal.