Nobody has every tool they need for every situation. Professional mechanics often improvise or substitute to get jobs done, and I know for a fact (because I've done it myself back when I farmed) that farmers are very adept at adapting. For example:
-a short 2 x 4-inch or 4 x 4-inch wooden block makes a functional seal or bearing driver. Wood blocks also work well to prevent damage or "mushrooming" the end of a metal shaft if it's necessary to use a sledge hammer to, uh, "persuade" the shaft.
-SnapOn, Mac and other tool companies sell fancy punch sets designed to remove bearing races. Envision a long cold chisel with the tip flattened rather than sharpened, so the user can catch the edge of a race to drive out that race. So...rather than pay $50 to $100 for those special punches, why not take a couple old cold chisels and carefully grind the tips flat, or oval, and get some race-drivers for free?
-If it's necessary to drive a bearing, bearing race or bearing seal below the surface of a component, after you use a 2 x 4 to drive it "flush" with the surface, select an appropriate-sized regular 1/2-inch drive socket to seat it below the surface. Standard socket sets up to 1 1/4-inches, combined with 3/4-inch drive socket sets that go to more than 2-inches, provide a range of sizes that work well to seat bearings, bearing races and seals commonly used on farms. Don't hit the socket directly with a hammer---use that wooden 2 x 4 to protect the end of the socket from being marred by hammer blows.
-When precise internal measurements are required in places where it's difficult to position a ruler, micrometer or caliper, use drill bits as "go/no go" gauges. If the minimum gap between two drive sheaves is supposed to be 1/8-inch, use a 1/8-inch drill bit to adjust the clearance until the drill bit just barely fits between the sheaves.
-Big cardboard boxes aren't actually a "tool", but they make wonderful accessories when working in awkward, potentially painful locations. If you have to lean against sharp edges to make repairs, or kneel on gravel, even a small piece of cardboard can make a big difference. If you have to work inside a combine, laying on top of straw walkers, a sheet of cardboard is almost a necessity. Just be sure to remove the cardboard from the strawwalkers after repairs are finished.
(FYI--sheets of cardboard make a horrific sound if they go through a straw chopper when the machine is test-run, and it takes a long time to clean up the shredded confetti...)