Back when I was working at the local turf farm, about 20+years ago, I was the mechanic that kept several balky old machines running, including an old international forklift, and a ford 3000 sod harvester(Brower), the boss lady had a "mechanic" on call, second guessing all of my conclusions. I would say bad hyd pump, and he gets a call. No flow meter, he tells by "feel"... I told the boss, call the ford dealer, and get them to come out and check with their flow and pressure tester. Guess who was proven right...
Another time, this guy decides to do an in frame overhaul on the crappy diesel motor (english ford). I decided to have some fun with him, as he was underneath, "feeling the crank", for wear, every once in a while, I would surreptitiously drop a piece of ball bearing, piston ring, or other misc iron part, down through the piston holes, right into his face... Had him scratching his great wooly head, for about 4 hours, that day.
when working on a loss of power steering problem, on the IH forklift, I stopped by the IH dealer, and found in their files, a recall letter, that mentioned a burr that developed in the valve bank, and I suggested taking a break cyl hone, to it, to de-burr that particular valve hole, and viola, as the french say, he "comes up" with the same advice. OK, he steals my ideas, and overcharges her for his work, its war now, I says to meself...
So one day she calls him to put a new starter rope, on an ancient arctic cat snowmobile, that she knew I wouldn't work on, cause I knew it had a bad carb, and wouldn't start, anyway(that particular carb, and kits were NLA, from the dealer...). Anyway, I saw him take off the 16 or 18 bolts, that were in the housing, watched him thread the rope around the starter spring assembly, and re assemble the 16 or 18 bolts back to tight, on the shroud in question. As he is tightening up the last bolt (I could have told him my next observation, at bolt # 1, but chose to withhold my advice, per HIS instructions), I ask him, "Shouldn't the rope, go through the grommet and not under the shroud?" He stopped coming around, and the old junkers were much better for it...