Situation No. 1
Somehow, the coffee shop discussion turned to brake fluid on a hydraulic system. You state there is no need to change it unless you open the system by removing or loosening a connection. You ask the others what they think, and this is what you hear:
A: Farmer A states that even though the system is closed, it will wick in moisture and so it needs to be changed.
B: Farmer B agrees with you and brags that he never changed the brake fluid in any vehicle he owns.
C: Farmer C believes the old fluid needs to be changed, but the ones used in the past 30 years are lifetimers.
D: Farmer D says if it looks clear, it is good. Only change it when it gets dirty.
Situation No. 2
You ran over something in the road, and now your gasoline-powered pickup has an exhaust leak – and the next day, the “service engine soon” (SES) light came on. You went to one of the large auto parts stores in the next town that reads computer trouble codes for free. They said the code is for “mixture lean” and that you need a new oxygen sensor. You buy one from them for $135, and when you get back to the farm, you install it. You now go back to the store to get the code erased. On the way back home, the SES light comes on again. You turn around and go back. The store clerk tells you it is the same code and shrugs his shoulders. You ask some other farmers, and they tell you this:
A: Farmer A says the sensor you purchased must be defective.
B: Farmer B believes that since the code is for a lean mixture, the exhaust leak must be near the sensor and is pulling in oxygen. The mixture is not lean.
C: Farmer C tells you some wires are broken.
D: Farmer D thinks there is something wrong with the engine.
Situation No. 3
You are tired of losing power at the home farm, so you invest in a PTO-operated generator to run the house. You went this route since it is on a wheeled cart, and you can also use it anywhere on the farm. The unit has a voltmeter and, according to the directions, the PTO needs to run at 540 rpm. When you set the tractor’s throttle for that speed, the generator only produces 108 volts. When you raise the engine speed so that an indicated 650 to 675 rpm is read, the output of the generator is at 120 volts. The company that made the generator says it is designed to produce 120 volts at 540 PTO rpm and the tachometer on the tractor must be wrong. You agree but wonder how to check the tachometer for your own knowledge.
A: Farmer A says you need to invest in a simple photo-optical tachometer. It can be used to confirm the PTO speed versus the tachometer reading.
B: Farmer B says there is no way to confirm the PTO speed, and he often wondered about his tractor.
C: Farmer C tells you to buy a new in-dashboard tachometer and see if it is the same.
D: Farmer D believes you can do it mathematically if you know the gearing in the transmission.
Answers
Situation No. 1: Farmer A is correct. The system is closed, but over time and under-hood thermal cycles, moisture will collect in the brake fluid, so it does need to be changed. There are test strips and, for those willing to make the investment, a meter to read the moisture content. Moisture-laden brake fluid will lower the boiling point and cause pitting and corrosion and eventual failure of the hydraulic components.
Situation No. 2: Farmer B is correct. The exhaust leak is near the oxygen sensor, and fresh air oxygen is being introduced into the pipe, skewing the sensor reading. With electronic fuel injection (EFI), this is an issue, since the mixture will be driven rich to compensate for the false reading. The result will be engine oil dilution and washing of the lubricant from the cylinder walls.
Situation No. 3: Farmer A knows his stuff. Every farmer should have an inexpensive photo-optical tachometer (under $100). It works with a piece of reflective tape. Place a small piece of tape on the PTO (or anything else that rotates), start the engine and engage the PTO. Point the optical tachometer at the PTO shaft and read the rpm. Compare that to the tachometer.
