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Mechanics Corner: Fighting the bad connection battle

Andy Overbay for Progressive Forage Published on 09 June 2017

Today’s tractors and implements are truly amazing. Drones and GPS guidance systems, auto steering and implements that tell the tractor to speed up or slow down.

With all of that mechanization, automation and convenience also comes a good measure of complication as well. A young farmer shared with an audience just a few days ago that he used to pull the planter out of the shed, grease the bearings, check the chains and have at it.



This past season, it took him two hours to download the updates for the planter before it could plant the first kernel.

Even if you don’t have a piece of equipment that modern and complex, it is easy to understand the frustration of a farmer when these expensive quantities of iron fail to perform to the expected level or fail to operate at all.

While system failures can be difficult to diagnose without the help of a factory-trained mechanic with up-to-date tools, it is also good advice to check the simplest things first. Not the least-common issue with technically advanced equipment can be bad connections and blown fuses.

It really comes as no surprise our modern farm machines suffer from connection issues. After all, most of our equipment lives under the very environmental conditions that adversely affect electrical flow. Dirt, dust, moisture, heat or vibration can singularly disrupt the flow of power and data in and around our machinery.

While there are several redundancies in the electronics of the modern tractor, sometimes safety overrides can produce issues in places that at first might seem unrelated. For example, my own tractor was shutting off its PTO every 20 minutes while we were baling straw a decade ago.


If we shut the tractor off and restarted the tractor, it would bale fine for another 20 minutes and then shut down again. Maddening. The culprit was a blown fuse in the speedometer. The computer was telling the tractor the PTO was running with the tractor in gear but standing still (as far as the computer could tell).

A part costing less than a dollar was holding up $100K worth of equipment. Needless to say, a lesson was learned.

Connection issues can be difficult to trace, but sometimes we can help ourselves most by taking a little time and being a bit neater. Layers of grime and dirt left clinging to the outside of housings, motor blocks, cables and wires act as insulators, holding heat in and taxing cooling systems and electrical connections.

A 1/8-inch layer of grease on an engine doubles the amount of oil and coolant it takes to cool that engine, so keeping it clean pays.

A little grease can be a good thing though – not regular lubricating grease but dielectric grease. Dielectric grease is non-conductive and silicone-based, and is designed to seal out moisture and prevent corrosion on electrical connectors.

It also disrupts the flow of electrical current, which makes it good for lubricating and sealing the rubber parts of electrical connectors. It’s commonly used in automotive spark plug wires, recreational and utility vehicles, and electrical systems in aircraft.


This material is a translucent, gray lubricant that does not dissolve in liquids like ethanol, methanol, mineral oil and water. It can be dissolved with methyl ethyl ketone and mineral spirits, however. Dielectric grease affects silicone rubber over time, so it isn’t always a good choice to use it on silicone-based O-rings or wiring harnesses.

It can withstand high temperatures, making it a good choice for engine compartments and similar locations. Many dielectric greases are rated to work in up to 392ºF (200ºC), and some can operate at up to 500ºF (260ºC). Although there are other greases that can work at these temperatures, they may not prevent the flow of electrical current like dielectric grease does.

Dielectric grease is widely used as a sealant for spark plugs in gasoline or diesel engines, as well as on the gaskets of multi-pin connectors in the electrical systems of vehicles and boats.

When used with spark plugs, it is applied to the rubber part of the plug wire. This helps the boot slide onto the plug’s ceramic insulator and keeps dirt or moisture from contaminating the seal and disrupting the electrical current.

Besides being used to seal rubber covers on electrical connections, dielectric grease also prevents corrosion when applied directly to metal connectors.

Although it works well for this purpose, it can sometimes cause a connection to stop working if not all of the grease is pushed out of the way between the points of contact inside the connector. Additionally, it is often used to lubricate other engine-related parts, like rotors, distributor caps and speedometer cables.

Silicone-based lubricants, including dielectric grease, can irritate the skin and eyes, so users should wear safety glasses and gloves when using it and promptly wash any skin or clothes that come into contact with it. At high temperatures it may create formaldehyde, which irritates the eyes and respiratory system.

Users of dielectric grease should consider the temperature conditions in which they need it to work, since some formulations are better for higher temperatures than others. Caution also needs to be used with these products around oxygen sources such as the torch in the corner of your shop.

It is very possible to ignite lubricants in oxygen-rich situations and, as you can imagine, slipping hazards are another concern when applying grease. Be careful and be clean.

Finally, it is very important to store equipment in the dry, and protect connections from moisture, especially in humid situations. It is wise to not use tarps as weather protection for equipment as a long-term solution. While tarps may keep rain and snow off your baler or other piece of equipment, they can also hold moisture close to the equipment and prevent the sun from drying it off.  end mark

Andy Overbay holds a Ph.D. in ag education and has more than 40 years of hands-on dairy and farming experience.