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Simple Leak Detection on Farm Equipment

Leaks are an unwanted visitor that will eventually affect most machines, engines, or drivelines. Not only are leaks unsightly but the escaping fluid attracts dust that finds its way into the system and can attack other components.

The first step is to identify the escaping fluid. The best method for this lies in your sense of sight, smell, and feel. Though color is a good indicator, depending on the location of the leak, the appearance may become skewed by mixing with dirt or another foreign substance. The smell, its lubricity, and consistency when rubbed between two of your fingers is highly accurate, though. 

More than one system can employ the same fluid. It is important to try to narrow that down to which fluid is leaking by washing the complete region with a mild water-based degreaser and letting it dry. 

Also, keep in mind that a leak can be affected by the wind (from traveling down the road) or the draft of a cooling fan. This movement can deceive you from determining exactly from where a leak is originating. 

start with a good cleanup

When I’m chasing a leak, I wash down the entire engine, transmission, or hydraulic unit. As an aside, when I wash a piece of equipment or a vehicle, I always clean the engine and undercarriage. I like clean equipment. It runs better and is easier to work. Plus, it alerts me to the beginning of the slightest of weeping.  

An excellent method to help identify a leak site is to employ a dye and black light. The dye is added to the fluid and the engine or the equipment is run. Then you use the black light to easily identify the problem area. Under the black light, the dye will produce an iridescent glow. A starter kit with a black light, dye, and safety glasses is offered by most larger auto part stores for around $60. Subsequently, all you would need to invest in is the dye (which retails for around $5 a bottle). There are dyes for petroleum-based fluids such as engine and hydraulic oil, coolant, and fuel. The fuel dye is especially good at identifying a leaking injector or line in a diesel that is diluting the engine oil. There are also dyes for air conditioning systems.

Most leaks are due to a loose sheet metal part (i.e., an oil pan, a hydraulic line that needs to be snugged, or a simple gasket or O-ring). The location of the leak determines the action required.

steps to stopping leaks

Sheet metal enclosures are sealed with a gasket and over many thermal cycles and through vibration, the fasteners relax. This is often a nuisance leak that first appears as an occasional drip. When you snug the bolts, do not overtighten them or you will warp the rail of the pan and compress the gasket and ruin it. Always alternate the tightening of the bolts and do not go around the perimeter at first. This pathway should be your final tightening sequence. 

Most pumps do not use any gasket but have perfectly machined mating surfaces for the joining parts. If the pump is leaking, the bolts are usually just slightly loose.

A hydraulic line may become porous from age and will only leak when the pressure in the system reaches a certain value. The same holds true for the lines used in an air conditioning system. Work the hydraulic system to raise the pressure to the upper range. When checking an air conditioner, temporarily block the airflow across the condenser (in front of the radiator) with a piece of cardboard and run the system at high idle for around two minutes with the hood closed. Shut the engine down and search for the leak with the black light.

If the rear main crankshaft seal appears to be the culprit, before you consider taking the engine apart, check the operation of the crankcase ventilation system. If weak or defective, the oil pan will become pressurized and push oil out of the rear crankshaft seal. 

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