Maintenance & Repair.

Importance of hydraulic system fluid level

Q. Some customers freely and almost boastfully admit that they seldom, if ever, check fluid level of their tractors' hydraulic systems. Instead, they wait until one or more of the hydraulic cylinders fails to extend to the needed length and

then add just enough fluid (often purchased from their local "discount" farm-supply store) to get as much extension as they decide they really need. How do we convince them that the owner's manual recommendations are NOT solely designed by the tractor manufacturer's engineers to increase sales of our more expensive factory-approved hydraulic fluid?

A. Maintaining the proper level of fluid in a hydraulic-system reservoir is not intended to be the ultimate objective of the process of periodic checking of the fluid level. Low fluid level is an early warning of future system problems if the cause of the low fluid level is not corrected. Adding fluid may cure the symptom and temporarily permit continued operation, but it won't cure the problem.

In some cases, the cause may be as simple as leakage around the rod seals of the loader cylinders, which is a relatively simple problem to correct. In other cases, the leakage may be internal to the system, requiring removal of hydraulic-system assemblies followed by bench testing to pinpoint the problem.

The importance of the system fluid is twofold. In addition to transmitting system force, it lubricates the working parts. Thus, if fluid level is inadequate during even a small portion of each operating cycle, severe and expensive-to-repair damage can soon result.

Thus, the lowest long-term operating costs will be achieved by each of your customers by having you: 1. Do a complete hydraulic system diagnostic test on each tractor that requires periodic fluid replenishment; 2. Repair or replace any components found to be malfunctioning; 3. Drain and flush the system of existing fluid; 4. Service the system filter(s); 5. Refill the system with fluid approved by the tractor manufacturer.

If your customer objects to the cost of this approach (a very possible reaction), compared to the cost of periodically topping off with "will-fit" fluid, point out that continued topping off only delays the day of reckoning, when a much more expensive complete system overhaul will be required to restore the system to proper operation.

Battery care is crucial

Q. Last autumn, we sold one our "regulars" a replacement battery for his self-propelled combine. Recently, after considerable sub-zero weather here, he stopped in and was voicing unhappiness with our "high priced" battery. It had frozen and burst its case while still in the combine. In contrast, his tractor battery, purchased a year ago from a local discount store, had survived with no damage and had "started the tractor engine every day" for chore use of the tractor. How do we explain to that our battery is not inferior to his lower priced "discount-store" alternative?

A. The temperature at which the liquid in a battery freezes depends on how well the battery is charged. Apparently, the left-in-place combine battery gradually self-discharged (a normal process) until its freezing temperature was equal to the air temperature. Whereas occasional use of his tractor during the cold weather months kept it charged well enough to prevent that battery from freezing.

Incidentally, this sequence of events is exactly the reason for the admonitions in operators' manuals to remove the battery from seasonally used equipment and store the battery in an area that will remain above freezing.

Adding front wheel drive

Q. Occasionally, we have customer inquiries that relate to the possibility (and advisability) of retrofitting front-wheel-drive to an existing rear-wheel-drive tractor. Typically, this would involve the installation of a "will-fit" kit advertised in one of the farm magazines. Usually the questions get around to the possibility of our doing the installation in our shop. We obviously have the necessary technical capability. But we become apprehensive, because after completion of the procedure, any problems the customer may have will probably be viewed by him as our (rather than the kit supplier's) responsibility. What are your thoughts on this situation?

A. My thoughts can be divided into two categories, technical and people-related.

Technical -- If the customer is willing to accept the complications of an extra drive line and extra universal joints on his tractor, front-wheel drive has advantages in some special situations. Primarily, it depends on the weight that remains on the front wheels when the tractor is placed under load. Often, in regular draw bar work, little weight remains on the front end. In this situation, driving the front wheels is of limited benefit, unless of course, an appropriate amount of front weight is added.

For loader operation however, the situation is usually more favorable. When the bucket is loaded, much of the normal rear-wheel weight is transferred to the front wheels. In this situation, it is definitely an advantage to have the front wheels powered.

People-related -- Here, your misgivings about future perceptions of the customer may be well taken. Obviously, your first step would be to discuss this aspect of the situation with the customer.

Then I would suggest that, as a minimum, you draw up an informal memorandum of agreement that both of you sign, and receive copies of, before accepting the project. If, at that stage, you have any misgivings whatsoever about this project, I strongly recommend that you consult your attorney for recommendations on how to proceed to safeguard your interests while hopefully not alienating your customer.

Breaking in the engine after an overhaul

Q. Frequently, after a tractor-engine overhaul involving new piston rings and cylinder sleeves, the customer asks if the best way to break-in the new parts is to let the tractor stand and run at idle for an extended period of time. What are your views on this practice?

A. Not a good idea. The rings and cylinder sleeves may well be damaged because of not receiving adequate lubricating oil. A better way is to put the tractor under partial load with the tractor engine operating at rated speed to assure adequate lubrication to the new parts. Partial load should then be obtained by downshifting one or two gear ratios below what would normally be used for the job being performed.

Engine oil filter's true role

Q. A few of our (older, more conservative) customers still profess to believe that the presence of an engine-oil filter on current and late-model tractors should allow them to safely extend oil-change intervals beyond those contained in the operators' manuals for their tractors. We know this is not a good practice, but some continue to see that information as only a clever plan designed to help us dealers sell more factory-approved engine oil. Can you help us explain (in non-technical but still technically accurate terms) to these "hold-outs" the fallacies of their views?

A. First, let me say that as a once-upon-a-time farmer and later a new-product development engineer with a major tractor manufacturer, I can understand their "wishful thinking" but at the same time am appalled that any equipment owner would be willing to risk the literal lifeblood of such an expensive (and typically vital to his operation) piece of equipment in any attempt to save insignificant sums in their total cost of operation.

In any event, filters are not, and never were, intended to extend the drain period of engine oil. Instead, they are designed to maintain the quality of the oil between normal oil changes. Thus, it can be said that the filter makes the engine -- not the oil -- last longer.

Melvin Long's career includes new-product development for John Deere and hands-on management of a 600-acre family farm. He has also done extensive editorial work on agricultural equipment subjects, including a book on hydraulic system diagnostics. In retirement, he tackles technically-oriented projects.