MOTHER'S HANDBOOK

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How do the hydraulics come into play? Well, if the stone gives up as easily as the one just described, you won't need them. In many cases, though, you'll find that the tractor's wheels begin to spin before the stone surrenders its grip on the soil. There's no easy solution to that problem if your tractor isn't equipped with hydraulics. If it is, however, you only need to back up until the drawbar is as close to the rock as possible, refasten the chain to eliminate any slack, and raise the lift arm a few inches. That serves to raise the stone slightly, transferring some of its weight to the drive wheels-the same idea as placing some cement blocks or a bag of sand in the back of a pickup truck for better traction on slippery wintertime roads.

I've gotten ahead of myself, though. Pulling stones is more properly a topic for Part II of this article, which will deal with some of the specifics of safe and efficient tractor operation. But having brought the subject up, I should go on to caution you that there's such a thing as too much traction. Attempting to pull too heavy a load with too heavy a hand on the throttle and the drawbar raised too high can cause a tractor to pivot on its rear axle and flip over backward-with perhaps fatal consequences for the operator.

Selecting the Right Tractor

ne aspect of choosing a tractor that probably isn't particularly important, except as it relates to the availability of good service or spare parts, is the manufacturer's name painted on the side of the machine. Most of the firms around today produce, and have produced, good and reliable tractors. So don't pay too much attention to the nameplate, but do concentrate on the features offered.

And what are those features? Foremost among them is horsepower. If you delve into tractor manuals, sales brochures, or other references, you'll notice that two horsepower ratings are usually given for each machine. PTO horsepower is the higher value, and refers to the energy output available at the power take-off when the tractor is stationary-the power available, in other words, for operating water pumps, generators, and other accessories. (PTO horsepower is sometimes called belt horsepower, since stationary implements driven by older tractors often ran on a flat belt-and-pulley arrangement, rather than on a drive shaft coupled directly to the PTO.)

Drawbar horsepower, typically 10% to 15% lower than the PTO horsepower, measures the pulling force available at the drawbar when the tractor is in motion. It's less than the PTO horsepower-which, roughly speaking, is the total output of the engine-because some power is consumed in wheel slippage and in moving the dead weight of the tractor itself. Drawbar horsepower is the more commonly used power rating, so all the recommendations I'll be making here are based on it.

For all-around use, a tractor of 25 to 30 horsepower is a good choice. If you'll be doing mostly heavy work, however-such as large-scale rotary tilling, mowing brush, skidding logs, or plowing heavy clay soil-a 35-horsepower model is even better. In any case, I feel that there's little point in opting for anything with less than 20 horsepower unless, of course, you're looking for a machine that will only be mowing the lawn and maintaining a onefamily garden.

If a small landowner is interested in purchasing a used tractor, a gasoline-powered vehicle is probably a better choice than a diesel. Gasoline engines run at a much lower compression than do diesels, which means that they tend to age more gracefully. It's easier to get gasoline than diesel fuel, and it's convenient to be able to fill your tractor, lawn mower, and tiller-and, in a pinch, your car-from the same fuel container. New diesel engines, on the other hand, are remarkably trouble-free-but when you're dealing with one that's 25 years old, problems are a lot more likely to crop up.

Virtually all tractors manufactured within the past ten or fifteen years are of the widefrontend type (Fig. 9)-that is, the front wheels are spaced as far apart as the rear ones. Before that time, though, tricycle-type tractors were more popular. In the tricycle design, the two front wheels are placed very close together or are replaced by a single wheel (Fig. 10). Both types have their advantages and disadvantages. In older tractors not equipped with power steering, the tricycle configuration made turning easier by giving the steering increased leverage against the wheels. Tricycle tractors were-and are-considered good choices for row-crop cultivation, because there's no wide front axle to interfere with forward visibility at ground level.

A disadvantage of the tricycle design is that it does not steer well on slippery surfaces or on light, sandy soil. Under those conditions, the closely spaced front wheels often skid sideways when turned, rather than biting in and bringing the front of the tractor around as they should. Of greater concern is the fact that tricycle-type tractors are inherently less stable than their wide-stanced counterparts, and are more subject to a deadly sideways rollover when driven on irregular or sloping terrain.

The decision in your case should be based on where you will use the tractor, and what sorts of jobs you'll be performing with it. If, for instance, you'll be using your tractor primarily for making hay on flat or gently sloping fields, a narrow front end need cause you no anxie ty. A wide front end is a better and safer choice for use on rocky or irregular ground, or if you plan to venture into the woodlot to move logs or firewood. Many older tractor models were manufactured in both a tricycle and wide-front-end version, so if you're responding to an ad for a used implement, be sure to ask, if the front end type is not specified.

Finally, consider hitch and implement compatibility. Earlier, in discussing hitch types, I implied that all hydraulic-equipped tractors utilized the three-point-hitch system. I was simplifying things a bit. The three-point linkage is now the industry-wide standard, but in the past many tractor manufacturers incorporated a hydraulic lift system of their own design, such as Allis-Chalmers' Snap-Coupler hitch and the Farmall Fast Hitch. Those and other designs required matching implements, usually manufactured by the same company.

It's just possible that you'll find a tractor with such a nonstandard hitch already equipped with every implement you need and that you'll buy the whole outfit at once. If, as is far more likely, the attachments don't accompany the machine, you'll probably want to continue looking or adapt the existing hitch to accept the more widely available three-pointhitch implements you're bound to acquire later. That's not necessarily a severe problem. Conversion kits are readily available to fit most tractor makes and models that require them. (Sears, Roebuck and Company is one source of hitch adapters-check its farm and ranch catalog for details. Another is the Central Tractor Farm & Family Center, P.O. Box 3330, Des Moines, IA 50316. Central Farm also sells a good guide to used tractor models, Farm Tractors 19501975, for $17.25 postpaid.) Still, the kits aren't cheap. Prices range from $200 to $600-and that amounts to a stiff jump in the price of the tractor. Sometimes it will be worth it, sometimes not.

When taking a tractor-particularly a used one-for a test run, think about the same things you would when buying a car. You want a machine that runs well and is in good condition mechanically. Scratched paint, rust spots on the sheet metal body, dents and dings in the fenders-none of these have much bearing on how well the tractor will perform. The following checklist includes some of the most important points that do have a direct bearing on performance:

[1] How are the tires? Front tires for the size tractor we're talking about run $50 each, or thereabouts, while new rear tires will set you back $150 to $250 apiece.

[2] Check the brakes. Unlike the brakes in your car, which are designed to keep you from running into things, tractor brakes are primarily an aid to steering, so each rear wheel will have its own brake pedal. Brakes that grab unevenly are a sign of bent drums, while squawking brakes probably need new shoes. Oil or grease leaking from the brake drums could point to more serious (and expensive) trouble.

[3] The engine should start easily and run without coughing, misfiring, or otherwise misbehaving. Thick, blue or black exhaust smoke probably indicates that the engine is badly worn and needs rings, valves, or both.

[4] Check the hydraulic fluid dipstick-which is usually located near the back of the tractorand the crankcase oil dipstick, which will be up front on the side of the engine. Dirty oil is a sign of poor maintenance, as is cloudy hydraulic fluid.

[5] Stand next to one of the back wheels and push in on the top of it, then pull outward. If you detect a significant amount of play, the axles and hubs are probably worn and may need to be replaced. That will cost several hundred dollars.

[6] Look under the tractor for oil or hydraulic fluid leaks. All old tractors drip a little bit, but excessive leakage should give you pause.

[7] Engage the PTO by stepping on the clutch and switching the lever near the driver's seat. It should turn steadily and smoothly-a grinding noise is bad news.

Just about all recently manufactured tractors utilize a 6-splined PTO shaft 1-3/8" in diameter, and that's the size that most PTO-driven implements are designed to accept. Some older.tractors, though-notably the Ferguson T020 and T030, Ford 9N, 8N, and NAA, and several other Ford models manufactured until the mid-'50s-came equipped with smaller, 11/8" shafts.

Adapters to step those slimmer shafts up to the now-standard 1-3/8" diameter are inexpensive and readily available. The adapters, however, often break when subjected to sudden stress. If you will be doing much haying or other demanding tasks that require the PTO, you'll probably want to replace the original shaft with a beefier 1-3/8" one. That's a surprisingly simple operation, but it will set you back about $100. (Be sure to buy a complete PTO conversion kit, rather than just a bare replacement shaft.)

[8] Raise the lift arms with some weight on them-if no implements are handy, you should at least stand on the drawbar-and leave them in the raised position for a few minutes. Occasional "hiccuping" is par for the course, but if the hydraulics can't keep the load up, or if it bobs up and down, the system is in need of an overhaul.

With the above information, you know enough to begin looking for a tractor of your ownand given some patience, common sense, and perhaps a little luck, you'll find the one you need. I'll be back next issue to go into some detail about tractor-drawn implements, safety, maintenance, and repairs

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