Agriculture Reference
In-Depth Information
Do the hydraulics work without leakage or letdown?
Extend the hydraulics, paying at-
tention to whether they operate smoothly or chatter. Lift an implement with the hydraulics
and see if there is any loss of lift power over a few minutes. If the implement starts lowering
on its own, the hydraulics require attention.
Is the tractor structurally sound?
Look at the frame and all steel and cast components
for obvious cracks or hairline cracks.
Does it look like all moving parts took grease during the life of the tractor?
Look for
the presence of excess grease around moving parts.
Do the zerks (fittings) still take grease?
Or are they clogged with dirt, and are the joints
“frozen”? Try to add grease to the zerks with a grease gun. Manually or with tractor power,
manipulate joints to see if they move freely.
Do the tires have deep cracks or fissures in them?
If so, beware: the tires could come
apart at any minute.
Does the age match the hours and the serial number?
If the number that appears on the
hour meter doesn't jibe with the stated age and serial number, ask the seller to verify.
What is horsepower?
Horsepower is defined as the amount of energy or work required to raise a weight
of 33,000 pounds a height of 1 foot in 1 minute of time or to overcome or create a
force that is equivalent to doing that amount of work. Therefore, in simplified terms,
horsepower is 33,000 foot-pounds of work done in 1 minute. Tractor manufacturers
represent horsepower in various ways. Some rate their equipment with the horsepower
rating of the engine, but this doesn't take into account that the energy must be trans-
ferred through the tractor's drive train to the wheels or PTO in order to be used. Oth-
er manufacturers use laboratory tests to take horsepower measurements, but often the
tests are not “real world,” so the value can be inaccurate.
A useful measure of how much work a tractor can perform over a long period of
time is sustained or continuous horsepower, measured by a dynamometer. To test a
tractor's pulling ability, its wheels are rested on the dynamometer platform and the
tractor is operated at varying speeds in all gear ranges against standardized resistances.
The performance is then averaged, and the resulting pulling capacity is known as its
drawbar horsepower, or how much power the tractor can continuously deliver to the
drive wheels. In another test, the dynamometer is connected to the tractor PTO and
the engine is operated at various speeds against standard resistances. The resulting av-
eraged value is known as the PTO horsepower, or how much power the tractor can
continuously deliver to an auxiliary piece of equipment through the PTO.
PTO horsepower = 75-85 percent of engine horsepower
