MACHINERY
From page 25
bearings. If nothing else, loose
steering and wobbly front
wheels will prevent you from
ploughing or cutting in a
straight line.
If your proposed purchase, for
example a Vaaljapie, has a
single front axle pivoting on a
short shaft under the radiator,
check both the axle and shaft
for wear. With hard wear and
abuse the axle can crack
under the shaft. Check for
evidence of welding repairs.
Check the wheels, particularly
where the rims make contact
with the tyres. They should be
smooth. If they are bent
inwards they will place
unnecessary stress upon the
tyre walls. Check the condition of the tyres. They may be
worn, but are they cracked
and perished?
Remember that all the torque
that your tractor generates is
transferred from the tractor to
the ground through the tyres,
and effectively through the
side-walls of the tyres so it is
imperative to have a decent
pair of rear tyres at least. With
tractor rear tyres costing
upwards of R2 000 apiece,
and with some front tyres
difficult to obtain, having to
cylinder block or head.
Similarly, check the gearbox
and diff oil (there is often a
dipstick for these compartments, too). Old oil is likely to
have absorbed some moisture
All the torque that your tractor
generates is transferred from the
tractor to the ground through the tyres,
and effectively through the side-walls
replace them just after you've
bought the tractor can
become a costly affair.
Check the engine, gearbox
and diff housing and wheels
for missing bolts and broken
stubs. The older the tractor
the more likely that nuts and
bolts with the correct threads
will be difficult to purchase.
Remove the dipstick and
check the oil. It may be black,
and is likely to be so if the
tractor is a diesel model, but
is there any evidence of water
in the oil? This could result in
the oil/water mixture being
white – evidence of a cracked
and may thus be opaque,
rather that clear and golden.
Check the coolant fluid also.
How brown is it?
On dual-fuel (petrol-paraffin)
tractors, there will be a fuel
changeover tap. These are
invariably sealed with a cork
gasket, which often leaks
when old. While this is
neither difficult nor expensive
to replace, far more serious
are the leaks along the fuel
line to the carburettor.
Tractors that run on power
paraffin will have some
system for heating the fuel
before carburetion. On
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Vaaljapies, for example, this
takes the form of a thin metal
plate hot box bolted onto the
manifold, and covering the
carburettor.
If you find your tractor
without a hot box you should
not run it using power
paraffin, but should stick to
petrol (which is cheaper
anyway). However, if run on
power paraffin (if you can
find the stuff … remember it's
not the same as illuminating
paraffin) your tractor will give
you up to 20% more power.
Start the tractor. All diesels
smoke a bit on startup, so
don't be put off if you are
enveloped in a cloud of
exhaust smoke. As the engine
warms up, however, the
smoke should clear. If it
doesn't, it could be evidence
of a worn engine, although it
might be something less
serious such as dirty injectors.
A smoky petrol engine is
evidence of wear or maladjustment of the fuel mixture.
Continued on page 27