A lot of combines will likely face mud this year and that will strain drive components.
Add-on parts can make it easier.
A rear-wheel drive assembly can be put onto many models. It is expensive, but it works well.
Farmers who have never driven a combine equipped with a rear-wheel drive assembly will have to be careful. The change splits oil flow from one pump into four motors instead of two, so it requires travel at half speed in the field.
However, if you go on the road and switch it off, you’ll be thrown back against the seat as the machine takes off. If you switch it back on while travelling at road speeds, they will have to scrape you off the windshield with a spatula.
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The changes require oil to be added to the system. If the units came from an unfamiliar source, try adding the oil from the bottom of the system, such as the case drain plug in the hydrostats. That’s how they do it at the factory.
Duals can also be installed in the front axles, but be careful that the final drives can handle duals.
Even with the heavy duty drives, there are precautions to make sure they will last.
Change the oil before you start to combine and again in the middle of harvest. Oil is cheaper than gears and bearings.
The heavy load will produce grindings, which will produce more grindings, so get rid of them early if you want your system to last.
Check the teeth on these gears after harvest. If you find cracks starting along the length of a tooth, it’s metal fatigue. This happens when the gear has been overloaded. Make repairs before next year’s harvest.
If you are using duals, do not overuse the turning brakes. This strains the final drive. If you took the wheels off, make sure the hub bolts are properly torqued.
New bolts should be torqued to specification every hour for the first day and once a day after that until it won’t move when brought to torque specification.
The hydrostatic pump and motor need special attention. If I had a combine, I would hang a gauge in the cab window attached to the high-pressure port on the pump. The pressure should not be crowding or close to the relief valve pressure.
Some of these high-pressure relief valves can start leaking a little as they get close to their setting. In ordinary conditions, that might never be a problem.
Do not trust the books to tell you what that pressure is. Test it yourself and then operate below that level. When in doubt, change the valve. Keep a spare on hand.
Incidentally, reverse and forward are the same so if you are stuck, you can switch them.
Caution: you are dealing with 8,000 pounds per sq. inch of pressure. It’s enough to kill you. Operating pressure can lower by selecting a lower gear. Always operate in the top half of the pressure region.
One owner told me he put his tires on backward so he could always back out of any mud hole. I don’t know about that, but I know for sure the tires are a lot quieter on the highway running backward.
When changing wheels, use a two-wheel cart to line up the bolts. Put it under the lug on the side you want to lift and pry up.
Have fun and avoid the potholes.
P.S. You. Yes, you there in the rubber boots. Take that extension kit off your hopper.
Henry Guenter is a former service manager for Massey Ferguson. Contact: insidemachines@producer.com.
