I started with Massey Ferguson in 1972, the year that the first 750 combine came off the line and I left the company in 1989, the year that the last 860 was manufactured. A lot of them are still out there.
Here is information that might help keep them running for many more years.
For starters, the hydraulic reservoir should be filled with Permatran 111 or MF M1141. If it needs to be topped up, you can use Type A transmission fluid or Dezron 11. Type F is not compatible with the seals on that system.
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There is a screen in the reservoir that doesn’t need to be serviced regularly, but a major failure could occur if it gets a clot of iron filings in it.
Oil might occasionally foam enough that the system starts to react in a jerky manner. Check the return line. It should aim away from the intake line.
The pump, which sits in front of the engine, has the relief valve and the flow divider that gives priority to the steering. The first combines had only one steering cylinder on the back axle. The manufacturer then went to two cylinders and it slowed down the steering to about half speed.
Operators tried to steer faster than the system would allow and complained about hard steering. The secret was to ream out the hole down the centre of the hydraulic spool. You had to be careful because you were robbing this from all the other circuits. This becomes most noticeable on the header lift.
The first valve in the system is the header lift valve, which sits in front of the engine. It has a lot of plastic parts in it and when oil gets hot, some of them, especially the main header check valve, can also get hot and distort, causing the header to drop.
If this occurs, check the latest plastic check valve for the source of the heat, which could be produced by one of the following:
- Too small a motor on the pickup. To run the pickup at the correct speed, the adjustment would have to be set extremely low and the pressure would be quite high. The higher the pressure, the more chance of heating and the greater likelihood of damage to the valve.
- The linkage on the valve for the unload auger might be stuck. It usually happens when the operator has just finished unloading grain, brings the auger to the home position and doesn’t watch the lever to make sure it self-cancels.
If it sticks in that position, it will blow the relief valve until the plastic poppet melts. The brackets holding the shaft may not be square to the shaft. The spool could also be binding in the valve body because the mounting plate is not straight.
- The pump could be causing the oil to heat. Remember that any wear on any part of the system causes heat. This is especially true of the pump. Wear between the gears and the pump body is a typical cause of heat.
- There are numerous parts to consider when determining what causes oil to heat. In all these cases, a part that is supposed to hold tight does not:
r Relief valves set too low so they are constantly letting oil through.
r Bad seats on the relief valves.
r Leaking steering cylinder.
r Worn pick-up drive motor.
r Dirty oil cooler. You would be surprised what lurks in a poorly maintained cooling system.
You might find that the base of the header lift cylinders have expanded in a circle all the way around the base. It will happen on both cylinders at the same time.
For example, the combine was parked last fall in cold weather with the table all the way up and when the warm weather heated the oil, it had no place to go. When you park the machine for any length of time, let the header rest on the stops to take all the pressure off.
The header lift valve might also stop functioning, especially in the earlier models. It could be dirt.
Later on, the manufacturer put a fine mesh screen in the line from the pump, which solved the problem.
In an emergency, use the reel lift to raise the header if running a pickup.
If you take the whole valve apart to clean it out, be sure to change all the O rings.
When you put it back on the combine, you might find that with the lever in neutral, the header will go up as soon as you increase the engine speed, which is not what you intended. This is because you put the lift and lower orifices in the wrong place. They are both accessible from the outside, so just switch them.
Remember, the sooner you begin servicing your combine in the summer, the happier you’ll be at harvest.
