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Combine Maintenance: Inspecting the Cleaning Shoe

Inspecting the cleaning shoe is one of the dirtiest jobs of preparing a combine for harvest, Rodney Edgington admits. “Maybe for that reason, the shoe is often ignored,” the Successful Farming Combine Doctor believes. “Components in the shoe do wear out, and their failure can have a big impact on grain losses – let alone reducing combine capacity.”

Edgington offers the following five-step inspection guide that won’t make the job less dirty, but it will identify existing and future parts failures.

1. Pull the chaffers and sieves out of the back of the combine and examine them for bent or missing fingers.

“Bent fingers won’t let the element close or open properly. Missing fingers don’t clean grain. As you examine the fins, also notice where their rods (wires) operate in the frame and look for elongated holes.” Also, check deflector flaps and high-crop dividers to see if they are missing or damaged, he recommends.

“Pay particular attention to the frames themselves. Look for cracks, especially at the corners, and look for damage. You can weld cracks, if necessary. Your aim is to have solid frames; you don’t want the chaffer or sieve operating loosely,” he says.

Generally, any wear from operation will occur in the center of the front half of the chaffer, as this is where the highest amount of residue and grain flows in from the separator.

“Lay down a sheet of ¾-inch plywood on the cleaning shoe pan. You can break the rivets that hold the sheet metal to the frame by crawling inside,” Edgington points out. “With support from the plywood, crawl inside to inspect the side rails holding the chaffer and sieve frames.

Look for cracks and damage on the rails. Also, see if the rubber seals are making contact. Those seals can get packed full of debris, which, along with tears in the seals, allow grain loss on the side.”

2. Examine the tailings and clean augers and inspect their flighting for wear (edges that are sharp or rolled back).

Check to see that the augers are not bowing; this greatly diminishes their ability to move grain and leads to plugging. Bowed augers cause flighting to hit their bottoms and wears away the flighting and the sheet metal. “Make sure the drives are set correctly so as to avoid wear on bevel gears. Also, turn the auger by hand to determine if the bearings need to be replaced,” says Edgington.

Check that the front drive bevel gears for the augers are meshed correctly and their backlash is set correctly (not operating too loose or too tightly). “All augers have a bearing, and all need to be inspected. While you’re at it, look at the bearing collars to see if they have become loose and to check for missing hardware,” he advises.

3. Be sure to examine the cleaning fan.

“A lot of farmers think the cleaning fan is indestructible, but the fan’s fins can become damaged or break out, which compromises airflow in the shoe,” says Edgington. Remove the belt driving the fan and spin it, watching for trueness in operation while listening for bearing noise.

Pay particular attention to the belt on variable-speed fans, as they do become glazed and cracked with use.

4. Inspect all shaker arms by looking for bent arms or failing bushings (indicated by glazing or shininess).

“A bent arm or worn bushing can create vibration in the cleaning shoe leading to damage of the chaffer and sieves,” he says. Examine where the shaker arms are bolted to the framework to see if welds are cracking.

5. Take the drive belts off grain elevators and look for missing paddles and sagging chains.

Check chain tension and do so daily. Adjust tension so that paddles don’t sag backward in operation, which causes grain to cascade back down the elevator. “When turning the elevators, listen for bearing noise and look at the chain sprockets to see if their teeth are cupped, which indicates excessive wear,” he says.

Rodney Edgington: The SF Combine Doctor

Rodney Edgington has witnessed the wear and tear that harvest can inflict on a combine from the hundreds of harvesters he and his crew have inspected and repaired over the years. His company, Combine Specialties, services combines from across the High Plains out of the firm’s base in Ulysses, Kansas. You can contact Edgington at or by calling 620/521-2223.

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