Sep 18, 2014
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September 2013 Archive for In the Shop

RSS By: Dan Anderson, Farm Journal

As a farm machinery mechanic and writer, Dan brings a hands-on approach that only a pro can muster. Along with his In the Shop blog, Dan writes a column by the same name as well as the Shop Series for Farm Journal magazine. Always providing practical information, he is a master at tackling technical topics and making them easy for all of our readers to understand. He and his wife, Becky, live near Bouton, Iowa.

A Different Angle For "Opening" Fields

Sep 28, 2013

 When harvesting row crops, there comes a time when opening fields that it's often convenient or necessary to harvest across the endrows. This puts tremendous stress on harvesting heads, especially soybean platforms.

Cutting perpendicular to the rows forces the sickle to go from "no load" between rows to total load across the full length of the cutterbar in a split second. On a 24-row headland, the sickle has to absorb that shock load 24 times in only 10 or 15 seconds. A soybean platform in good mechanical condition will probably handle the abuse without damage, but a platform with a worn sickle or drive could fail under the rapid changes in load. Typical consequence is a broken sickle or snapped drive belt halfway across the headland--or halfway down the headland or into the field as damage that began on the headland finally reached critical mass a few acres later.

Corn heads are a little tougher than cutterbar systems, but the shock load of 8 rows of Bt-corn stalks supporting 180 bu./ac. corn has been known to cause aged or worn corn heads to shear gears or make slip clutches rattle.

To avoid shock loading harvesting equipment when harvesting "across" rows, turn the combine slightly or drive in a slight curve so that each row doesn't encounter the cutterbar or gathering components all at once. 

Use Electrician's Tape To Install Seals

Sep 22, 2013

 'Tis the season to replace bearings in gearcases and housings, and that often includes replacing a rubber-lipped seal on the bearing's shaft. Many shafts have half-moon keyways or slotted keyways machined into them. The edges of those keyways are often sharp enough to slice the spring-loaded rubber lip of seals as they are slid onto the shaft, creaking an immediate lubricant leak from the brand new seal.

One way to minimize the chance of cutting a seal's lip during installation is to carefully wrap the shaft with electrician's tape before installing the seal. Just one layer of tape will protect the seal's rubber lip from the sharp edges.

Apply only one layer and minimize tape overlap as much as possible to avoid increasing the outside diameter of the shaft. Lubricate the taped shaft with oil or grease, then slide the seal onto the shaft and into place.

 

Temporary Fixes

Sep 18, 2013

 A professional mechanic takes pride in fixing things "right." But there are times when there isn't time or proper parts available to make emergency repairs. So you do what has to be done. I'm not bragging about these "fixes"....I'm confessing.

-The threads on the drain plug hole in a "pot metal" gear case stripped out. The cost of the entire gear case was frightening; there were enough threads left to screw in the drain plug, but not enough to keep it from leaking. With the customer's permission I used contact cleaner to clean the threads, smeared quick-drying JB Weld on the remaining threads and on the threads of the drain plug, and screwed in the plug till it was snug. We did other repairs for a half hour, then poured in oil, crossed our fingers, and...no leaks. To my knowledge, that drain plug is still in that gear case. I apologize to whoever bought that machine when the customer finally traded it off.

-While making other repairs to a combine, I noticed a hole worn in the bottom of the clean clean grain elevator housing. With the customer's encouragement, I layered duct tape over the hole and wished him good luck. He finished the final 500 acres, and the patch was still in place when he brought the combine to the dealership for winter repairs.

-A bearing went out on the hexagonal drill shaft on the wing section of a 12-row planter, stripping the hexes off the shaft where the bearing sat. With a thunderstorm on the horizon, we pulled the shaft, installed a new bearing, reversed the shaft so the bearings sat in slightly different places, and finished the field. That was five years ago, and every spring the farmer reminds me that he still hasn't spent the money to get a new shaft.

Rats. I apologize. This blog isn't working out like I hoped. Over the years I've performed dozens of temporary miracles with duct tape, welders, zip ties, fence posts, pieces of inner tube and other "accessories" in my efforts to keep customers' machines running. I thought I could regale and entertain you with examples of my creativity. But aside from the few repairs I've mentioned, the rest have faded into a hazy corner of my memory that's cluttered with, "This might work...", "We can try this..." or the classic, "What have we got to lose..."

I've done some pretty spectacular cobble-jobs over the years. Unfortunately--or fortunately--my mechanic's mind has blocked out most of them. Customers will come in and say, "Remember when you welded this or that, or duct taped that whatchamacallit..." and I honesty can't say that I remember doing it. My mind protectively deletes things I've done that have potential for embarassment or OSHA fines and penalties.

So you'll have to take my word that when you're desperate and customers are pleading, you can do amazing things with duct tape, zip ties and/or a welder cranked up to 300 amps.

The Cheesy, Cheap Way To Fix High-Tech Problems

Sep 15, 2013

 Farmers are heading to the field this fall with even more complicated technology in their tractor and combine cabs. There will be problems with that high-tech gadgetry. There will be expensive service calls and repairs. But before wasting money or profanity at a frozen screen or a warning code that won't go away, always try a couple simple, free steps that sometimes cure high-tech problems.

If a screen freezes or a warning code comes up and refuses to go away no matter how many times  you hit the "Clear" button or smack the console with the palm of your hand:

-write down all the letters and numbers of all warning codes on the screen for future reference. Your owner's manual may have a listing of what the code means and how to fix the problem. If you call your dealership or the system's manufacturer, they will ask for that information.

-write down calibration values related to yield monitors, acre counters or other inputs that you have to calculate, calibrate or input, because they are unique to your machine and its configuration. Some of the following steps may wipe out that info, and you'll be glad you saved it. In fact, it's a good idea to write all that stuff down whether or not you're having problems. It's better to write that stuff down while things are going good than to discover when problems arise that you've lost all that input data you worked so hard to develop.

-with all the relevant info saved, shut off the machine. Wait a full minute before restarting it---it may take 30 seconds or more after key-off for the various computerized systems to save data and actually shut down. Restart the machine and see if things behave better after they reboot and reconfigure.

-if a key-off, key-on sequence doesn't fix the problem, turn off the ignition switch, and unplug the display, console or in-cab device that's causing the problem. Wait for a minute, then plug it back in and re-power the system. 

-if the system still refuses to behave and perform, consider doing a cold boot--ie, kill ALL power to the system. This may be as simple as disconnecting the power wire to an aftermarket cab display, or as drastic as disconnecting the machine's main battery cable. There are many forms of "cold booting" a malfunctioning system, but the idea is to remove all electrical power so even the feeble constant-power circuits in the system are forced to re-boot and re-configure when you reconnect the power source.

If none of those steps fix the problem, it's time to call the tech support phone number in the owner's manual or at the local dealership. They may know arcane, hidden things to do that will fix the problem over the phone. If not, it's time to schedule a service call that will turn your headache into a headache for your local technician.

"I need more power, Scotty...!"

Sep 09, 2013

 Sometimes engineers and mechanics feel like the beleagered Scotty on the old TV show "Star Trek." No matter how well we get the machines running, somebody is always calling and telling us they, "need more power!"

Sometimes we can tweak something or find a malfunctioning component to give customers more power. But in many cases, when we check out the circumstances, the customer may be partly responsible for the perception of inadequate power.

Let's use a 400-horsepower combine as an example. In your mind, right now, make an estimate of how many horsepower it takes to thresh, separate, clean, and elevate grain into the grain tank. Hold onto that horsepower estimate for a minute.

Engineers have told me that an 8-row cornhead in 200-bushel corn at 20 percent moisture can pull as much as 125 horsepower. More, if it's a chopping head. They also tell me that the straw chopper on an 8-row combine in "average" corn can pull more than 100 horsepower. 

Most combines have some sort of aftermarket grain tank extension. You can check my math, but when you fill an extended grain tank till grain is stacked high enought to impress the neighbors and threaten low-flying aircraft---you're adding weight to the combine equivalent to setting a 200-hp front-wheel assist tractor with duals in that grain tank. So, can we figure an extra 50 horsepower is required to power a combine more than half full of grain through the field...?

Then we'll pull an extra 25-hp when we engage the unloading auger, and at night when we've got all those lights turned on the 200-amp alternator pulls a few extra horse, and the air conditioner takes a few horse, and if we've got a corn reel or other extra hydraulic motor running on the combine it's going to pull a few horse. All of a sudden we've used up close to 300 out of the available 400 horsepower. Leaving 100 horsepower to do the actual threshing, separating and elevating of the grain.

How does that 100 available horsepower compare to your estimate of how many horsepower it takes to operate the combine's separator when it's hogging through high moisture corn or green stem soybeans?

My point is, no matter how many horsepower engineers put into combines, and no matter how many horsepower mechanics are able to squeeze out of the those machines, there are never enough for the way we use them. So the next time your combine lugs down and slow-shaft speed warnings start buzzing as engine rpms fall below optimum levels, pull back on the hydro lever, and let the poor machine catch its breath. And then think about how fast you're pushing the corn head, how tough and green are the stalks the straw chopper is gnawing on, and how high is the extension you added to the grain tank.

If your combine was a starship, there would be a frustrated First Engineer like Scotty down in the engine room shouting, "But Captain, I'm giving her all she's got!"

 

Wiring Lice

Sep 06, 2013

 Our dealership requires mechanics to wear gloves as much as possible when working on equipment to minimize scrapes, cuts and abrasions. A couple years ago, shortly after the mandatory glove policy was instituted, I was sent to the field to repair a customer's combine. As I stepped out of my service truck I pulled out a new pair of the safety-yellow, rubberized gloves and slipped them on as I surveyed the ailing machine. 

I saw the customer eyeing the gaudy gloves. I'd known him for years, we often joked back and forth, and I couldn't resist the opportunity.

"Fresh, sanitized gloves for every machine," I said. "We've got a couple combines over on the west side of the county that have wiring lice, and we're trying to keep them from spreading."

"Wiring lice?" he said.

"Yeah, they're teeny little varmints that get into those big electrical wiring harnesses and eat the insulation off the wires," I said as I grabbed a couple wrenches and walked toward his machine. "Causes all sorts of problems.They don't fly, they don't jump, they just crawl or get transferred by contact, so we got these special gloves to keep from transferring them between machines." I stopped and scratched vigorously around my collar. "They don't bite humans, but it sure itches when they crawl around."

"Wiring lice," he said, as he took a step away from me.

I never said anything more about the potential plague. I made a point of scratching every time I walked past him, and by the end of the service call, he was nervously itching his forearms. 

I'm pretty sure he knew I was joking. The topic of wiring lice has never come up in subsequent conversations. But I'll bet he was scratching for the rest of the day till he convinced himself I wasn't serious.

 

 

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