August 2010 Archive for In the Shop

 Let's see a show of hands--how many of you have had to change fuel filters on harvest equipment, then sat in the combine, tractor or truck cab reeking of diesel fumes for the rest of the day? Uh-huh---most of you, including me. 

Modern diesel engines are getting more and more finicky about fuel cleanliness, so now is the time to avoid in-field baths of diesel fuel. Spend a little time changing fuel filters on BOTH equipment and especially storage AND fuel transfer equipment to keep those finicky engines happy.

Diesel fuel is delivered to your farm filtered to 10 microns. Many new diesel engines require fuel filtered to 2 microns. Engine manufacturers recognize the discrepancy and that's why you often see two, large fuel filters on newer engines--a pre-filter and a final filter. Good, "10 micron" fuel delivered to your farm is no problem for those filter systems.

The problem is if fuel GAINS contamination while stored on your farm, during transport to the field, or during transfer to the machine. When on farms I often glance at their fuel storage tanks, and often note the "sediment glass" on the bottom of the pump's filter is half-full or more of slimy gunk or watery fuel. That hints there is a lot of contamination in the tank itself.

I've found that local fuel delivery jobbers are really anxious to help farmers clean up tanks. They have special chemicals to flush infamous "black slime bacteria" from diesel tanks. Their advice on how to clean up fuel storage and handling systems pre-season can help prevent in-field fuel filter changes. 

 In my "In The Shop" column in the September issue of Farm Journal Magazine I look at how improved crop genetics have challenged modern combines during harvest. Here are a few of the major points:

-Bt corn genetics have made cornstalks like small trees. Running corn head deck plates at recommended spacing may encourage corn heads to cut off the upper portions of the stalks and feed them into the combine. The extra stalks, leaves and debris can overload straw walkers or the separating portions of rotors and cause grain to "go out the back." Don't blame the combine for throwing grain out the back if the cornhead is feeding too much junk into the front of the machine.

-Bean and small grain stems have gotten tougher due to improved genetics. Sickles AND the guards they work against must be sharp. Make certain the lower edges of rock guards are "sharp" and not rounded. New sickle sections are wasted if they have to work against rounded guard edges.

-When deciding whether to replace straw chopper knives, forget the current price of knives and consider how much trouble you had last spring getting straw and residue through your field cultivator or planter row cleaners. Tougher stems and stalks wear chopper knives more quickly and result in poorer shredding action. Plus, dull chopper knives pull harder and are a drain on engine horsepower.

This harvest, take a holistic approach to adjusting combines. Don't overlook the way headers are feeding material into the combine. And accept that there are conditions--wet straw, rubbery cobs, brittle stalks, rotted tips of ears---where it may NOT be possible to get a combine set perfectly. Any mechanic that says he can set a combine to combine any crop under any condition to do a perfect job every time...well, it ain't me. I'm only human.

 Electrical tech books and electronics classes tell mechanics and do-it-yourselfers (DIY) not to pierce or disrupt the insulation on electrical wiring while testing circuits. But sometimes there's no other way to accurately test circuits.

The tool industry has noted the problem of testing circuits and offers several useful tools to probe wiring. Back-probes are gadgets with thin, stiff wires that allow the user to probe into the backsides of electrical connectors to make contact and test individual wires. Back-probes come in a variety of sizes. A few come with the probing wire at a right angle to its "handle", which is handy when probing big connectors with lots of wires.

My favorite probing tool is "The Claw" by Ferrett. Hard to describe, but it's a thumb-screw gizmo that cradles the wire to be tested so a pin-point probe can be screwed through the insulation of individual wires. I like The Claw because I can test wires away from crowded plugs and leave individual Claws connected to the wire for repeated tests. The Claws come four to a package and are color-coded red, black, yellow and blue to help keep track of which probes are testing which wires. The Claw sells for between $30 and $40, depending on where you buy the kit.

There are other ways to probe and test wires, including the often painful process of simply poking the tip of a voltmeter probe through the insulation (and often into your fingertip). That works, but isn't very tidy. Whatever type of probe is used, be sure to close the small break in the insulation to prevent corrosion to the wires. I like a dab of "Liquid Insulation" a liquid plastic that seals to a rubbery finish. A couple turns of electrical tape is better than nothing.

Above all else, don't use a pocketknife to peel back an inch of insulation. Unless you want to spend a lot of time re-testing the same wire next year, after a bunch of greenish corrosion disrupts voltage and resistance in that wire.

 Engineers are devious souls. When mechanics refer to tech manuals to disassemble or re-assemble machinery, we often are told to use a "JDG2530 tool" to remove a seal, install a bearing or align a shaft.

With luck, the dealership has the JDG2530 tool in the tool room. I can guarantee if a tech manual calls for a JDG2530 tool, the job will be much, MUCH easier if that tool is available. I've managed to devise, improvise or invent tools when the specified tools wasn't available, but promise that it's always easier with the proper tool.

I'm not adverse to ordering and buying special tools from the manufacturer. That way, if I'm on a service call, the shop doesn't have the tool or another mechanic is using it, I've got the secret weapon to make the repairs go more easily. In the same vein, if you're a farmer who does a lot of his own repairs, and often makes the same repairs, it might save money and time to invest in factory-recommended tools.

Most dealerships have catalogs of factory-recommended tools. A polite farmer might get a chance to peruse that catalog and order special tools that would make home repairs much easier. If you're not sure what tools you need, ask a mechanic--they can tell you which tools save time and aggravation.

Special tools aren't cheap. I just spent $88 on a torque adapter wrench that is no more than a flat chunk of steel 6 inches long and 1 inch thick, with a 12-point, 30 mm wrench in one end and a 3/4-inch square hole in the other end. But there are times when that pricey little chunk of metal saves me an entire hour on certain repairs, so it will easily pay for itself.

By the way, many factory-recommended tools are manufactured by OTC Tools. You can't order factory tools direct from OTC, but the OTC website (Google search: "OTC tools") has a lot of nifty specialty tools that are darned close to many of the factory-recommended tools we have at dealerships. Not all of them, but enough to make it a fun internet shopping trip.

 

 I've done it, other mechanics have done it, and every summer at least one customer does it: wrap a 'coon, 'possum, cat or other critter around the innards of a combine. 

For various reasons combines are popular spots for wildlife and small domestic animals to rest or nest. Maybe it's because combines have lots of crop debris that makes good nesting material. Maybe it's because they're parked in the back corners of machine sheds where nobody bothers them for months at a time. Maybe it's because farm dogs and other larger predators can't easily get inside combines. Whatever the reason, critters like to set up housekeeping deep inside those big machines.

And then a farmer or mechanic decides it's time to get the combine out and prep it for harvest. We start up the engine and ease it out of storage. Most of the time animals hiding inside the combine bolt for safety at the sound and vibrations of somebody climbing the ladder to the cab. But there's always one animal--or a nest of young animals--that "freezes" in fear and stays hidden deep within the machine.

So, when the mechanic or farmer engages the separator...much ugliness occurs. Last week a co-worker spent the better part of a day untangling a big raccoon from the horizontal unloading auger on a combine. Last year another co-worker spent two days removing a 'coon from the engine fan shroud of a combine and then replacing the shroud, fan blades, etc. etc. that were damaged.

I've learned to be very cautious when bringing combines out of storage. If possible I make lots of noise when approaching the machine. I'll bang on the sides of the separator if there are animal tracks in the dust on the machine. I start it and ease it out of doors without engaging the separator. If possible, I'll shut if off and let it sit for a half hour or more. When I finally have to engage the separator, I try to gently "bump" the separator into motion once or twice--just enough to make everything move, but not enough to actually rotate and trap any critters lurking within. After two or three "bumps" to give any animals time to escape, I grit my teeth, engage the separator and hit "full throttle." If there's anything still inside, I want it ripped, torn, shredded and expelled, rather than wrapped and clogged.

This isn't the most pleasant topic to discuss, but...discussing it is better than cleaning up the results of blithely running a combine fresh out of storage.

 

Small mechanical tidbits that you probably already know:

-tighten a lock collar onto a bearing in the direction the shaft will rotate. 

-the closed end of the retaining clip on master links on roller chains should be toward the direction the chain will travel. The split end of the clip should "trail" when the chain is in motion.

-any half-links in roller chains should have their narrow end "leading" when the chain is in motion. The wide end of half-links should "trail".

-the idler or tensioner pulley or sprocket on any belt or chain should contact the "slack" run of the belt or chain. The powered run of a belt or chain should always be straight and direct from the powered pulley/sprocket to the driven pulley/sprocket.

-when shutting off an acetylene torch at the cutting handle, close the acetylene knob first, the oxygen knob last. That way oxygen clears any remaining acetylene from the mixing chamber and tip, reducing the chance of a flame burning back into the tip or handle.

Like I said, you probably already knew this stuff, but...you'd be surprised how often equipment comes to the shop with lock collars loose because they were tightened the wrong direction, master links missing clips because they were installed backwards, and belts or chains goofed up because somebody put the idler on their "driven" run. 

And, yes, I've done all those things myself because I didn't know better at the time. Some would say I still don't know better...
 

 I'm working on a story for an upcoming issue of Farm Journal that deals with cleaning up and selling scrap metal piles that inevitably grow behind farm shops. One scrap metal processor I interviewed for the story mentioned the challenge of getting rid of old fuel barrels, empty oil barrels, pesticide barrels and other environmentally unfriendly containers. The same goes for worn out, rubber-clad wiring harnesses, planter guage and press wheels, and old tires still mounted to their wheels.

The politically correct solution is to haul contaminated containers or environmentally hazardous wastes to EPA-approved disposal agencies or collection sites. But most of those sites are associated with larger urban areas and relatively unavailable or inconvenient to farmers or ranchers. 

What is a farmer or rancher who wants to be environmentally responsible supposed to do with his hazardous, contaminated wastes? I have a feeling a lot of worn-out rubber tires get burned after dark, when the thick, oily smoke won't be noticed. The same goes for plastic pesticide bags or  jugs. I've been leery of that disposal process since my uncle spent time in intensive care simply from breathing the smoke from burning insecticide bags. Old fuel barrels and oil drums...? I've heard of guys who flush them with water then use a torch to cut them into manageable pieces, but I'm not volunteering for THAT job. 

The majority of farmers care about the environment and avoid doing anything that could harm the precious farmland they hope to pass on to their kids and grandkids. But sometimes we have to deal with situations that challenge our ethics and make us hope we're doing no long-lasting harm.