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A Kubota ZL1500.

Here is an article that attempts to clear some confusion surrounding ZEN-NOH tractors. Anyone familiar with direct import Japanese Domestic Market (JDM) Kubota tractors is familiar with the name ZEN-NOH, or sometimes written as Zennoh or Zen-Noh. Exact semantics aside, many have seen the name adorn the side panels and hoods of what look like normal Kubota tractors. Before we get into a lesson on ZEN-NOH, I’ll tell you what ZEN-NOH is not – it is not a tractor brand name!

What is ZEN-NOH?
ZEN-NOH is an agricultural cooperative in Japan founded in 1948. It is a government owned and controlled organization that through their strength in numbers is able to buy large quantities of agricultural supply at a discount. There are many cooperatives that operate in Japan, but ZEN-NOH is the largest in Japan’s National Federation of Agricultural Cooperative Associations. Actually, not just Japan, but the entire world. The largest agricultural cooperative anywhere, is ZEN-NOH.

ZEN-NOH is a means for millions of Japanese of farmers to grow and market their products and have access to basic supplies for running a farm. This is evident from the name of the co-op – the translation of ZEN-NOH is “all farmers”. The size of the cooperative means that vast supply quantities are available at lower pricing due to massive purchasing volume. ZEN-NOH makes sure fertilizers are available, oil, fuel, parts, equipment and so the individual farmer does not have to concern themselves with sourcing these.

An organizational chart for the ZEN-NOH agricultural cooperative.

How big is this Cooperative?
Pretty big. 2006 numbers peg annual turnover at about $56 billion USD. The cooperative has about 4.5 million farmer members and employees about 12,500 in the organization overhead.

They consistently maintain the number 1 spot in the Global 300 – a ranking of the world’s largest cooperative organizations. Everything from agricultural coops, retail, wholesale, insurance, electric power, banking and credit union cooperatives are listed in this index.

Interestingly, Japanese insurance cooperative Zenkyoren occupies the number 2 spot on the index which is actually ZEN-NOH’s insurance division. Combined, ZEN-NOH and their insurance division, generate a little more than $100 billion USD in revenue every year.

ZEN-NOH and its insurance division, Zenkyoren, occupy the number 1 and 2 spots in the top 25 cooperatives in the world.

Where does Kubota Fit In?
Well, when you are the number 1 agricultural cooperative in the world, Kubota will make tractors just for you and stick your name on them.

Since ZEN-NOH is the largest agricultural coop in Japan, it has tractors, rice combines, wrapping machines and many other products – not just equipment, produced for them under their ZEN-NOH brand name by some of the largest companies in Japan – Kubota included. It is not unlike your local grocer having its own brand of cereal, salad dressings or pasta sauce – it had another company manufacture those items to its specifications.

Kubota has manufactured literally thousands of tractors for ZEN-NOH over the years and labeled them right on the assembly line with the ZEN-NOH name plate. Often a Z prefix was added to the existing Kubota model number identifier making an L1501 into a ZL1501 tractor. Once built, the tractor was mated to a matching Kubota tiller and shipped directly to The Procurement Division of ZEN-NOH for their disposition.

A Kubota ZL1801 manufactured for the ZEN-NOH agricultural cooperative.

Established in 1890, Kubota has had a long history of producing farming machinery in Japan. Kubota sailed across the Pacific in 1969 and found a ready market in the US for its new product line that included never before seen compact tractors. Needless to say, the 21HP L200 was an overnight sensation and Kubota Japan got busy incorporating in the US in order to meet the demand for their hot little orange tractors. Domestically in 1974, Kubota followed up the success of the L200 with the B6000DT – at 12HP it was the first compact 4 wheel drive tractor ever made.

How did I end up with a ZEN-NOH Tractor?
At this point you might be wondering – “very interesting, but how did my ZEN-NOH tractor get from the cooperative all the way across the ocean to my shed in Tecumseh Kansas?”. Yes, this is an important piece of the puzzle. We have called this first article ZEN-NOH and Kubota: A Partnership because that is how these two organizations started out – one producing equipment for the other. In ZEN-NOH and Kubota Part 2, we start to see how these tractors started to make their way across the ocean…

Service Department Vic

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ZEN-NOH and Kubota Part 2: Importation
ZEN-NOH and Kubota Part 3: Lawsuits
ZEN-NOH and Kubota Part 4: Loopholes
ZEN-NOH and Kubota Part 5: Fallout
Discovered it’s a Gray Market Kubota? Relax.
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Forum: Gray Market & Zennoh

Hello, Mr. K here with a quick update.

After some testing, we’ve launched our new OrangeTractorTalks forums! We want to open the door a bit and let our faithful viewers “meet up” and learn not just from us, but from each other as well. You can find the forums at this link:

http://www.orangetractortalks.com/forums

or by selecting Forums in the navigation quick links in our banner above.

Registering on the Forums
A side-effect of moving toward a more robust forum system is that we cannot reuse the existing user accounts our viewers have been using within the article-side of the site. All that is required to gain access to the forums is re-registering your information with the new system (which is fast and easy). The re-registration link is:

http://www.orangetractortalks.com/forums/register.php

Reuse my old User Name?
Yes, when you re-register you can still reuse your previous user name, password and email if you like. If you we not in love with your user name, now might be a good chance to change it.

What about posting Comments on Articles?
Posting comments on articles will depend if you have an original article-account already in place (ie. an account with us before the forum arrived). If you do, yes, you can still post comments on articles, but for now, you will have to sign in to the article-side of the site separately. Not ideal, but it works for now.

Posting comments on articles if you are a new member (an account with us after you are reading this message), then you will not yet have an article-side account created and will not be able to post comments that are linked to your account – you can still post comments by filling in your information manually on the comment box. We’re working on this, but you will have access to the forums to view and post.

View the forums from time to time and help out your fellow man – who knows, you might learn a thing or two!

Mr. K

In this post we are going to take a look at a very common service complaint that affects a wide variety of early Kubota B and L series tractors – steering box failure! In a follow up article, we will examine how to undertake a steering box repair and overhaul.

Symptoms of Steering Box Failure
The number one symptom of a failed steering box is that the steering will feel real loose and the front wheels of the tractor may wobble and oscillate. This is because the internals of the steering box are no longer integral and tight. Symptoms of steering box failure include:

• wobbly steering
• mushy, loose or unresponsive steering
• raising the front of the tractor with a jack – grinding or resistance when turning wheels from lock-to-lock
• shaking the steering wheel – feels really loose and ready to come right out of the tractor

If your Kubota B or L series tractor exhibits this type of wonky steering, do not ignore this repair! It is foolish and unsafe to operate your Kubota this way.

What Causes this Failure?
Typically, steering box failure is caused by 3 conditions, all working together to break your Kubota:

1. Upper Steering Column Bushing Wears Out
   The failure of the steering box is most likely due to water making its way into the steering box through a defective, missing or worn bushing at the top of the steering column.

   This thick rubber bushing holds the steering shaft centered in the steering tube. When new, this bushing fits very tightly against both the steering shaft and the inside of the column tube. After several years of steering and turning your Kubota tractor, this bushing wears out and is no longer tightly holds the steering shaft.



View of the top of the steering column - it is here that we should find a bushing (not shown).



A view of two upper steering column bushings. Notice the worn out one one the left has lost its shape and is a bit oblong - a result of turning and steering a Kubota over many years.

2. Rainwater
   Tractor is stored outside in the elements allowing rainwater to trickle down steering shaft. A few drips at a time, this rainwater will run down the steering shaft and toward the steering box.
3. A Plugged Weep Hole
   Kubota did engineer a back-up fail safe into the steering box and column to prevent catastrophic failure and keep water our of it – a weep hole. Unfortunately, very few owners know of this back up weep hole system and as such do not service it.

   At the very bottom of the steering column, where the metal tube mates to the cast iron housing of the steering box, there is a small weep hole facing downwards. If you look closely at this picture you can see that the weep hole appears solid and plugged.

   

   At the bottom of the steering column is a weep hole that serves to let accumulated water out of the shaft. They typically get plugged with dirt and crud as shown here.

   The next step in the chain of events that leads to a broken steering box is that over a period of time, rainwater, dirt and debris make their way down the steering shaft and eventually plug the weep hole.

Weep Hole? A Big Deal?
You bet! The weep hole is located just above the lower steering column seal and bearing. This seal is a typical rubber friction seal that is spring tensioned. When the weep hole plugs, the entire steering column can fill with a head of water, dirt and junk. Since this moisture can no longer egress the column, the water will begin to move past the seal, right into the steering box – this is bad.

Since oil floats on water, the lower bearing that supports the steering shaft begins to go unlubricated causing severe wear. Once infiltrated with moisture and water, the bearings fail falling apart causing the steering shaft to wobble.

A shot of failed bearings freely rolling around the inside of the steering box - the source of wobbly unresponsive steering.

If the excessive wear on the steering shaft was not enough to destroy the steering box, then the first time the temperature goes below zero, the water in steering box freezes, causing expansion that fractures the box case – either out the bottom or it cracks the case on the sector shaft side.

A cracked steering box caused by rainwater getting into the box and then freezing, exploding the housing.

Entirely Avoidable
It’s unfortunate when steering box failure occurs like this since that little hole can be easily cleaned out with a small drill bit rotated by hand.

I am also of the opinion that steering box failure is somewhat of a service secret at Kubota. You will not find a shred of info in any Kubota service literature, technical service bulletin or technical training manual that discusses  keeping that drain hole clear, yet Kubota sells replacement steering box shafts and bearings by the truckload!

Some tips to prevent this type of failure from occuring with your Kubota:

• locate your Kubota’s steering system weep hole and get in the habit of clearing out the dirt and debris – a simple drill bit rotated by hand is enough
• avoid parking your Kubota out in the rain which allows water to travel down the steering shaft toward the box
• inspect and replace the upper steering column bushing if its worn out or oblong

Servicing the steering column weep hole is simple as rotating a drill bit by hand. We want to keep this area clean and free to let excess water pass.

Too Late. I’ve got a ruined Steering Box.
Okay, not to worry. If it looks like the steering box on your Kubota tractor requires an overhaul, or the box itself has a pressure crack due to freezing – stay tuned. In the next installment we will take a look at how to undertake a steering box repair job!

Service Department Vic

Related Articles
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Forum: Service, Repair & Maintenance

Hello again, Mr. K here,

Just a quick update on some of the things we are working on behind the scenes here at OrangeTractorTalks. One of them is a new discussion forum built using a professional grade forum system. Up until now, the communication has been a bit one way – myself or Service Department Vic post some articles and try to handle the comments best we can. We know there are lots of other experts out there too that could share their advice and help the community, so, a forum is the next logical step.

A sneek peak at the forums on their way to OrangeTractorTalks

On the new forum you will be able to post your own custom avatar, signatures, tractor pictures, message other users privately, post new threads and reply to others to help them along. Post and help out enough, and you’ll advance through the ranks and gain the admiration and respect of everyone (on the forum that is).

Look for our forum roll out within the next couple of weeks – we’ll send you an email at that time with instructions on how to sign up on the new system.

Mr. K

Here is a subject that is sure to ignite discussion amongst many Kubota tractor owners. If you shed park your Kubota in sub zero temperatures you might be tempted to use some other kind of starting fluid to get your Kubota tractor firing. Every now and then we hear the question, “Is it OK to use starting fluid on my Kubota tractor?” The simple answer is no!

A Kubota L185's 2 cylinder diesel engine with a huge hole in the block.

What is Starting Fluid?
Starting fluids are comprised of volatile hydrocarbons, heptane, butane, hexane and a mixture of up to 60% diethyl ether. Ether is clear, colorless liquid that has a low autoignition temperature – handy when the engine you are attempting to use it on it cold. The temperature at which ether auto ignites is 360 Fahrenheit or 182 Celsius. Ether also has a high cetane number, a measure of fuel ignition delay – ether has a high index and so the delay from fuel injection to fuel combustion is shorter. Finally, ether has no lubricating properties like normal diesel fuel does, making it harder on gaskets and seals. Starting fluid is widely available at any automotive supply chain and typically costs $4-5 per spray-can sized can.

How a Diesel Engine Fires
When we take a closer look at the basic mechanical principles of a diesel engine it become easier to understand why reaching for the starter fluid when you are having a tough time getting your Kubota to start is not a good idea.

In any diesel engine, only air is introduced to the combustion chamber. The compressing of this air raises the cylinder temperature to over 1000 degrees F (550 Celsius). At this precise moment, the tip of the injector opens and diesel fuel, also under pressure, is injected into the top of the combustion chamber. The extreme heat then ignites the atomized diesel fuel, firing the piston downward supplying power to the crankshaft.

Your Kubota’s diesel engine produces between 412 and 470 psi of compression. The air sucked into the engine on the upstroke is squeezed at a 19:1 ratio. Depending on the engine model, the tips of the injectors will open between 1700-3400 psi. These are high compression numbers! Your Kubota’s engine is pressure ignited and built to operate within its design limitations of 470 psi of compression. When we introduce an unregulated fuel source, like starting fluid, into the combustion chamber, the compression is much more volatile and can exceed specification – in short, that fluid can grenade the engine.

The Effects of Starting Fluid
The only way to get starter fluid into the engine of your fuel injected Kubota tractor is through the air box. When you spray starting fluid into the air box of the engine, it replaces a certain volume of air with a highly explosive and volatile fuel.

Once the engine is cranked over it quickly begins to compress the air and starting fluid now inside the combustion chamber. As the piston begins to move upwards compression increases and cylinder temperature begins to climb. However, since starting fluid will ignite at a lower temperature 360 F (182 C) versus the diesel fuel at 1000 F (550 C) a flame inside the combustion chamber occurs ahead of the injectors opening to deliver their fuel.

Kubota fuel injection pumps are designed to begin delivery to the injector at 14-22 degrees Before Top Dead Center (BTDC), depending on the specific engine model. This means that as the piston in still traveling upwards, a flame has already started inside the combustion chamber! Spray some diesel fuel into this flame ball and add a little more compression and you can see where this is going. BANG!

With starting fluid displacing the air, ignition now occurs explosively, uncontrollably and with such force that the upper limits of compression pressure are well exceeded. Never, ever use starting fluid on a diesel engine with glow plugs! KA-BLOOMIE!! Kubota tractors all have glow plugs!

Kubota Technical Service Bulletin SB78-38
In 1978 Kubota issued a service bulletin covering the use of ether or starting aids in their engines.

Kubota's TSB SB78-38 was the 38th bulletin issued in 1978. The use of ether or starting fluids resulting in damage to your equipment would not be covered under warranty.

10 Quick Cold Weather Starting Tips

1. Have a good strong battery with 850-1000CCA (cold cranking amps).
2. Use a magnetic block heater if your Kubota does not have a water jacket heater to keep the engine block, oil pan and oil warm.
3. Crank over the engine for 15-30 seconds with the cylinder head decompression knob pulled out to circulate warm engine oil to the upper parts of the engine.
4. Glow the glow plugs for the appropriate time as dictated by the outside ambient temperature. Below zero give them 60 seconds of preheat. Over-glowing does not hurt.
5. Service your tractor regularly, change filters and fluids.
6. If the engines begins to fire and is running a little lumpy, quickly turn the key backwards to reactivate the glow plugs and bring the temperature of the combustion temperature back up.
7. Set a trouble light on top of the engine for an hour or so to warm up a frozen engine. Place it by the air plenum and injector lines but do not leave it unattended or overnight.
8. Remove the battery and bring it inside the house if necessary. A warm battery will crank your Kubota over like a hot day in July!
9. Park in a heated garage if possible, if not, even an unheated shed offers a degree of protection.
10. Make sure the fuel in the tank is fresh, number 2 diesel. If you store your own fuel, make sure it has been treated with an extender and it does not hurt to use a little cetane booster.

Service Department Vic

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Cold Weather Starting Tips
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How to Clear Snow with a Snow Blade

Hello, Mr. K here with a quick tip that lets you watch your favorite Kubota YouTube videos in high definition. This is particularily handy if you want to see the finer details that we point out in our videos that harder to see with lower quality video.

How to Enable High Quality Playback
Simply start playing the video and then move your mouse to the bottom right corner. A menu will roll up that lets you select “HQ” for high quality playback. The video will take a moment to stream in the higher quality content and will resume playing from the position where you toggled the quality.

The HQ button in the menu that rolls up from the bottom right toggles quality between low and high. When the button is red you are on the high quality setting.

Results
Here is a frame from our video on how to clear snow with a snow blade, and you can see the difference toggling the quality setting makes. YouTube in the future might have high quality set to on by default, but for now, you have to select it manually.

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