OrangeTractorTalks

We have examined the effects of starting fluid on your Kubota and these two pictures serve as a reminder against using ether or starting aids.

These pictures show the block of a Mitsubishi/Satoh Beaver 370D diesel engine in which ether was used in an attempt to get the equipment firing. Although this is not a Kubota piston that is smashed into pieces it could very well have been – both Satoh and Kubota engines are high compression. Premature and violent detonation caused by ether burning ahead of the injectors opening to deliver fuel, puts serious strain on the piston and connecting rods.

Skip the ether and reach for your mouse and click on one of our articles to give you tips on getting that Kubota to start!

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Wondering how much that clutch job might be for your L series Kubota?

OrangeTractorTalks reader Brian recently requested a quote for what we call a clutch overhaul kit for his L2350. This estimate is for a single disc dry clutch, and although for the L2350, other similar models like L2050, L2250, L2550, L2650 or L3250 would have similar pricing for these clutch components. If you are thinking of tackling this job as a DIY’er, plan on setting aside 8-10 hours – a good long weekend job.

Kubota L2350 Clutch Repair Pricing

*prices in USD

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Forum: Service, Repair & Maintenance

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

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Forum: Service, Repair & Maintenance

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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Ok, you are convinced you want to ballast your tires, chosen a type of ballast and now, need to get your water, CaCl2, antifreeze or beet juice mixture into drive tires in the appropriate quantities.

Liquid Ballasting Guide

1. How Much Ballast
   Firestone AG has a handy table that relates tire size to gallons of water, or gallons of water and pounds of calcium chloride, and how much ballast weight would be achieved, per tire. If you are going for a 50/50 antifreeze ballast, then simply use 50% of the amounts listed for water-only and fill the remainder with antifreeze.
   
   You can lookup how much ballast you need here. Note that the list of tires is spread over several pages in the chart – scroll all the way to the bottom and look on the right to flip between pages. Tires smaller than 8.3-20 will be listed in pages further back in the tables.
   
   For example, using the Firestone’s table, we see that 11.2-24 R1 AG tires, a common Kubota size for a rear tire, would each require 24 gallons of water yielding 200lbs of ballast weight. If we were using a CaCl2 solution, mix 19 gallons of water with 95 lbs CaCl2 yielding 253lbs of ballast weight. Depending on your ballast type, that puts another 400-500lbs of weight on the ground to help maximize traction!

2. Water or Mixed Ballast?
   If you intend to operate your Kubota in the winter or where outside temperatures drop below freezing, you will need to have the tires filled at a tire shop that has the pumping equipment necessary to install a mixed solution. You can still use the chart above to determine how much mix you will need and arrange that in advance to save yourself some money. I’m not aware of any do-it-yourself pumping methods that would safely achieve the results needed, so this job is best left to the professionals. The rest of this guide assumes a water ballast is used.

   

   Attemping to fill a tire using a do-it-yourself pumping system, as shown here, does not work. Either obtain the proper equipment or head over to your tire shop.

3. Gather Tools
   For tools, you will need:

   • a garden hose
   • water fill attachment
   • a tire fill adapter
   • a floor jack
   

   Water filler will be attached to the garden hose and the tire fill adapter.

   

   A close up of what a tire fill adapter - available from any auto supply store.

4. Let Air Out of Tire
   Using the floor jack, raise the wheel. Remove the valve stem core from the tire and let all the air out, save for maybe 5-7 psi – just enough to keep the tire bead seated in the rim. Rotate the tire so the valve stem is in the 12 o’clock position.

5. Start Filling
   Thread on the water fill attachment, attach the tire filler adapter and then turn on the garden hose. You may need to occasionally turn the water off and burp the tire. As the water enters the tire it will begin to displace the air resulting in some compression. Loosen off the hose fitting and let the trapped air escape. Once all the air is exhausted, resume filling.
   
   You will want to fill the tire no more than 75% full with water. The 75% full mark is achieved when the water in the tire has reached the level of the valve stem as the tire is filled in the 12 o’clock position. It is a good idea to just slightly overfill the tire with water, and then holding the tire and wheel perfectly upright, remove the water filler adapter. The excess water will purge itself down to the level of the valve stem all by itself and also ensures that the same amount of water are inside each
   tire.

6. Pressurize Tire
   Once water has stopped coming out of the valve stem, replace the valve core. Lower the floor jack and with the full weight of the tractor on the tire, fill the tire to the correct air pressure as indicated on the sidewall of the tire, or in your Kubota Operator’s Manual.

7. Ballast Removal
   Water ballast is removed from the tires by rotating the valve stems down to the 6 o’clock position and removing the valve cores. The head of air pressure will force the water out of the tire. If the water is coming out a little slow after a while, simply rotate the valve stem back up to the 12 o’clock position, fill the tire with the correct air pressure, and then quickly rotate the tire back down to the 6 o’clock position.

Ballast Box
Even with the rear tires ballasted with liquid it is not a bad idea to still use a ballast box filled with field rocks on the 3 point of your compact Kubota. If you do not have a ballast box then carry an implement (securely!) back there to add weight and stabilize your machine, especially if you have a front end loader. The neighbors might think its strange having a rototiller mounted on the back of your Kubota as you push a mountain of snow down the driveway on a 20 below day, but fear not! There are some of us out there that know you are doing it right and playing it safe!

Service Department Vic

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6 Reasons to Liquid Ballast your Kubota’s Tires
Comparing Types of Liquid Tire Ballast

So after thinking about it and considering the reasons to ballast your Kubota’s tires, you might find yourself wondering what liquid makes the best ballast. There are a few options available and depending on your climate, budget and access to some of these liquids in bulk quantities.

Liquid Ballast Comparison Table

*using CaCl2 is low cost if containment tubes are already available and installed, otherwise this is a high cost option

Water
Water has been used as ballast inside the rear tires of tractors operated in warmer climates for years. In geographical locations where freezing occurs, an additive is necessary to prevent the water from becoming an ice block inside the tire. Ballast that does freeze inside the tractor will make those tires unstable and general operation of the tractor unsafe. Water is the least expensive form of liquid ballasting and weighs 8.3lbs per gallon.

Advantages
• readily available
• no cost
• safe to use – non-toxic, non-flammable
• easy to install into tires

Disadvantages
• not suitable for cold climates

Calcium Chloride
Calcium chloride, CaCl2, in powdered form can be mixed with water to produce a liquid that will resist freezing up to -50F, depending on the strength of the concentration. Calcium chloride weighs about 11.5lbs/gallon mixed, so more ballast weight is achieved in the same volume, allowing a heavier ballast. This type of liquid ballast is a highly corrosive mixture so care must be taken in handling this product. CaCl2 should be installed into tubes regardless of whether or not the tire on the tractor is tubeless. Without being contained in a tube the mixture will rust the rim flange area right out.

Advantages
• easily obtained in large quantities
• high weight/volume ratio (almost 40% more than water alone)
• very high freeze resistance

Disadvantages
• care taken when used – corrosive mixture
• must be installed into tubes – extra cost
• if installed without tubes corrosion/rust of the rim will occur
• puncturing a tire filled with CaCl2 will spray rust-causing mixture everywhere, damaging sheet metal and vegetation

A typical 50lb bag of calcium chloride with inset image showing powder consistency.

Ethylene Glycol Antifreeze
Antifreeze, mixed 50/50 with water, and installed into your Kubota’s rear tires, will provide the same amount of weight per gallon as water and will resist freezing to approx -40F. Ethylene glycol antifreeze is classified by Canada’s Environmental Protection Agency as hazardous waste after it reaches the end of its useful life. Care must be taken when disposing of this type of ballast – and in the case of a tractor tire, there will be a lot of mix to deal with.

Advantages
• easily obtained in large quantities
• high freeze resistance
• safe to mix – non-flammable but is toxic if ingested

Disadvantages
• hazardous to the environment, animals and people – care must be taken regarding its disposal
• could get costly if your only source is 1 gallon jugs at a Walmart

Propylene Glycol Antifreeze
Propylene glycol is known as a non-toxic or people/animal friendly antifreeze. Besides its antifreeze properties, it is actually used in many cosmetics, pharmaceuticals, shampoos and as a food additive. Dow, who manufacturers 35% of the world’s supply of of propylene glycol, reports that in the United States, 22% of production is used for antifreeze or de-icing. When installed into your tires as a ballast in a 50/50 mix, expect similar properties to ethylene glycol, high freeze resistance with ballast weight similar to that of water alone. AMSOIL makes this type antifreeze available by the gallon or 55 gallon drum.

Advantages
• easily obtained in large quantities
• high freeze resistance
• safe to humans, animals and vegetation, non-flammable, non-toxic and biodegradable

Disadvantages
• more costly than plain old toxic ethylene glycol – sources we used, quoted prices of 33%-120% more per gallon

Windshield Washer Fluid
Washer fluid, installed right from the jug is freeze protected to about -20F and provides about the same ballast weight properties as water does. Washer fluid has some of the same chemicals in it that antifreeze does, but at milder concentrations. Disposing of gallons and gallons of washer fluid, as in the case of tire ballast, would require care.

Advantages
• easily obtained in large quantities
• low cost
• adequate freeze resistance
• no mixing required – use as is, non-flammable but is toxic

Disadvantages
• hazardous to the environment, animals and people – care must be taken regarding its disposal

Methanol
Methanol is highly flammable and if you decide to use this product it must be mixed with water to make it so you do not blow yourself up while mixing it, installing it, or driving your tractor with it in there. Depending on strength of mixture, methanol and water is good to around -15F temperatures. We are not recommending the use of methanol and water because of the danger – but it is an option available for tire ballasting.

Advantages
• easily obtained in large quantities
• adequate freeze resistance

Disadvantages
• extremely flammable
• mixing required with water
• hazardous to the environment, animals and people – care must be taken regarding its disposal

Beet Juice
Beet juice, a liquid byproduct made from de-sugared sugar beets. This food grade product is available in the US under the trade and brand name, RimGuard. This liquid weighs about 30% more than straight water and resists freezing to about -35F. Best of all, it will not solidify until the temp drops to -50F. Natural, non-corrosive, safe to the environment and humans. If beet juice is available in your location, we believe this your best bet – safe to use and provides extra ballast weight.

Advantages
• high weight/volume ratio (about 30% more than water alone)
• very high freeze resistance
• anti-rust properties
• a natural product – environmentally friendly and safe

Disadvantages
• may not be available in all locations

Polyurethane Foam/Flat Fill
This ballast method is essentially a run-flat polyurethane fill that is injected into the tire through the valve stem. Two liquid components are pumped into the tire and they react with one another so that 24-36 hours later, you are left with a solid rubber core – the air inside the tire is completely displaced. The term “foam” is a bit misleading – the core is actually very much a black solid. It is sometimes called foam because air bubbles are injected into the mix to control the density of the end product.

This ballast method obviously adds serious weight gains to each tire and also has the nice benefit of eliminating flat tires and associated repair costs. Because the tire is run-flat there is no risk of corrosive/toxic ballast spraying all over your tractor and scorching vegetation if you do spring a leak. You will have to find a dealer near you that performs this service (Brannon Tire in Stockton, California for example).

Advantages
• high weight/volume ratio (about 20-50% more than water depending on type of fill)
• cannot freeze
• tire is run-flat
• simple – have it done once, ballasted forever

Disadvantages
• may not be available in all locations
• high cost – prices range around $0.95-1.25 lbs injected, or $300+ per tire
• tire must be cut off rim after tread wears out – best for new or nearly new tires
• if performed on steering tires, heavy duty weight gains will put more stress on steering components
• no air in tires to absorb humps and bumps so you will get a very rough ride – could be jarring for long distance travel

Have experience using some of these ballast types? Write us a comment below!

Service Department Vic

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