So your going to look at a used tractor to buy but you don’t know what to look for. This article covers the main points of a tractor inspection.
**When looking for a used tractor, find the tractor that fits your needs to start with. If you need a loader find a tractor with a loader. Loaders are hard to find for older tractors after the fact.
This is a long article and probably best to read and just take some notes with you.
1st thing is ask for maintenance records. A great owner will have records of things they have done over the years to maintain the tractor. Having said that though i have bought lots of tractors over the years and it is rare someone actually has anything regarding maintenance. Sometimes you’ll get a piece of paper with a bunch of scratch on it over the years. That’s better then nothing and at least shows they did stuff.
HOURS. Lots of folks put a lot of stock in hours on a tractor. While it is important it is by far not the most important part of an inspection. Now obviously buying a 5000 hour tractor regardless of maintenance is up there in hours and will have some wear and tear. Ive purchased 500 hour tractors that were ragged out and not worth repairing and i have purchased 2500 hour tractors that still looked and worked like a new one. Maintenance and care is more important than hours.
When you schedule a time to look at the tractor ask the buyer not to start the tractor that day. You want to see how it starts from a cold start. If the engine is warm when you get there you cannot determine if the heating system (Glow plugs) is functioning properly among other things such as low compression. They may be using ether to start it and when its warmed up it starts fine on its own. If they refuse then pass on that tractor.
So lets dive into the particulars.
ENGINE.
Engine is a critical component of the tractor that is easy to overlook important areas. Check oil. Even freshly changed oil in a diesel engine will be black in a matter of minutes. Its just the nature of the beast. When was it last changed? Does the filter look new and clean or worn and dirty? Ive seen many cases people say they changed the oil recently and maybe they did but the filter looked like it had been on there for years, painted peeled and rusted. Kubota paints engines and transmissions with the filter attached so if they filter is still painted grey then it has never been changed. Any water droplets on the dipstick or milky looking oil means water/coolant is getting in the crankcase. Causes of that are cracked head, blown head gasket, cracked block and rare occasions water getting in the intake. Smell the oil. If it smell like fresh diesel then diesel is leaking into the crankcase typically either mechanical fuel lift pump or injection pump. Is the oil level too high? Maybe they overfilled it but could also be diesel or hydraulic oil leaking into the crankcase. Oil level too low is seal leaking or worn internal parts and it is burning oil. Check for smoke. Diesels will puff some black smoke on startup and will puff a little under load or when you open the throttle to increase rpms. That is normal. Outside of that there should be no smoke coming out of the exhaust. White smoke indicates water/coolant burning and a cracked head or blown head gasket. Blue smoke indicates burning oil. Grey smoke indicates unburned fuel and excess black smoke is too much fuel. Black and grey get confused a lot. Grey smoke can be low compression, bad injector, and/or problem with injection pump.
Knocking. Diesels knock that’s just how they are. To the untrained ear it can be easy to miss a problem. Things that are not normal are valve ticks which are lighter and higher pitched and are typically not a big deal, they just need adjusted. Injectors can knock which is not normal and typically accompanied by grey smoke and rough running engine. Lower end knocks are typically spun bearings and will sound like a hammer knocking on the block near the bottom. There are other things that can cause knocks but again some diesel knock is normal and its hard to explain the difference in an article. If you feel its questionable have someone experienced go with you or have a shop inspect it.
Coolant system. Cooling system is very important and is often neglected. All tractors will have some sort of screen on the side of the radiator that air sucks in. That screen should be clean and free of debris. The fins in the radiator should be clean and free of debris and not all bent up. Some models have reservoir some don’t. Check the radiator and reservoir for coolant and cleanliness. Models that have a reservoir you can watch the coolant with the engine running and make sure there are no bubbles indicating possible blown head gasket or cracked head. Some older B models do not have a water pump and rely on thermal siphon where the hot coolant rises forcing the cooler coolant down thus circulating the system. Its not as efficient as a water pump but it does work. These systems are more prone to problems when neglected. BX models need to be cleaned frequently. The radiators tend to get clogged up on the outside and are not properly cleaned. Make sure the fan is operational and in good shape. Try wiggling the fan and make sure the pulley attached to the fan isnt moving. That would indicate a water pump bearing going bad assuming all the bolts are tight. There is a weep hole on the bottom of the water pump. Check for fluid leaking out underneath the water pump from this hole. This would indicate seal and possibly bearing failing on the water pump.
Blowby. Blowby is an often misunderstood term. All diesel engines have some level of blowby. Blowby is combustion gases blowing by the piston rings creating a positive pressure in the crankcase. There will be a crankcase vent, which is typically in the valve cover and usually has a tube attached to it going down the side of the engine. The vent allows this pressure to escape so you don’t blow seals in your engine. While the engine is running watch this tube. Little to no smoke coming out of the tube is normal. What is not normal is excess smoke or oil spitting out the tube. Excess smoke and/or oil coming out can be as simple as the engine oil level is too high but typically means the rings are worn out and too much pressure is escaping the combustion chamber into the crankcase and in need of a rebuild.
Transmission / Rear Axle
Check the fluid level. For the most part B and BX have an oil dipstick somewhere on the transmission. It can be under the seat or in the rear behind the seat. Make sure at least what you can tell is clean and not dark or milky. Dark would be old oil with lots of contaminants and milky would be water in the oil. It is best to check it after it has ran for a few minutes as oil and water will separate. New hydraulic oil does look brown in a container but on a dipstick it should look fairly clear. All Kubota Hydrostatic tractors should have Kubota UDT or UDT2 fluid in them, I know some will have different opinions about this but ask anyone who actually works on these tractors about the damage that can be done using other brand fluids. I know its expensive but a new hydrostat unit is far more expensive. Gear drive tractors are fine with a good quality hydraulic oil.Check for leaks. Common leaks are axle seals, pto seals, shift boots torn on gear drive models, and hydraulic lines. Luckily none of those are hard to fix though. Make sure the 3 point lift arms raise and lower. Most models there is a knob under the seat for adjusting the lowering speed, if it lowers very slow try adjusting it. There is no down pressure so if the arms are down you should be able to lift them up with your hands. Check brake function. Even on a hydrostat it is imperative to have working brakes. If nothing else for parking brake. Older models will have a dry external drum brake, while late 90’s and newer will have internal wet brakes. Many models will have a hub on the axle that the wheel bolts to and is adjustable to narrow or widen the wheels. These hubs can wear over time and cause a wobble in the tire. Good news is new hubs are not expensive and easy to replace. For models with a clutch check to make sure there is no noise when you push the clutch pedal down. This could indicate bad throwout bearing or pilot bushing. Either requires you to split the tractor to repair. If possible check the Differential lock. If there is a tree around you can put the bumper against and switch to low gear 2wd and try to move forward. One tire should spin. Now try it again with the differential lock depressed and you should get both back wheels spinning.
Gear shift models check for noise in all gears, high and low, forward and reverse. There should be minimal to no noise coming from the transmission in any gear. Make sure you can put it in each gear with the clutch pedal down with minimal to no grinding. Now these are not synchronized transmissions so a minimal grinding here and there is nothing to worry about. Make sure you can swap between high and low and 2wd and 4wd. Again these are not synchronized gears so in some situations you may have to rock the tractor just a little to accomplish this.
Hydrostat models make sure the tractor drives forward and reverse in high and low. All hydrostatic tractors have a whine noise to them. It should not be excessive and tractor should feel like it moves with ease as you push the pedal. There will be more whine in high than low and more whine when traveling up an incline vs level ground. The hydro pedal does not work like a gas pedal. It is an infinite gear ratio, The less you push the pedal the lower the gear, the more you push the pedal the higher the ratio gets thus moving faster, but that also works against you in some situations. For instance going up an incline the tractor will move more at ease with just a little bit of pedal as its in a lower gear whereas if you push the pedal all the way down your in a higher gear and it will take more to get up that hill, while lugging the engine and transmission.
Steering
B models – Check for play in the steering. Play can come from the steering gearbox itself, the pitman arm, drag link, knuckle or tie rod or a combination of all of it.
There are 2 types of steering setups in the B models. 1st is Manual steering and is all mechanical and uses a worm gear, ball nut and sector shaft to move the pitman arm. 2nd is Power assist or power steering which is a mechanical/ hydraulic system. I wont go into all the components here but basically a mechanical system with hydraulic assist. With these systems you still have manual steering should the engine die or you loose hydraulics. Check for leaks at the steering gearbox. Leaks are most often from an inner seal and not the top dust seal that people say ” its only a $10 seal” .
BX models use hydrostat steering. This is all hydraulic controlled. There is a steering controller under the steering wheel and then hydraulic lines going to a hydraulic cylinder down by the wheels. Check for operation and leaks. Most common issue is the hydraulic cylinder at the wheels leaks internally and the steering isn’t as responsive as it should be. It is a simple fix either rebuild or replace the cylinder. In this system you will have little to no steering if the engine dies or you loose hydraulics.
Front axle
Check the front axle for play. If possible jack up the front end and look for play in the bevel cases and hubs. Check the fluid level in the axle and make sure it does not have water in it. on 4wd models if possible while doing the test on the differential test up against a tree, put it in 4wd and make sure at least one tire starts spinning. It is an open differential so most likely only 1 tire will spin. This is normal. Check for leaks at the pivot point where the axle mounts to the frame as well as wheel hubs, and gear cases,
Loaders
Look for leaks at hoses and cylinders. Neither are hard to fix but can get costly if there are several leaks. Look for pitting on the chrome of the cylinder rods. Pitting will eat up seals fast and cause leaks in the cylinders. While your looking over the tractor lift the loader up off the ground a foot or so and curl the bucket. The bucket should stay curled and the loader should stay up in the same position. Now all cylinders leak down over time. but in the little bit your looking at the tractor there really shouldn’t be much if any leak down. If so it could just be cylinders leaking internally or could be the control valve.Uncurl the bucket some and try to wiggle it up and down as if you were curling and uncurling the bucket. On an older tractor there likely will be some play on all the pins for the bucket, arms, and cylinders but should not be excessive. A little bit of play is fine but if its sloppy and wiggling all over the place then it will need attention and shows a history of not greasing the loader. Make sure all functions work up/down and curl/uncurl. Make sure all the bolts to the loader frame are there and look tight.
Backhoes
Basically the same as the loader. Check for leaks on cylinders and hoses. Check function of boom, dipperstick, bucket, swing and outriggers. Lower bucket to the ground and give it a little down pressure and watch the area where the boom connects to the platform. There is a big pin there that connects the 2 parts and has a tendency to be worn out and loose from lack of greasing. Again a little play is fine but excessive will need attention. Uncurl the bucket some and give it some shakes in all directions. It should not have excessive play, but a little is ok.
Electronics.
There is little to no electronics on B and BX models earlier than 2014 and even after that only a few models that are larger than 25hp will have a computer system due emmision regulations. Check safety switch operation, dash guages and lights, engine start/ stop, lights and flashers.
Thank you for reading the article. Should you have any questions or feedback please contact me the via the “Contact Us’ page.