Restoring a Kubota B20 Tractor – Part 5

Lots of progress to update!

Two of the cylinders cleaned up to within spec after surface honing. Cylinder #2 had some very heavy pitting, most likely from water sitting in the cylinder. It needed to be re-sleeved.

Kubota D950 - Ok Cylinders
Kubota D950 - Bad Cylinder #2 with heavy Pitting

I took on re-sleeving the cylinder myself, and it was much more work than I anticipated. I removed the old sleeve by carefully chiseling a slit from top to bottom. I stuck the new one in the deep freezer before installing, but it still took several hours of work in combination with additional ice packs to finally drive it in. If I ever to another one of these, I am definitely going to use dry ice.

Driving in New Cylinder Sleeve

Another surprise was to learn that Kubota cylinder sleeves are not bored to final size, due to the amount of force they require for installing. I was not able to find a local machine shop that could do the work that wasn’t already backed up several months. I decided to try boring it myself using a neighbors hone that he was sure could also bore. I was skeptical, but to my surprise, with some patience and frequent bore measurements it worked great! This wasn’t the common inexpensive cylinder hones. It had gear driven racks that applied the pressure to the stones and kept them parallel. After several hours of working with it, I had a cylinder within 3 thousands from top to bottom, and side to side, which is within the factory specs.

After flushing all of the honing grit out of the crankcase really well, I changed out all the crankshaft main bearings and seals. I also polished the crankshaft journals.

Kubota D950 Crankshaft

I ordered the rebuild kit that included new pistons along with the rings. Here is a shot of the crankcase all cleaned up right before putting the oil pan back on.

Kubota D950 Crankcase with Oil Pan Removed

Next, I resurfaced the engine head and ground and polished the valve seats. One of the exhaust valves needed replacing due to stem wear.

Kubota D950 Engine Head

While putting everything back together, I think I found the cause for the original overheating problems. The T-Stat housing had a crack all the way through, in a location that was almost impossible to see when the engine was assembled. It was a pretty expensive part to replace, so I decided to braze it with Allumiweld rods, which are made for repairing aluminum.

Cracked Kubota D950 T-Stat Housing
Repaired Kubota D950 T-Stat Housing

And the final post of updates for now, I have the engine re-assembled and have painted it with primer. It will also be getting a coat of the Kubota Dark Grey Acrylic Enamel before installation.

Kubota D950 Prepped for Paint
Kubota D950 Primer 1
Kubota D950 Primer 2
Kubota D950 Primer 3

I am now working on cleaning up and painting the rest of the tractor before putting everything back together again. If anybody knows a good source for Kubota Decals, please let me know!

Click here for Part 6 on the Kubota B20 rebuild.

Troubleshooting an Engine Noise

I developed a new engine noise after a high speed run on my 2004 Yamaha Grizzly 660.

In the video I will take you step by step through my process of troubleshooting and how to isolate the cause of the noise, and then assess the damage. I also demonstrate how to use a mechanics stethoscope, check for loose valves, check spark plug color for ignition issues, how to check valve timing, and several other common issues while we looked for the issue.

Continue reading Troubleshooting an Engine Noise

Restoring a Kubota B20 Tractor – Part 4

I repeated the compression test because I didn’t record the numbers before. In order to perform a compression test (using the injector holes), you will need to remove:

  • Air Filter Housing
  • Metal Injector Lines
  • Fuel Overflow / Bleed Line
  • Metal OverFlow / Bleed Line Rail
  • Injector Nozzles (make sure to remove the copper gasket from the bore for each one as well)

At this point you can test the compression of each cylinder. While cranking the engine, be sure to pull and hold the engine shutoff rod, so the injection pump is not squirting diesel fuel.You can optionally disconnect the glow plugs power wire to conserve battery as well.

The values I read for each cylinder was from back of engine to front (dry):
80 PSI – 160 PSI – 160 PSI

Since the #1 cylinder was especially low, I squirted some oil in the cylinder and repeated (wet).The value rose to 150 psi, which is a good indication the issue is with the piston rings, and not a valve issue.

The service manual spec for allowable range on compression is 337-448 psi, so all three cylinders are well below spec.

Kubota B20 Engine

At this point I pulled the head to check for any signs of damage to either the head, valves, or the pistons.

To remove the engine head on this tractor, you will need to (starting with parts already removed for compression test above):

  • Drain Oil & Coolant
  • Remove Air Filter Bracket & Fuel Filter Mounting Bolts
  • Remove Firewall Mounting Bracket Bolts to Head
  • Remove Exhaust Manifold (optional)
  • Disconnect Fuel Supply Hose to Injection Pump
  • Remove Air Intake Manifold
  • Remove Glow Plugs
  • Remove Top Radiator Hose
  • Remove Top Mounting Bolt on Alternator (and swing alternator out of way)
  • Move Fan Belt OfF Pulley
  • Remove Valve Cover
  • Remove Valve Rocker Arm Assembly
  • Remove Push Rods (inspect to make sure they are all straight)
  • Remove Head Bolts
  • Lift Head Assembly from Engine

The engine is quite crusty with carbon deposits, but I don’t seen any signs of head, piston, or valve damage yet. I will post a follow up again once I have pulled the valves apart and cleaned everything up for a more thorough inspection.

Kubota B20 Valve Cover and Rocker Arms Removed
Kubota B20 Engine Head Removed
Kubota B20 Underside of Engine Head

Click here for Part 5 on the Kubota B20 rebuild.

Restoring a Kubota B20 Tractor – Part 3

Getting back into this project. We have moved since I started this project and now have a garage bay I can use to continue working on the tractor. I was never able to get it to fully fired up. It would sputter and almost catch but never quite start. I finally did a compression check and was seeing low compression on all three cylinders, with one very low. I am guessing there was some engine damage due to overheating issues it was having back when it was running last.

Since it is going to need a rebuild of some sort, we loaded it up on my trailer and brought it back to my house where I can work on it in the garage.

Loaded Kubota B20 onto trailer.

Once back at my house, I needed to figure out a way to raise the bucket and hold it there so it wouldnt guoge the concrete. Many of the hoses are leaking, so I needed an external way to hold it up. I used a floor jack to lift the bucket off the ground, and a scrap board placed into the linkage to prevent the hydraulic cylinder from collapsing back down worked very well!

Lifting and holding bucket up with no power and leaking hoses.

Safely in the garage so I can start the engine tear down.

Kubota B20 before engine tear down.

She has definitely seen some wear, and sitting outside has taken a toll too. These pics will hopefully serve as some good “before” pics once I get it back up and running and cleaned up!

Kubota B20 weathered seat.
Kubota B20 weathered engine compartment.
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Kubota B20 weathered 3 point hitch

Click here for Part 4 on the Kubota B20 rebuild.

How To Build a Large Solar Generator – Part 3 – Component Mounting

This is the third part in our project series How To Build a Solar Generator. In this part, we will be mounting all of the components into our case, as well as some of the preliminary wiring.

Continue reading How To Build a Large Solar Generator – Part 3 – Component Mounting

The Amazing Yazoo Mower

Yazoo Mowers are becoming increasingly rare, but they have an almost cult following of fans and owners.  They are very unique in their design, allowing them to have a zero-degree turning radius way before the modern hydraulic zero-turn mower was invented, and they have a gear shift lever that allows quick transitions from forward to reverse.

Continue reading The Amazing Yazoo Mower

Fixing up a 40’s – 50’s Era Chevy Pickup Bed Trailer

We just recently moved to a new property, and tucked away in an old out -building was this abandoned trailer.  I was looking for a trailer small enough for the four wheeler to pull, and while this will need a little fixing up, I think it will be perfect for the job.

The trailer was full of junk, had a flat tire with one wheel partially buried, and   mouse nest through-out the inside of the differential. It had definitely been sitting a while! Looking at the body shape and construction, it was originally built from a 47′- 54′ Chevrolet Pickup!

Continue reading Fixing up a 40’s – 50’s Era Chevy Pickup Bed Trailer

Restoring a Kubota B20 Tractor – Part 2

You can find part 1 on this rebuild here.

Update: I have tires and wheels on the Kubota B20 and aired up. Was able to get 3 of the 4 to hold air with some tire slime. Front left still has a slow leak that I am hoping will seal up once I get it rolling.

Kubota-b20-7.jpg

Changed the engine oil, oil filter, air filter, fuel filter and radiator fluid.

Engine was completely seized and would not turn over. Removed the injectors and squirted sea foam and engine oil into the chambers to let sit for a couple days. Still wouldn’t crank over with the starter so I used a wrench on the flats of the crankshaft / hydraulic pump shaft coupler to work it loose.

Kubota-b20-8.jpg

Also needed a new fan belt. Side-note – Not an easy job on these machines. If I ever need to do a belt on a machine set up like this again, I am using one of these:

Engine now cranks over and after lots of working the air out of the injector lines sounds like its firing on one cylinder, but not enough to start. It was in the low 40s (F) when I was attempting, so I plan to give it another try on one of the upcoming warmer days.

Part 3 on the Kubota B20 Rebuild.

Restoring a Kubota B20 Compact Utility Tractor and putting it back to work!

A friend of mine has this tractor that was been sitting unused for several years. It ran when it was parked, but at the time it was having some overheating issues, as well as we suspect at least one of the injectors was leaking down causing a surge of heavy smoke for a few minutes when it would first start up.

I am going to go through it and get it back up and running. Once I get it back operational again, I may also consider setting it up to run on waste fuels such as used vegetable oil, motor oil, etc.

Kubota B20

First up is get the front tire back on it (was borrowed to be used as temporary spare for a different tractor),new battery, and get the supplies together to change out the motor oil, and coolant.

Kubota B20

It definitely has been sitting for a few years!

Kubota B20
Kubota B20

The hours meter has definitely turned over at least once. I am also not sure what the expected lifetime is on these Kubota 3 cylinder diesels.

Kubota B20 Hours

The engine compartment isn’t too bad. There is a mouse nest in the coolant overflow bottle though!

Kubota B20 Engine

Should be a fun project! Click here for part 2 on the Kubota B20 project.