Tractor rebuild project

[jandpp]

I thought I would share a tractor project that I have been working on. I've been inspired by several other series of posts about tractor rebuilding and was thinking that that would be great learning experience for me.

In Thanksgiving 2009, I purchased a Kubota B8200 HST to help build a horse pole barn for my wife. After breaking ground in December and working every spare moment, every weekend, all vacation, many, many evenings, the barn was completed in September 2010. During that time the 8200 was indispensable lifting, moving, and pulling. I got it from a local repair shop. The head mechanic had just rebuilt the engine and I bought it from him. It basically only had wiring to start it and fire the glow plugs. I replaced the wiring for the lights, flashers, and dash and also replaced the tach/hr meter cable and then the spinning sender unit on the front of the engine attached to the fuel cam. That all was fun so I've been looking for something a bit more challenging. Especially now since I have a nice large space in which to work since the barn is completed.

In October my wife found a Kubota L2900 GST with loader on craigslist. (I've got a great wife!) It had a seized engine. Everything else was supposed to be running just fine but it's kind of hard to tell when the engine doesn't turn over. The hr meter said 580 hrs. The starter engaged but wouldn't turn the engine. There were no leaks. The owner suspected a seized connecting rod bearing and he also gave me a set of new seals for the front axle. It was a great price and I bought it on impulse. Kind of high risk in that it was thousands of dollars and I've never done any real engine work. Worse case I'd have chalk it up as very expensive entertainment.

 

[jandpp]

I found a nice engine stand on Craigslist, purchased the owner's manual and shop repair manual, downloaded the part diagrams from Messicks, bought 2 books on engine repair one engine rebuilding, the other about diesel engines, and augmented my tool set with some larger Craftsmen wrenches. I can't afford the Snap-on stuff and I really have a problem with cheesy tools from the likes of HF. Also scanned TBN for any info on L2900. Hmm, front seals seem to be a common problem.

After getting the tractor home the first task was to remove the loader. No engine function = no hydraulic function. This was one of the hardest parts of the entire project. The previous owner had one of the back pins out but not the other one. The loader was kind of skewed binding up the other pin like you wouldn't believe. I was pulling on it from all directions with my other tractor. There was no access to poke the pin out from behind and it took hours to remove. Finally figured out that if I spin the pin around and around by banging it a million times with a large hammer, it would finally spin out. I was very concerned that the loader had been twisted out of alignment by some nasty act like rolling the tractor. Figured I'd save that problem for another day.

I rolled the tractor in the workplace and began to plan the cracking adventure.

 

[jandpp]

I examined the engine closely as I drained the fluids. The tractor overall is in good shape for it being 13 yrs old. The gray paint was still shiny on the sides of the engine. Interestingly, the paint is cracked on the bolts on the oil pan, valve cover, and a few other places. Hmm, I'm draining the antifreeze and oil and they look really fresh. Brown oil and green antifreeze. Whoa, what's this? An old head gasket tucked up underneath the gas tank. This is turning out to be a real mystery. According to the previous owner, there was a whole list of people who responded to the Craigslist ad. I was the second person who called and the second to see it. The first guy wanted to buy it but he didn't have a deposit ready. I didn't ask too many questions and just plunked down the money.

 

[jandpp]

Cracking the tractor wasn't too bad but I'd have never been about to figure it out without the shop manual. I had to remove the entire steering pedestal along with linkages, hydro lines, fuel talk and filter, electrical connections, etc. Worst part was the power steering couplings at the base of the steering pedestal.

 

[jandpp]

After that, you support the back of the tractor with a jack, support the front with something else (a handy piece of equipment like the one seen in the picture below), remove the bolts that connect the clutch housing to the engine, and pull it apart. Very exciting. BTW, I'm taking a gazillion pictures along the way and writing reassembly notes in a notebook so that I have a chance a reassembly. At this point I'm thinking the probability is low!

 

[jandpp]

Remove the pressure plate, clutch, and freewheel, and mounted the engine on my engine stand. Sure enough that sucker is seized. No amount of force is turning the crank. On the positive side, makes it easier to bust loose the freewheel bolts.

The hyrdo pump is much larger than on my B8200. I hope that translates into greater loader lift capability.

For those interested, this is a D1503 Kubota engine - 3 cylinder, 1.5 liter, 30 hp model. Non turbo. This is a popular engine series that includes a D1403, 1503, 1703, 1903 and 2203. Maybe a few more. Surplus Center has a new 1903 42 HP model for $3800 or even a turbo 2203 for $5k. Should I put one of those in there instead?

 

[jandpp]

I've encountered my first tool problem. There is a big nut holding the pulley on the front end of the crankshaft. Worse, the crank extends out well beyond the nut. Not only can one not use a regular flat wrench on the nut because it's recessed in the pulley, but one can't use a regular socket either because of the extended crank. Note that the end of the crank is splined and it is torn up. Nothing goes on the end here and I'm not the one who apparently grabbed it with vicegrips. No rental places had a deep 32mm socket so I had to order one online. Also bought a 3/4" socket handle to drive it.

This nut was a bear to get off. The book says to retighten it to 160 ft/lbs. It took both my neighbor and me to break it free one person to hold the wrench on, the other to twist it. The socket thickness is a bit too great to get good purchase on the nut inside the taped indentation in the pulley. But we got it. Even with that great force, the engine crank didn't budge. It's really frozen.

 

[Tommy V]

Excelent work so far. It is never as difficult as it seems before you actually start. Cracking good...is someone else on her a Wallace and Gromit fan?

 

[jandpp]

Removed the head, push rods, lifters, oil pan, injector pump, oil pump, and camshaft. Pulled out pistons. Crank still wouldn't turn. Has to be some type of crank bearing problem

Just FYI if you are interested, the frontal picture shows the engine with the gear cover removed. The top left gear is the injector pump cam, the top right gear is the valve camshaft, the middle gear is the idler gear which connects the crank to the camshafts. The bottom geared thing is the oil pump.

The timing marks were very easy to see on the gears so it was pretty simple to ensure that cams were aligned with the crank.

Even though there is no spark, a diesel engine still has the notion of timing. In this case, timing refers to the time at which the fuel is injected into the cylinder. For these engines, timing is adjusted by adding or removing shims underneath the injector pump plate. This varies the distance between the fuel cam and the injector pump followers. Adding a shim delays or retards the fuel injection timing.

 

[jandpp]

Here is a few pics of the injector pump and fuel system.

The first shows the injector pump. It is the unit right above where it says STOP. You can kind of see the gasket like shim where it attaches to the block, right below the air bleed value.

The second pic shows the governor arm. It has two little springs that run internally and attach to the throttle assembly. Those little springs are tricky. The third pic shows the fuel cam gear inside the front gear cover. Note the 3rd little spring. This is the easier of the 3 to remove and reattach.

 

[jandpp]

Problem root caused!

Removed the crank assembly and found the problem. The middle connecting rod bearing had fused to the crank journal. Wow, the previous owner said it was a connecting rod bearing and he was right. I still don't know a lot about engines but I'd think there could be many things that could cause engine seizure. How'd he know that was the problem?

The lighting is bad but the first pic shows the scoring and melted metal on the crank. The 3rd picture shows what connecting rod bearings look like. Really just C-shaped metal sleeves. I was expecting something a bit more elaborate.

 

[jandpp]

I got my first cost scare when I priced a new crankshaft. $1700!

I took the engine parts to an engine machine shop to see what needed to be done. Hoping that they can tell me what to do and do something with the exiting crankshaft. BTW, the place is The Engine Shop in Longmont, CO. Great guy.

To make a long story short, the machinist thought that the connecting rod bearings were new. They had been installed incorrectly or not pre-lubed and they seized up right away. He said that they did exactly what they are supposed to do. If there is excess friction they are supposed to seize up and kill the engine motion rather than let something catch and bust out of the engine block.


One cylinder was .010 oversize, one .020 oversize, one .040 oversize. The machinist rebored the cylinders .020 oversize first putting a sleeve into the cylinder that was .040 oversize. He also reground the valves and was able to polish off the messed up the crank journal. I bought .020 oversize pistons and rings, gasket set, and a new oil pump just because I had everything opened up. I probably paid more than had I purchased a rebuild engine but I wanted to rebuilt the engine myself. Heck, if I would have had to purchase a new crankshaft, that would have cost more than a rebuilt engine.

 

[jandpp]

I think that this project is interesting not only for the learning experience but the mystery of how the engine got in the condition that it's in.

Recall that many of the engine bolts had been removed at one point and I found a used head gasket. However, the frame bolts had not been moved before (unless they were painted over afterward which is unlikely) nor had many of the bolts around the steering pedestal. I suspected that someone had replaced the head gasket while the engine was still in the tractor. Further evidence of such work were the weld marks on the upper frame. See picture.

But with the machinist view that the connecting rod bearings were actually new, it appears that someone had tried to replace them with the motor on the tractor. And unfortunately, did it wrong. Poor guy. Did this work, filled it with fluids, started it, and siezed up probably almost immediately. Guy probably got fed up with it and sold it.

The second question is why an engine with less that 600 hrs would need this kind of work and what caused the cylinders to be enlarged. The machinist proposed that it was run without changing air filter or even without filter for extended period of time.

 

[jandpp]

Just in case I wasn't clear, I think that the weld marks indicate that someone cut the frame to get access the engine rather than go through the extensive labor of removing the pedestal and cracking the tractor. Then they welded the frame back together.

 

[jandpp]

The machinist allowed me to install the crank bearings, pistons, and camshaft in his shop under his supervision. I then brought the block home and put the rest of the engine together and painted it.

These pics show the engine fresh back from the machine shop. The first pic is right after I installed the rear main seal. The big gear on the left side drives the hydraulic pump.

 

[jandpp]

More pictures of the reassembly and final, newly painted engine.

 

[jandpp]

I reinstalled the engine back in the front half of the tractor hooking up the radiator, fuel, and electrical console. Turned the key and the glow plugs fired. Turned the key again and blew the main 40amp fuse. Rigged up a 40amp circuit breaker and blew the breaker every time I moved the key to start. So I wired up a temporary switch between the battery and starter/solenoid connection. Used the key to ignite glow plugs and used switch to engage starter. The engine turned. And turned and turned. The air bleed valve didn't seem to be doing much so I removed one of the injector lines. After a lot of cranking, fuel finally began coming out of injector line. Hooked it back up and the engine sputtered and came to life! Sounds great. It was pretty thrilling I must admit.

Major mistake #1 coming up. I brought my wife out the next morning to show it off to her. I went through the key and temporary switch process. It was a little hard to start but it fired and sounds fantastic. She was impressed but for some reason lost interest after about 10 min or so. Hey, I could have listened to the thing for hours. I let it run about 20 minutes and then turned it off. There was still a clicking sound after I turned off they key and shut the engine down. Oh no. What is that? Something rattling around in the engine? I go over to the other side. Sounded like what a car sounds like when you try to start with a very low battery. Oh no. In my excitement showing my wife the engine start, I forgot to turn off the temporary starter toggle switch! The starter had been running for 20 min and drained the battery. Not only that but it was blistering hot. Not only that but when I added power from the car battery, the starter still wouldn't turn . I'd burnt out the starter. Stupid.

I left for work and called my local dealer to inquire about a new starter fearing the worst. Even that fear was on the low side. $650 for a new starter. Ugh. And it would take a week to get here. I said I'd have to think about that. I'm a lucky guy because I found a place online that sold me a new one, same brand, for $89. I even splurged and paid an extra $60 for overnight delivery.

I got back home and tried to start it again with the original starter. It worked! I hadn't burned it out after all but it had just been too hot before.

I combined the front and back of the tractor, installing the electrical connections the proper way and the key now functions properly. Not sure what the problem was. The key in start position shouldn't have done anything. There are two lock out switches, one on the shuttle shifter and one on the gear selector. I didn't have those connected previously because they were on the back tractor half harness. Don't know why the result would be fuse blowing rather than no action. But problem solved when all wires connected.

Several days later, it was struggling to start and I thought what the heck, I bought the new starter, I might as well use it. I installed it and it turned much faster. The engine now fires right away.

To make myself feel better, I now think that it started slowly from when I first tried it. The starter was probably on it's last legs when I got the tractor and before I ran it 20 minutes straight.

 

[brain55]

Great job.

Brian

 

[Grandad4]

My hat is off to you! That's an inspiring story, with a great outcome. I admire your organized approach, attention to detail and courage. And, in the end, you're going to have a great tractor to be proud of. Thanks so much for sharing it, with pictures, no less. Best wishes as you complete the project.

 

[crbr]

None of these one-uppers with 5000 trucks or 900 Kubota tractors here can top that. Most excellent. Thank you for sharing.