Broken Crank, What to do?

[uofa314]

Hi, I came across this forum while looking for info. We have a 1980 model John Deere 1050 with the 3 cylinder yanmar engine. My dad and I were planting a food plot a few weeks ago and the tractor started making a loud knocking sound. We shut it off (it didn't stop on its own) and hauled it to the local John Deere dealer. We thought maybe it was just an injector or something minor. Well, they called today, and i stopped by to see for myself, it has a broken crank shaft. They found that when they split the tractor apart (separated front and rear end) and the back of the crank with rear rod still attached is just flopping in there. They told us that the crank alone John Deere is $2000.

So, we are trying to figure out what to do. It is a good tractor otherwise. I found a crank for $500 on the Hoye website. Should we just bring the tractor home and rebuild it ourselves? I think we can get all the parts to rebuild for under $2000.

Is there any chance that broken crank damaged the block? If so, a rebuild is out of the question.

Or, should we look for a used engine somewhere? I looked online today, but didn't have any luck finding one.

 

[Dr Dave]

Try Rock Valley Tractor parts, they have lots of JD parts and engines, also Worthngton tractor may have an engine or crank. Did the dealer say the block was usable? How many hours?

Dave

 

[uofa314]

Dr Dave, The dealer stopped once they saw the crank was broken, so we won't know what the block looks like until we get into it. Thanks for the tip on Worthington. They have about any part we could need, even a block if it comes to that. We don't know how many hours are on the tractor because the hour meter doesn't work. We have owned it for a few years now, and only use it to plan a small garden and food plots. We probably don't use it 50 hrs/year. We had just changed the oil, etc. every spring since we don't use it much.

Well, after calling around today, I figured out that an engine for the 1050 is hard to find, but parts to rebuild are available. So, I called the dealer and asked if I could pick up the engine, rebuild it myself and then take it back to them to put back in the tractor. They agreed, so that is the route we are going. I have the engine and will be getting into it tomorrow to see what that damage is.

If the block is good, we are going to replace the crank, bearings, pistons, rings, sleeves, and take the head to the machine shop to get checked out. Should we replace the water and oil pumps as well?

 

[uofa314]

Also, the turbo is shot. The mechanic pointed out to me that it doesn't spin freely like it should. The exhaust manifold is in bad shape, so I looked for one of those. I found a used manifold and used turbo for about $500. A new OEM tubo alone is $1200. I also found that the difference between a 950 and 1050 john deere is the turbo. The 950 has 27 hp and the 1050 with turbo has 33 hp. I could get a new exhaust manifold for a 950 and just leave the turbo off for less than $200. Would it be crazy to do that and give up those 6 hp?

 

[Dr Dave]

Oil pump is a must, water pump would be easy at this time. How about a reman turbo, I would ask your dealer about eliminating the turbo, there may be more to it, injection pump replacement or adjustment? Did Rock Valley tractor have any engines?

Dave

 

[Hooked_on_HP]

Have you ever rebuilt an engine before.Do you know what to look for as far as damage to the block. Do you have a service manual that covers the engine. do you know what caused the crank to brake.Rebuilding a good running engine is fairly easy.When repairing a broken engine there are lots of things to look for. If you know what to look for you can get a good idea of what caused the problem as you are disassembling the engine. If you don't find the problem there is a chance that the rebuilt engine will do the same thing. I am not trying to discourage you, I am just trying to make sure you know what you are getting in to.
Bill

 

[1fastbob]

I am not trying to be negative, but I'll bet the block is trash.

 

[kenmac]

Have you tried Fredricks in NO. AL. If he has a crank you could just drive up and pick it up. Probably cheaper than shipment from Texas. He may have a complete engine or he may rebuild yours cheaper than the deere dealer

 

[ddipert]

Need to find the root cause of a broken crank or you might be in the same situation in a few hour of run time. Eliminating the turbo would be a bad idea. Fuel curve is going to be different, end up with less hp and to rich.

Block could be damaged but I've seen large holes out the side of blocks repaired and worked for years. My guess is you might have some damage around the crank bearing , but would depend on where the crank broke.
Post pictures of the inside of the block after you've pulled it apart.

 

[Kernopelli]

You mentioned that the non turbo 950 and the 1050 share the same engine ( yanmar 3t90J). A close friend just told me about rebuilding his old 950 several years back. As the story went........He ordered a new crank from the local JD dealer. Everything went fine until he tried to join the tractor's split halves back together....they would NOT pull back together the final inch or two. Repeated attempts and much input by others left him literally reduced to tears of frustration. The split tractor would not pull back together. He eventually discovered that there was a "separation in serial numbers" ( of 950's or 3t90 engines, I'm not sure) that left two different cranks available for that engine...... and he had the wrong one. One has a longer tail than the other. After learning this, he cut a short length off the trans input shaft and the halves joined.

Just thought this story may be worth passing along.

 

[kenmac]

Wonder what crank your friend ordered / recieved. My yanmar 3110 (JD 950) is the same as yanmar 3810 ( JD 1050) except for turbo & I believe injector pump timing for a little more fuel

 

[Kernopelli]

No idea on the crankshaft. You bring up something pretty cool, you obviously don't need a turbo to get some extra HP out of that engine because I assume your 3110 is not turbo'ed but is more than the 950's 27 HP.

He just related this story to me about a week ago when I told him I was putting my Mitsubishi K3F back together. He said he initially assumed he had installed something backwards or clutch,flywheel.....something-anything wrong but repeated teardowns proved everything correct. He had several friends come over and look at it and eventually had one of the mechanics from work who worked on all of their Deere equipment come by and go through it completely with the same results. Finally called the Deere dealership and they told him the about the "separation of serial numbers" etc. That is what led him to start doing some type of measuring/marking when he tried to pull the two halves together and he decided it left him with 2 choices.....either order another crank or cut the input shaft. He said Deere had charged him about $1000 for the crank and blamed him for the "mix up" so another crank was out of the question. In the end, the tractor ran fine and he used it in his tree trimming business for several years before selling it to upgrade to a skidsteer.

QUOTE=kenmac;3032082]Wonder what crank your friend ordered / recieved. My yanmar 3110 (JD 950) is the same as yanmar 3810 ( JD 1050) except for turbo & I believe injector pump timing for a little more fuel[/QUOTE]

 

[kenmac]

Well, They say that the 3110 is 37 engine HP. I have never seen any proof ( on a dyno) that my engine is 37 HP. My engine plate list ( I'm going off memory now cause I'm not around my tractor) 30 or 33 HP.I know it doesn't list 37 hp anywhere

 

[Kernopelli]

37 sounds about right, the grey market machines are almost always numbered by PTO HP not engine HP....3110= rated 31 PTO HP which would take at LEAST 4-5 additional engine HP to achieve.

Well, They say that the 3110 is 37 engine HP. I have never seen any proof ( on a dyno) that my engine is 37 HP. My engine plate list ( I'm going off memory now cause I'm not around my tractor) 30 or 33 HP.I know it doesn't list 37 hp anywhere

 

[kenmac]

37 sounds about right, the grey market machines are almost always numbered by PTO HP not engine HP....3110= rated 31 PTO HP which would take at LEAST 4-5 additional engine HP to achieve.

Yes ,That's what I've heard, but like I stated. I've never seen proof of this. I would like to see the proof of this. .It just doesn't seem to have that much hp.Although, it may have 37 hp.I just have nothing to compare it to or know how 37 hp should behave power wise

 

[uofa314]

Got it torn down this morning. Thankfully, I didn't see any damage to the block at all. We are taking the head and block to the machine shop to get checked out. Also going to get the machine shop to replace the cylinder liners and main bearings while they have it there. I have rebuilt a couple of engines before, but I don't have much experience at this. I did find a service manual on ebay and ordered it so maybe that will help.

As far as the cause of the broken crank, I didn't see anything. When I pulled the head, I didn't see any signs of anything wrong. All three pistons and cylinder walls looked equally good. There was no signs of the head gasket leaking or any signs of fuel problems.

Also, the tractor was running fine until this happened. So, maybe the crank had some minor imperfection that caused the crank to fail due to high cycle fatigue. I'm a mechanical engineer at an old plant. Sometimes I see things like this, something breaks and can't find the cause. We send the broken parts to the lab. They can identify the failure mechanism. Sometimes it was caused by 40 years of vibrating back and forth.

But anyway, I'm about to order the parts. I'll take better pictures as I'm putting it back together. Will probably be next weekend.

 

[kenmac]

metal fatigue ??? did you try fredricks for the parts or just getting them from JD ?

 

[uofa314]

Kenmac, I ordered most of the parts from Hoye Tractor Parts and I ordered a used exhaust manifold and turbo from Worthington Ag Parts. I also got some of the studs and bolts for the manifold from John Deere.

 

[kenmac]

That's good. Reason I mentioned Fredricks is, I thought you could make the drive to Hartsel AL for less than shipping from Texas or, shipping from Fredricks for less . I Hope everything works out for you & you get your tractor running again soon

 

[uofa314]

Well, we got the engine back together and the dealer put the tractor back together. The engine is running fine and everything is good, except, now the hydraulics don't work. The frontend loader and lift don't do anything. The dealer says they checked everything and the pump is spinning, but isn't pumping. They said the only thing left to do is replace the hydraulic pump. It was working fine before the crank broke and we didn't do anything do the pump. We just took the timing cover off of the engine and the pump is attached to that cover. Is it possible for the pump to just stop working like that?