Broken Crank, What to do?

   / Broken Crank, What to do? #1  

uofa314

New member
Joined
Oct 12, 2012
Messages
11
Location
Tuscumbia, AL
Tractor
John Deere 1050
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.
 
   / Broken Crank, What to do? #2  
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
 
   / Broken Crank, What to do?
  • Thread Starter
#3  
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?

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   / Broken Crank, What to do?
  • Thread Starter
#4  
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?
 
   / Broken Crank, What to do? #5  
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
 
   / Broken Crank, What to do? #6  
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
 
   / Broken Crank, What to do? #7  
I am not trying to be negative, but I'll bet the block is trash.
 
   / Broken Crank, What to do? #8  
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
 
   / Broken Crank, What to do? #9  
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.
 
   / Broken Crank, What to do? #10  
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.
 
 
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