79 JD 850 worth fixing?

[Bob88]

I have a 1979 John Deere 850 and the engine needs rebuilt now. It was working alright for me before hand not great but did what I need. Here is the carnage see pictures below. Would you think it’s worth saving or just get what I can a move on?

So far I’m thinking that parts are getting harder to find and that I may as well get what I can from it and move on. But would like to here some opinions other than my own arguments.

 

[JimRB]

Some places with sell you a crank for $500-600. Rebuild kit with new pistons and standard rod bearings for $500. I would assume the tractor is not worth much not running. No oil? Failed oil pump?

 

[Agvg]

How much is the cost to get the crank machined? Suppose you can get overdim bearings, did the bearings rotate and did damage to block or rods?

 

[Kernopelli]

Looking at prices for Yanmar 3T80-J sleeves, pistons, rings, bearings, gaskets and crank machining, it would run about $1000. Depending on what it needs, you could get away for less or maybe a few hundred more if you wanted to do the heads too. Hard to believe it wouldn't be worth doing if you can do the wrench turning.

 

[Bob88]

Looking at prices for Yanmar 3T80-J sleeves, pistons, rings, bearings, gaskets and crank machining, it would run about $1000. Depending on what it needs, you could get away for less or maybe a few hundred more if you wanted to do the heads too. Hard to believe it wouldn't be worth doing if you can do the wrench turning.

I can do the work I need a few tools that I don’t have but nothing major I found a full rebuild kit for 800 and a crank for 500 so 1300 probably another 200 for tools and other misc items 1500 or so but I’ve already found that parts are getting harder to find and it wasn’t working great for me in the first place. Its a jack of all trades master of none. I know it’s needs a full rebuild because there is hardly and force needed to turn engine by hand with a ratchet on crank pulley.

I’m not sure if the crank can be turned or not that may be cheaper if it can.

I already have a bit invested in this tractor so I hate to condemn it but I also am getting tired of throwing money at it. It will need tires and probably brakes might as well do a clutch while the engine is out and that’s where cost creeps up. I also know it has a spool valve that isn’t working right haven’t got into that yet.

I’m not sure what caused the bearing to go out right now so I also have that problem to figure out as well.

 

[Bob88]

It might be a good time to upgrade, but then you're faced with the emissions junk on the new stuff. Your info says "Attachments: Blade snowblower belly mower" so you'll also be faced with getting something to deal with the grass and snow if you sell the 850. Can you get by with a smaller machine or something in the used department like an 855?

I have rear blade, front mounted snow blower, and belly mower. It would be nice to have those still but, I can get a lawn mower and I have a four wheeler with a plow for snow. The blade was nice for maintaining my driveway but I have access to a skid loader for that and driveway maintenance is only a few times a year. If I got another tractor 4wd would be a must and hydrostatic would be preferred so that puts it out of what I would spend for something else.

 

[Zebrafive]

What could you sell it for as basket case?
What would it cost to fix?
What would it be worth fixed?
How much would a replacement cost?

Answer these questions and then you can decide which way to go.

 

[shooterdon]

My JD855 was nickel and diming me. I decided to trade it this year. But I was not able or willing to "wrench on it". The dealer gave my $7000 for it with the 30 year old attachments (brush hog, tiller, MMM)

If you have the skill and the time, putting $1500 is not a terrible idea. You should be able to make a bit of money on it if you decide to trade and a running tractor is worth a lot more.

 

[TimberHole]

I have done a couple of JD 950’s with the 3T90J. First was in frame and I think I spent about $1,300 including the head work. Split the second tractor and did a complete overhaul. I spent something close to 3K total. You might be able to turn the crank. I think you can .030 but don’t hold me to that. They are cool old tractors so I would never discourage anyone from repairing but the costs do add up. I also had to make some tooling to press the front and rear bearings in and out. Fun project though.

 

[thepumpguysc]

I know people who would sand the crank down w/ emory cloth, throw a set of brgs in it & call it good enough..
BTW> check that oil pump or get a new one..