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John Deere 850 head gasket

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mobilus
Join Date: Jul 2007
Posts: 171 Clay County, TX
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2007-11-08          147977

Does anyone know the torque value for the head bolts on a John Deere 850 3-cylinder diesel?

Any info is appreciated!


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John Deere 850 head gasket

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candoarms
Join Date: Mar 2007
Posts: 1932 North Dakota
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2007-11-08          148014

Mobilus,

I'll contact my good friend, Mick, for you tomorrow morning. He may have a manual for the 850 in his shop.

Mick has been repairing John Deere tractors for more than 40 years.


Hang in there. I'll get back to you as soon as possible.

Joel ....

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John Deere 850 head gasket

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mobilus
Join Date: Jul 2007
Posts: 171 Clay County, TX
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2007-11-08          148019

Thanks, Joel. I really appreciate your help.

I pulled the head off tonight. The middle cylinder has some pretty bad deposits (carbon, I guess) on the piston and around the valves. Not sure if that is a result of the overheating or not. I'm taking the head in to town tomorrow and dropping it off at a machine shop. I want to make sure that the head isn't cracked. The engine block deck looks good, but I'll probably go ahead and pull the studs that didn't come out. Then I can check for flatness.

Oh, I almost screwed up big time. I grabbed the push rods after the head was out, but didn't count to make sure I had all six. One had fallen down to where I didn't see it. And, when I bumped the starter, I found it...so I backed off on the crank and pulled the now bent push rod out. Weird part is, it had been rubbing something already, and had a pretty good divet, so I would have changed that one anyway.

I wish my digital camera wasn't messed up. It's about five years old and has had a rough life. I would borrow the wife's, but she keeps it at work (realtor). I might buy a cheap one.

Anyway, thanks again.
Mark ....

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John Deere 850 head gasket

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candoarms
Join Date: Mar 2007
Posts: 1932 North Dakota
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2007-11-08          148020

Mobilus,

Just out of curiosity, how many hours are showing on the meter?

The deposits you mentioned probably came from a slight leak in the head gasket, especially since it was only on that one piston. Either that, or you had one valve that wasn't closing fully.

The push rod that you bent.......did it show signs of wear at the end that goes through the head (top) --- or near the base, where it contacts the cam shaft?

And lastly, what was the reason for tearing this engine down? Did you notice something that caused alarm?

I'll get back to you one way or the other. Mick has a shop full of manuals. I'd be surprised if he didn't have one for the 850, but if not I'll be sure to let you know right away.

Joel ....

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John Deere 850 head gasket

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mobilus
Join Date: Jul 2007
Posts: 171 Clay County, TX
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2007-11-11          148116

Head's off! Not good either, as the middle cylinder is a mess. It's obvious that the coolant has been leaking into that cylinder for a long time. Check out my pictures 16-18. I put kerosene in the cylinders and didn't get any leaking by the piston rings. Now I need to take the rest of the stuff off the casting. Hopefully, we'll find another head. The crack is in the shiny spot between the exhaust valve and the injector port. Doesn't look like it'd cause all this trouble, does it?

Joel, the push rod was damaged about a third of the way from the top, and it kind of looks like it was already bent a little.

....

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John Deere 850 head gasket

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candoarms
Join Date: Mar 2007
Posts: 1932 North Dakota
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2007-11-12          148133

Mobilus,

Mick called me back this morning. He doesn't have a manual for the 850. The tractors in this area are generally much bigger than the 850.

Sorry to hear about the cracked head.

Joel

....

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John Deere 850 head gasket

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mobilus
Join Date: Jul 2007
Posts: 171 Clay County, TX
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2007-11-12          148162

Joel,

The owner is contacting some wrecking yards in Oklahoma. The local JD dealer's parts guy told me that they could get a new head, complete, for $950. That's why the owner is looking for a good used one.

Oh, the tractor only has 1470 hours on it.

Take care, friend.

Mark ....

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John Deere 850 head gasket

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candoarms
Join Date: Mar 2007
Posts: 1932 North Dakota
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2007-11-12          148164

Mark,

There are many tractor graveyards around the country. If you need any help finding a used head, give me a shout. I'll see what I can drum up for you.

Joel ....

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John Deere 850 head gasket

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mobilus
Join Date: Jul 2007
Posts: 171 Clay County, TX
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2007-11-12          148165

Thanks, Joel. I'll wait until I hear from the owner...if she doesn't find one, I'll call on you.

I'm constantly amazed at the lack of regular maintenance on some folks' tractors, equipment and vehicles. Before she gets the tractor back, it'll get new fluids, filters, etc. Oh, and a good pressure-washing! When I was doing some plumbing projects a couple of years ago, I ran hot water lines to spigots on either side of the house. It comes in handy when blasting away caked-on grime like this tractor has. Doesn't make the wife too happy, so maybe I'll put a water heater in my next shop.

Have a tractor day (any day with a tractor is a good day).
Mark ....

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