JD850 with JD80 front end loader--Hydraulics issue, bucket strains to dump and has no strength

[Niji]

Hey Folks,

I have a JD 850 4x4 tractor with the JD 80 loader and recently my bucket began really straining to dump causing the hydraulic pump to whine big time. Closing the bucket works fine. Also, it has no strength when opening, so while it will hold up to carry a barrel of water or some firewood for example, it will not lift the tractor's front end off the ground (to change a front tire, for example) by opening the bucket as it usually does. About two years ago I went through and rebuilt all four cyliners on the loader. Interesting fact there--the small cyliners on the bucket had JD configured parts numbers on them, but JD had no record of them. I had to take those cylynders to a shop so that the parts could be matched up and they did a great job with that and the cyliners bench tested fine and have not leaked or given any issues since.

I suspect that a hose might be collapsing? Some of the hoses are original on those small cylinders. Not sure if there is an easy way to test for that? Perhaps taking the ends loose and squirting into a bucket to see if full flow is present?

And I am not well versed in hydraulic systems, so could there be a particlular valve failing that would affect only the dump function and not the big cylinders or the closing of the bucket?

Any help much appreciated. Oh, and I guess I ought to double check the quick connects where the loader attaches to the tractor hydraulics just to be sure there's not some half connected hose there just in case it is something stupid simple like that.

Any insights much appreicated!

 

[WinterDeere]

If a system is operating properly, there should be no opportunity for a hose to collapse, as even those on the return side of any circuit are under slight positive pressure. I can't remember the reservoir venting situation on the 850, but assuming it is vented in some way, there is no way for the hydraulic pump to draw pressure on any return hose below atmospheric pressure.

Are you sure your SCV linkage hasn't gotten so sloppy that it's failing to fully-actuate the valve? It seems 90%+ of all older tractor hydrualic control problems eventually trace back to the linkage.

Filters can clog over time, so always worth checking if it's been awhile, and nothing else is obvious. Same with reservoir vents, find and ensure it's not clogged.

 

[zzvyb6]

Switch the couplings so that curl and lift are swapped. Then see if lifting the loader arms is a problem and curl is now ok. That should isolate the problem.
BTW: I found that it was an easy conversion from the 80 loader bucket pin mounts to the JD QA system. Even the bucket lever indicator swapped over. I bought the QA bucket (but the brackets could have been swapped out), forks, snow plow, a grapple and a tree puller that really changed life around here !

 

[Niji]

Okay--thanks for these initial thoughts, guys. I will try to devote some time to looking into it in the next day or two. zzvyb6 -- nice on the QA mounts! I never take the bucket off as I only have three-point-hitch equipment otherwise--including the round bale spear--so I doubt I'll go the extra mile but that is a nice deal. And do I remember seeing a photo of you hauling a haywagon with a Corvette years ago? I am thinking that was you....

I'll report in when I know more. Thanks!

 

[careyo63]

The QM are nice! Many Hrs. on this 5103

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[RustyA]

Is it possible one of the hard lines on loader got smashed partially shut restricting flow? If not try swapping lines and see if restriction follows the line?

 

[zzvyb6]

Okay--thanks for these initial thoughts, guys. I will try to devote some time to looking into it in the next day or two. zzvyb6 -- nice on the QA mounts! I never take the bucket off as I only have three-point-hitch equipment otherwise--including the round bale spear--so I doubt I'll go the extra mile but that is a nice deal. And do I remember seeing a photo of you hauling a haywagon with a Corvette years ago? I am thinking that was you....

I'll report in when I know more. Thanks!

Yep. That was me in my Y2K 'vette. Standard Draw-Tite bolt-on hitch was readily available. I was being passed on I-96 by a blond in a MB-250 convertible, (top down, a bit too close on the side for my comfort), I sped up to over 100 mph to keep up with her (road was 5 lanes wide btw). (which the CAN-Buss nicely saved for me), and she gave up. I'll bet she's still spitting seeds and chaff out of her heater vents. I was advised that the trans may overheat and should give focus on the display for Transmission Temperature. It was 190 deg F idling in my driveway prepping the trailer, and 145 deg F running on the highway at 70 mpg. And: 21 mpg hauling 100 bales at speed with the trailer loaded. It increased on future trips after i aired up the 4 trailer tires to 45 psi from 35.

I ordered the car via GM Fleet Operations as an employee. It was to model specs that a local dealer begged me to get a car from him (slightly [and gently of course] used). He was limited to 2, and I could order 5 ( ????). Most of his local trade-ins are abused (tires & paint). Got it for the 7500 mile 40% discount, and I put those miles on it ! Dealer happy. Me very happy $. Went with Tahoes after that for all the relatives and my hay delivery and weekend fishing boat businesses. 'Vettes absolutely not suited for launching or retrieving boats at a ramp ...

And THAT, is the rest of the story!

 

[Niji]

I thought that was you with the Vette. I was telling about that with a friend when I was up in Maine working horses last weekend--he has all kinds of equipment and a Vette so it reminded me of that photo you posted years ago. Funny coinsidence to see you on this thread today! Thanks for the photo, again!

 

[ponytug]

@zzvyb6 that is an amazing photo and an amazing story to go with it. I'm impressed at how well balanced the trailer and 'vette are loaded.

All the best,

Peter

 

[zzvyb6]

@zzvyb6 that is an amazing photo and an amazing story to go with it. I'm impressed at how well balanced the trailer and 'vette are loaded.

All the best,

Peter

The 4 place snowmobile trailer with that hay bundle and axle positions gave me about 60 lbs of tongue load. That'a about 1/2 a tank of gas. Plenty of tire reserve capacity for stopping, and nowhere near the bump stops. Rear wire loom was already set up for trailer lights and brakes.