850 Hydraulics Quit

Jeff Wenner · Mar 13, 2015

I use my 850 for snow removal during the winter. A
couple weeks ago it was below 0 and I went out,
plowed some snow with the 3 point blade and
everything worked great. Next night got some more
snow, went out and started her up and nothing. Lift
arms didn't even budge. I thought maybe some
moisture had frozen somewhere in the system causing
the problem. Been up in the 50's this week so things
should be warmed up, still nothing. Any suggestions
where to start troubleshooting this problem?

souNdguy · Mar 13, 2015

Assuming you have oil, open the plug on the top of the pump and crank over.. see if it is making flow. Post back

shaun wallace · Mar 13, 2015

One of 2 things could have happened if oil doesn't run out bleeder plug. The bolts on back of camshaft or splines in pump gear sheared. Later only takes pump removal to fix other requires split.

Kurt-NEPA · Mar 14, 2015

When I hear a hydraulic system ran just fine, but when it sat overnight it would no longer work at all, I start thinking, the pump lost its prime.

While it could be lots of other things, I would check that first. If you loosen the pump primer plug, crank the engine, and get oil with bubbles let it crank a bit until the bubbles stop, then tighten the plug. Or if you want to get more involved get some clear tubing and plumb it from the bleeder plug hole to the sump fill opening. Start the tractor. You should see a continuous flow of oil. If you see bubbles, you most likely blew the pump's wobble shaft seal. If you see nothing, it could be the pump gear is stripped as was suggested previously.

The other thoughts that I had is that could have a stuck unloader valve, linkage problems or a broken cam follower pin. But I would check that pump.

Jeff Wenner · Mar 14, 2015

Forgot to mention, it's the earlier vane pump.

Kurt-NEPA · Mar 14, 2015

That does complicate things a bit. Note many hundred series tractors have vane pumps.

The easy way to prime the pump is to park the tractor nose down in a ditch. Let is run a bit and see if you get your hydraulics back.

Another method is to use a rubber tipped air gun and blow some low pressure air into the dip stick hole while the tractor is running. That may push some oil up to the pump and get it working.

Keep us posted.

850 Hydraulics Quit

Jeff Wenner

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souNdguy

Well-known Member

shaun wallace

Well-known Member

Kurt-NEPA

Member

Jeff Wenner

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Kurt-NEPA

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