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loader hydraulics

deeremd Join Date: Jul 2003 Posts: 18 maryland

2003-05-19          55098

I used my new 790 w/419 loader last night to help hang lights in my garage. Over the course of about 20 minutes, I noticed that the loader bled-down about 3 or 4 inches from max height. Anybody know if this is normal? There was basically no weight in the bucket -- I was just using the bucket to hold-up one end of an 8 foot long shop light. Is there anything I can do to prevent this bleed-down when I need the loader to stay up in one position?


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loader hydraulics

DRankin Join Date: Jan 2000 Posts: 5116 Northern Nevada   Pics

2003-05-19          55100

Deere considers that amount of leak-down normal. In fact they do not consider it a problem and will not fix it under warranty until the leakage exceeds a rate that equals several feet of bucket motion in an hour.

The FEL on my 4100 leaks about as much as you describe, but the three point hitch will stay up for days with several hundred pounds on it.

Conversely, the FEL on my BX does not leak-down at all but I lose a couple inches overnight on the three point.

Go figure.

I know of nothing you can do to slow or stop the leak-down. I have noticed that it is almost nonexistent in colder weather.

Based on that observation I would say that the viscosity of the hydraulic oil plays a part. But I don't think you can choose a different viscosity in tractor hydraulic fluids like you can in engine oils. ....

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loader hydraulics

TomG Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley

2003-05-19          55109

My loader with its mystery British valve assembly doesn't leak-down anywhere that much and it's 10 - 15 years old.

I believe what MarkH says about JD leaders and warranty is correct. However, leak-down isn't enviable it just depends on the type of valves and cylinders used. It's tempting to say a higher quality of valve wouldn't leak-down, but for all I know a valve that leaks a bit may have some advantage such as longer life. Qualify can be a bit tricky to judge. I suppose the JD idea is that loaders aren't intended to stay in fixed positions for long periods during operation so some leak down can be tolerated.

If the leak-leak down is in the valve rather than the cylinders and the cylinders lines use quick-connects, then disconnected the lift lines from the valve should stop the leak-down. I'm not sure that's a very practical solution though. There are some safety considerations if a person is climbing into a raised bucket to work, especially if the tractor is running.
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loader hydraulics

deeremd Join Date: Jul 2003 Posts: 18 maryland

2003-05-19          55123

For the record, I was using the tractor just to hold one end of the light while I was up on a ladder screwing the other end into the ceiling. I wasn't in the bucket...honest! Also, the engine was turned-off so I wouldn't gas myself in the garage.

I also noticed that the loader bleeds down when I'm out cutting the grass, and I have to tweak it up again. So, the bleeding does not seem to have anything to do with whether the engine is running or not... ....

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loader hydraulics

DRankin Join Date: Jan 2000 Posts: 5116 Northern Nevada   Pics

2003-05-19          55127

Yup, mine (and from what I can gather most JD compacts) leaks down with the engine running too. ....

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loader hydraulics

plots1 Join Date: Jul 2003 Posts: 563 mo   Pics

2003-05-19          55134

MY 790 WITH 419 LOADER WILL DROP A COUPLE OF INCHES ALSO OVER NIGHT , SO AS MARK SAID IT MUST BE A NORMAL THING FOR THE COMPACTS. DON'T SEEM TO AFFECT THE WAY IT WORKS.I NOTICED IT WITHIN THE FIRST 10 HOURS I GOT IT .IT WILL ONLY GO DOWN A LITTLE THAN SEEMS TO HOLD THERE.MINE WILL NOT GO ALL THE WAY TO GROUND IF LEFT UP ABOUT 6 INCHES OVERNIGHT.I WONDER IF IT'S MENT TO BE THAT WAY TO RELIEVE SOME PRESSURE OFF OF VALVE? ....

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loader hydraulics

TomG Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley

2003-05-20          55147

My engine running thing was just some a mini-safety reminder and not intended to suggest that anybody is actually riding in a bucket. Position control 3ph's that leak down will cycle up and down when the engine is running but the engine shouldn't make any difference to loader leak-down.

Interesting comment about the loader leak-down stopping at 6" off the ground. When loader arms go below horizontal the bucket comes back toward the tractor. Maybe that reduces the pressure enough to stop further leak-down. Cylinders with cushioned stops might be another explanation but I doubt they'd be used for lift cylinders. A common application for them is backhoe swing cylinders.
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