Squirrel Tooth Alice
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- Chardon, Ohio
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- Massey Ferguson F-40, Kubota 7040, Kubota KX057-5
I've never seen an unloaded seal fail.
Leaving Implements Raised - Bad For Hydraulic System?
- Thread starter BackRoad
- Start date
- Views: 38132
How or why would it be bad for the hydraulics? The pump isn't running so there's less/no pressure other than the weight of the implement. There can't possibly be any more stress put on the cylinders than when lifting an implement or digging with the FEL. 10 times out of 9, hydraulic failures are due to lack of maintenance or operator error. The only true issue with lifted implements is the safety factor. I pull things with my chain on the draw bar sometimes, and the box blade is still on, too. Can't put it down with the chain connected to something, can I? Just don't put any of your body parts under anything lifted. I do much the same, leaving the engine idling for a quick off-tractor task, and shut it down if I'm going to be a while. If I've been digging stumps, I'll typically have one in the bucket, and the bucket tipped back and raised up so I can pick out roots and stuff, toss 'em in the bucket, and get it all done in one trip (obviously depending on the size of the stump and how many roots I pick up.)
4570Man
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I don’t drop the rear implement when I’m still working because I forgot to raise it and drag it. There’s plenty of times when the need arises to leave the FEL in the air. But I always lower everything when I’m done for the day.
bunchgrass
Gold Member
How can you know? You have to use it to know it has failed.
strantor
Platinum Member
Technically, every material is subject to plastic deformation under static stress. Imagine a gantry crane made of modeling clay; it might look fine before bed, but in the morning it's going to be bent over kissing the ground. Now imagine a gantry crane made of nylon. It would probably look just fine in the morning but wait a year and it will probably be sagging a few inches lower than it used to. Now an ordinary steel one. After 10 million years it would be sagging too (but it would be rusted to dust way before then). Hoses and seals subjected to constant pressure can "technically" be expected to experience more dimensional creep than those not subjected to them.
Practically though, static stress doesn't cause fatigue; movement (dynamic stress) does*. Practically, hoses and seals are going to fail from chemical breakdown of the rubber composites long before they have even a measurable amount of dimensional creep.
And, practically, exposed rods rust faster than those surrounded by hydraulic fluid, so for that reason (as well as safety) I retract everything as far as possible. I don't like that my FEL bucket bleeds down to expose 5" of rod. The mere fact of being located on the surface of planet earth is orders of magnitude more damaging to the system than being left unpowered under pressure.
* Google "static fatigue" for more information. Every practical study I can find on the topic, focuses on the failure of components subjected a combination of static and dynamic stresses, and the static component is only examined in the context that it contributes to dynamic fatigue.
Practically though, static stress doesn't cause fatigue; movement (dynamic stress) does*. Practically, hoses and seals are going to fail from chemical breakdown of the rubber composites long before they have even a measurable amount of dimensional creep.
And, practically, exposed rods rust faster than those surrounded by hydraulic fluid, so for that reason (as well as safety) I retract everything as far as possible. I don't like that my FEL bucket bleeds down to expose 5" of rod. The mere fact of being located on the surface of planet earth is orders of magnitude more damaging to the system than being left unpowered under pressure.
* Google "static fatigue" for more information. Every practical study I can find on the topic, focuses on the failure of components subjected a combination of static and dynamic stresses, and the static component is only examined in the context that it contributes to dynamic fatigue.
tonynz
New member
well I think that the load would be mostly on the piston seals and linkages, short term not much of an issue. One thing I have noticed with my MF 35 is that if you leave the 3pt arms up and turn off the engine, the arms will slowly lower over time and when you go to start up again, unless you remember to put the hydraulic lever in the down position, the starter motor has to also operate the pump, placing an unnecessary load on it- especially if you have an implement hitched up?
SylvainG
Platinum Member
That doesn't work for backhoe though. Can't have both swivel cylinders retracted and to have the dipper cylinder retracted, my backhoe bucket would be pointed at the sky. What's a guy to do in these cases?
strantor
Platinum Member
I don't have a backhoe, never had to consider it. But I think I would swing it all the way to the left when I park it. The right one can be the sacrificial lamb. No point in exposing them both to the elements.
oosik
Epic Contributor
The hydraulic pressure will slowly bleed off and the implements will lower to the ground because of that. That's what I thought would happen. After a month with my implements( FEL & 3-point) raised and having not dropped even an inch - I manually lowered them for safety's sake.
Creamer
Elite Member
There is nothing in the components that will be a problem. Seals are contained so that they can easily take the pressure created by various use which is significantly more than when stationary. The only issue I have see is that when cylinders are extended the rod can corrode or collect contamination which can get in the seals and cause leaks. Not a problem short term but it depends on how long they are left in that condition.
SylvainG
Platinum Member
Again, do backhoe cylinders made of special metal or last less longer than their FEL counterparts? Dipper and bucket cylinders are left exposed when 'at rest'.
rademamj1
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Backhoe cylinders are no different than any of the cylinders used in FEL or Grapples. You simply scale the cylinder for the amount of work required. Cylinder corrosion and seal breakdown on a parked backhoe is a concern, if it's been parked for many years exposed to the weather.
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rademamj1
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You cannot park any backhoe without extending some of the cylinders. The right and left stabilizer arms must be extended to park the backhoe.
SylvainG
Platinum Member
Hence why the fuss about the FEL cylinders being exposed if there is no other ways for backhoes and IF they last as long as FEL cylinders.
Snowlan
Silver Member
Not everyone lives in areas with the same risk factors. Near the ocean there is high salt content in the air, arid climates have high levels of fine grit in the air. Every time you retract the cylinder after being extended for periods of time in these conditions exposes the scraper rings to contaminants. Eventually they are worn and become less effective and the contaminants then attack the seals. Material that gets imbedded in the seal pack then runs up and down the rod leaving scrapes, bad enough and the seal can no longer contain the oil in the damaged section of rod.
The argument around the backhoe is ridiculous, I'm sorry. Just because we can't take all precautions with one device, we through all caution to the wind? Cylinder rod exposure is a factor, area of operation will dictate how much. In the marine industry you will be hard pressed to find vessel equipment designed for the exterior that doesn't have all cylinders retracted when in the parked position. Working in the offshore subsea construction industry our box section, knuckle boom cranes are why the ship is hired. It might need to be in the air for hour, days, weeks on end to suite the client's needs. If there is even an hour break in activity it gets parked.
Tools are like relationships, love them and they will love you back.
SylvainG
Platinum Member
Looks like you missed the uppercase IF I wrote, because IF backhoe cylinders last as long as FEL, why does it matter? Of course, if they last less, then it totally make sense.
