FEL hydraulics overload question

[digger2]

I'm not a hydraulics tech,and i know alot of you guys are really up on this stuff,so here goes.I use my B7610 to haul firewood from the end of my property up to my house,loading my LA352 loader bucket about as full as i can get it,about 35 pcs. of average size firewood.Now i dont know how much this load weighs,but its relatively heavy.The 352 i beleive is rated to pick up i think 770 lbs. according to the kubota brochures.Question;I understand the loader will only pick up a certain amount of weight before some sort of relief
valve opens up so you dont start bending,breaking,and generally start screwing things up.But what if I raise the bucket empty to about waist high
and THEN handload the bucket full.Depending on what material you are loading into the bucket,it is possible to put more than the amount in the bucket than this thing is supposed to pick up.If i get to the point where i am over loading it,wil the bucket just decide to "drop",or will i start blowing seals
or what?Hope this question is understandable. Digger2

 

[MadReferee]

But what if I raise the bucket empty to about waist high
and THEN handload the bucket full.Depending on what material you are loading into the bucket,it is possible to put more than the amount in the bucket than this thing is supposed to pick up.If i get to the point where i am over loading it,wil the bucket just decide to "drop",or will i start blowing seals
or what?

Stuff could bend, seals could blow, among other things. Overloading is not a good idea.

If you want to carry more wood then build a 3pt carry-all platform. You will be able to carry probably 2-3 times what the bucket will.

 

[john_bud]

I'm not a hydraulics tech,and i know alot of you guys are really up on this stuff,so here goes.I use my B7610 to haul firewood from the end of my property up to my house,loading my LA352 loader bucket about as full as i can get it,about 35 pcs. of average size firewood.Now i dont know how much this load weighs,but its relatively heavy.The 352 i beleive is rated to pick up i think 770 lbs. according to the kubota brochures.Question;I understand the loader will only pick up a certain amount of weight before some sort of relief
valve opens up so you dont start bending,breaking,and generally start screwing things up.But what if I raise the bucket empty to about waist high
and THEN handload the bucket full.Depending on what material you are loading into the bucket,it is possible to put more than the amount in the bucket than this thing is supposed to pick up.If i get to the point where i am over loading it,wil the bucket just decide to "drop",or will i start blowing seals
or what?Hope this question is understandable. Digger2

Don't worry. The loader is designed to hold material much denser than wood. It won't just drop or blow out a seal due to static weight (well, unless you are piling it up really really really high). There may be a problem if you up the shock loading from banging into a wall, tree or similar. You could also get a shock load from bumpy ground bouncing the FEL & load. BUT, If you are running it fast enough to generate truely nasty shock loads the wood will bounce out of the bucket. So, don't worry.

I would however get a small trailer as that can haul more wood with fewer trips.

jb

Q: can you still raise the bucket when hand loaded ? If yes, then you are still not overloaded.

 

[ELMO67]

Stuff could bend, seals could blow, among other things. Overloading is not a good idea.

If you want to carry more wood then build a 3pt carry-all platform. You will be able to carry probably 2-3 times what the bucket will.

Yes, good advice, the weight will be where it needed more, and your tractor will be much more stable.

 

[Mahana79]

I wouldnt think that you could overload it with firewood. I mean you say you can fit 45 average pieces of wood right? and you loader has a rated cap. of 770#'s that comes out to each stick of wood weighing in at 17.1 pounds each. that is some darn heavy green oak there i dont think you would ever overload it with 45 pieces of firewood

 

[Timber]

Well that depends on How dense the wood is, How Green, if it is wet. The moor important thing is your Ballast. Overloading you bucket is more dangerous to your stability than your tractor. A little wet ground, a log you missed under the snow, and a over loaded tractor and you might have bigger problems than a blown seal

 

[chrisjbell]

I wouldn't worry about it. I load my tractor up with wood the same way you're talking about - bucket about waist high or a bit lower and as full as I can get it. I'm quite certain I'm not overloading it - I usually lift it up a bit more to carry it. It will handle a full bucket of rock and lift that up.

I have found loads it won't lift (and this is true on other, larger machines). That won't cause problems for you as the relief valves won't let it lift.

I did have a situation where I loaded a really big stump into a loader (not mine ;-)) that couldn't be lifted with the hydraulics. What I wound up doing was dragging it from a slope into the bucket with a chain. The bucket stayed up for a little while and slowly leaked down as I dragged the stump along. It worked out OK - I was trying to save some turf from damage at the spot I pulled the stump and dragging it was OK later on my journey.

I'm not sure I'd recommend doing that little trick, though ...

There were a couple of points made about counterbalancing (make sure you have enough weight in the rear) and not carrying your load too high. Good points - the closest I've come to tipping a tractor (so far) is with a load in the bucket up too high.

 

[m7040]

dont know how much this oak firewood weighs but from the looks of the front tires it is very heavy. Had to rev up the engine for the hydraulics to even lift it

 

[alchemysa]

I could be wrong but I doubt theres any 'one-way' valves in the system that try to hold the loader up under any load. (I think that would be a recipe for disaster as every time you bounced over mound with a full bucket you'd blow a hose.). So I would guess that the same relief valves that prevent you lifting a heavy load would open up and allow the loader to drop.

 

[MadReferee]

I could be wrong but I doubt theres any 'one-way' valves in the system that try to hold the loader up under any load. (I think that would be a recipe for disaster as every time you bounced over mound with a full bucket you'd blow a hose.). So I would guess that the same relief valves that prevent you lifting a heavy load would open up and allow the loader to drop.

Yes, there are no one way check valves that hold the loader up.

However, there is a load check valve and it's function is to activate and hold the load against gravity for that fraction of a second between the time the spool is activated and the time pressure builds up at the cylinder to hold the load. If the load check is was not there or is not working correctly you will get a very jerky motion of the loader every time the spool is activated.

 

[digger2]

As john bud has asked"can you raise the loader when fully loaded",Yes i can,and right after i posted this question i thought the same thing.Anyway,
i didnt want to risk messin something up.OK,thanks.
digger2

 

[Mahana79]

dont know how much this oak firewood weighs but from the looks of the front tires it is very heavy. Had to rev up the engine for the hydraulics to even lift it

i think that's a bit more than a bucket full

 

[john_bud]

As john bud has asked"can you raise the loader when fully loaded",Yes i can,and right after i posted this question i thought the same thing.Anyway,
i didnt want to risk messin something up.OK,thanks.
digger2

Well, there ya go! No problem and you probably picked up a few pointers on hydraulics.


That's a good time tractoring.

jb

 

[N80]

dont know how much this oak firewood weighs but from the looks of the front tires it is very heavy. Had to rev up the engine for the hydraulics to even lift it

I think I can see a little daylight under those rear wheels.

 

[m7040]

No the rear tires had good traction so no problem there. They are loaded and now yesterday I mounted a 2000 lbs ballast box on the three point. That is just so amazing how much that helps. Pushed over a large tree yesterday with no wheel spin at all.

 

[Mickey_Fx]

This discussion like most I've seen on FEL capacity is focused on the wrong thing. You should be looking and paying attension to the front tires/suspension and stability. My money is on rated load for your tractor if FEL is factory model, takes weight transfer and stabilty into consideration.

Have done all the math on my tractor and for every pound placed on the bucket, the front tires see an additional two pounds load on them, i.e. weight transfer. Tractor and setup will vary but you should know and pay attention to how much load the front end sees. How much extra capacity does your front tires have after carrying the weight of the tractor and FEL?

 

[California]

This discussion like most I've seen on FEL capacity is focused on the wrong thing. You should be looking and paying attension to the front tires/suspension and stability. ...
Have done all the math on my tractor and for every pound placed on the bucket, the front tires see an additional two pounds load

Great point. Especially with an aftermarket loader the tractor may not even have the oversize tires that would have accompanied a factory loader.

I've been thinking about another issue. The bypass is available when you are lifting, sending fluid to the cylinder. But after you return the lever the system is sealed with nowhere for excess pressure to escape.

I burst a hose when I stuck a loader fork in the ground and drove forward (clearing a down tree). In this case a $30, 20 year old hose was the first thing to go instead of bending anything so that was the best that could have happened. It seems to me it would be easy to create this sort of overload bouncing on rough ground with a heavy load.

Do any tractors have overload relief in each separate circuit?

 

[alchemysa]

I made a comment earlier in this thread that I thought the relief valves would take out the shock. However, upon looking at the parts diagram (because my tractor is too far away) it appears that the relief valve on the control unit may only serve to relieve excess pump pressure when attempting to lift a too heavy load. (As also does the relief valve at the pump itself). It appears on the surface then that theres nothing to take the shock off the loader. But then again, the parts diagram doesn't show the internal design of the control unit so perhaps the 'backpressure' from a bouncy loader is plumbed back to the relief valve somehow. It would seem sensible to me that some sort of pressure release is built into the loader/bucket circuit.