HST Drifting normal?

   / HST Drifting normal? #1  

Anonymous Poster

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HI,

Got the new B2910 , today...and put three hours on the backhoe loader.

One thing that surprised me is that on a slight grade, when in gear and the parking brake NOT set, the tractor will not stay stopped, but will drift either back or forward, depending the whether the tractor is facing up or down.

I though I remembered a post where someone backed down a hill to his pond while cutting grass, took his foot off the directional pedal, and at his leasure pushed the forward directional to go back up. If I tried that with my tractor, I would have to be sure to get my foot on the other directional pedal pretty quick, or the brake.

I was expecting that the tractor would hold position if I was on a slope and took my foot off the hydrostatic directional pedal. But it does not. IF I am on a hill and want to stop, if I take my foot off the hydro pedal and don't push the brake pedal, I will drift down the hill. If I am facing up, I drift backwards. If I am facing down, I drift down forward.

I guess I was expecting to have the thing hold position, like an automatic car does on a hill...or at least like they used to with what we locally called a hill-hold feature.

On the level there is no creeping. If I am in one of the hst ranges and take my foot off the directional pedal, the tractor sit still and does not move. Again, this is on a level surface.

Do I need to talk to the dealer about his drifting on slopes? It does not take muich of a slope either. I would say just a few degrees and the thing wants to drift while the hydro is engaged and the parking brake is not set.

REALLY appreciate you help on this one. If it is normal to have this kind of drift that is fine, but if it is not, then I want to talk to the dealer about it pronto!

The tractor is new and I was running it at 1800 rpm. Perhaps things work differently at the rated 2500 rpm...but it will be another 46 hours before I see that engine speed!

Thanks...Bill
 
   / HST Drifting normal? #2  
I'd talk to the dealer. I see some drifting on steeper slopes but not that much. I wonder if you're seeing something like some of the FEL owners. Some of the owners can leave the FEL raised and it's still there the next day. Some FELs drop on their own within a short time. Supposedly either situation is normal. I'm thinking there's a range that the manufacturer believes is normal.

You might be outside that range. It'll be interesting to see the responses on this one. You might also consider calling Kubota in California. I've always found the folks there helpful.
 
   / HST Drifting normal? #4  
Bill
My 2910 works similar to yours. On a hill tractor will stop when I take my foot off pedal. It will hold that position for several seconds. Then I must use brake or HST pedal to hold position. Never leave you tractor on any incline without setting brake. It will roll after setting for a short time.
 
   / HST Drifting normal? #5  
Bill,

Congratulations again on the new tractor.

My B2910 behaves similarly to yours. I never really thought twice about it, just figured that's the way it was supposed to work.

It might depend on the implement that's on the back too! I don't remember if this happens any more or less wether the backhoe was on or not. It seems to me, though, that since the backhoe increases the total weight of the tractor by about 40%, that maybe it is more prone to drift on an incline with the added weight.

I'll have to experiment with this next time I've got the tractor out of its den.

~Rick
 
   / HST Drifting normal? #7  
"I guess I was expecting to have the thing hold position, like an automatic car does on a hill..."
To my knowledge and experience it would depend on the severity of the hill... not many automatic cars will hold position at idle on a steep hill... I believe it would be the same with a Hydro in a tractor... the higher the RPM the more hydralic pressure in the system... try upping your RPM's to hold posistion. Just a thought!
 
   / HST Drifting normal? #8  
I'd think this would be normal. We have a bunch of hydro-powered equipment at work (tractors and mowers) and they all drift on hills when you let up on the pedal. It would seem that is the nature of hydrostatic drives. I would recommend setting the parking break when ever you are leaving the tractor, or dropping a FEL or box blade. I would hate for someone or something to get hurt/damaged from a rolling tractor.
 
   / HST Drifting normal? #9  
Bill,

With HST you are really in neutral when not putting pressure on F/R pedal so some drifting is normal. Versus an auto trans in a vehicle is in gear when stopped. It has to do with the pressure plate/variable displacement setup in the HST transmission the more you press the more volume and pressure is sent to the drive system.

What you might find too as the unit gets some hours it will "seat" meaning have a larger neutral zone. All hydros do this even my older Cub Cadet LG tractor.

Carl
 
   / HST Drifting normal? #10  
My Ford 1210 and Kubota B7500 both drift a bit, and the Ford does it sometimes on even ground. Both drift very slowly on hills. They don't build up speed..................chim
 
 
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