Loader 2015HST
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RNeumann
Elite Member
I can offer a few basics- Does anything on the machine have hydraulic power? Will the loader lift anything? Does the steering feel heavy? Is the fluid filled to the proper level? Are the filters good? Did this happen suddenly or has it been a slow decline? Beyond that someone with more knowledge of HSTs and or this model will have to help.
Good luck and keep us posted. It's nice for all of use when we see the solution.
Good luck and keep us posted. It's nice for all of use when we see the solution.
DavesTractor
Elite Member
I'd review all that RNeumann mentioned first, as that was well thought out. Typically a clogged filter, low oil or similar.
Back in the day we saw a few HST charge pump failures on the 2015HST. Each time it was with a tractor that had been rototilling in poor soil and taking a beating at the PTO. The charge pump gear would crack. When this happens, it is pretty sudden and the tractor typically won't move at all or just barely. The charge pump can be installed without replacing the HST unit, but the tractor has to be split. Let's hope it is more simple that that.
Back in the day we saw a few HST charge pump failures on the 2015HST. Each time it was with a tractor that had been rototilling in poor soil and taking a beating at the PTO. The charge pump gear would crack. When this happens, it is pretty sudden and the tractor typically won't move at all or just barely. The charge pump can be installed without replacing the HST unit, but the tractor has to be split. Let's hope it is more simple that that.
Yes the hydraulics work can lift a load in the bucket steering is good fluid is level haven't checked filters yet thank you
DavesTractor
Elite Member
Before we jump to the charge pump, does the clutch have any free-play? It should push down about an inch before you feel any serious pressure. It's rare to have a bad clutch on an HST since they don't get used much, but we ought to check that first.
RNeumann
Elite Member
I'm a Newb to how the clutch and HST interact. Can you expand. All of my previous tractors have been shuttle and I have never depressed the clutch and tried to move with the HST.
DavesTractor
Elite Member
Different models use different approaches, with many HST tractors there is no clutch. But the 2015 had a conventional clutch. It was used when engaging or disengaging the PTO, used when changing ranges (although not really needed for that), and it was handy when starting in very cold weather as it allowed the engine to crank without the attendant effort to move cold hydraulic fluid in the trans. But that is a little off subject. A failed clutch on a HST equipped tractor will cause it not to move.
HST pumps are high pressure pumps, but they require some input pressure to the pump. Let's say that an HST pump produces 2500 psi, it might require 100 psi of inbound pressure. (I'm making these numbers up, pulling them out of the air for purposes of discussion). The lower pressure pump is the "charge" pump. It can be within the trans like on a 2015, or some tractors will use pressure off the engine mounted hydraulic pump, normally on the power-steering side of a duplex pump.
The charge pump on a 2015 is just a very simple gear pump, with a gear chasing around inside of a opening that is gear shaped but a little larger. As it spins it compresses fluid and does it's job. This gear is made out of very hard material. I have never seen a pump like this wear out, but I have seen the gear break into two or more pieces. Almost like it took an impact. And as mentioned, every time I have seen one break, it was with a 2015 with heavy rototiller usage.
HST pumps are high pressure pumps, but they require some input pressure to the pump. Let's say that an HST pump produces 2500 psi, it might require 100 psi of inbound pressure. (I'm making these numbers up, pulling them out of the air for purposes of discussion). The lower pressure pump is the "charge" pump. It can be within the trans like on a 2015, or some tractors will use pressure off the engine mounted hydraulic pump, normally on the power-steering side of a duplex pump.
The charge pump on a 2015 is just a very simple gear pump, with a gear chasing around inside of a opening that is gear shaped but a little larger. As it spins it compresses fluid and does it's job. This gear is made out of very hard material. I have never seen a pump like this wear out, but I have seen the gear break into two or more pieces. Almost like it took an impact. And as mentioned, every time I have seen one break, it was with a 2015 with heavy rototiller usage.
RNeumann
Elite Member
All good info. Does the clutch sit between the engine and the transmission like a standard vehicle or does it just service the PTO?
DavesTractor
Elite Member
Just like a manual trans tractor, clutch is bolted to the flywheel.
RNeumann
Elite Member
Thank you I learn something new everyday!
