YT359C Sluggish Power steering

[Yander]

Nice tractor and yes that would be a problem for me too. Agree that you should not have to run high RPMs for basic steering function. Hope they take care of you guys, sounds like they might, keep us posted.

 

[rScotty]

Just got off the phone with Yanmar Tech Support.
They do acknowledge there is an issue and it is being addressed. They took my name and number and will get back if/when an engineering solution is available.

Please remember to update the group when Yanmar Tech Support fixes it. This sounds like a simple problem to address. I doubt that Yanmar designed it with the problem you are describing. It sounds like adjustment.

To answer that question about the JD310SE , and it's power steering.... most larger tractors have an independent hydraulic pump specifically for the power steering. So there is no way that steering can be influenced by other hydraulic systems. That's a nice feature and adds enough expense to beless common with utility and compact size machines.

I'm not sure how the newer Yanmars are plumbed, but know quite a bit about the older ones. Those had a shared hydraulic system with a single hydraulic pump. High pressure from the pump went first to a priority valve which distributed the flow. The priority valve was adjusted to insure that the power steering always had the necessary pressure regardless of RPM or accessory hydraulic use.

The degree of priority is simply adjustable on most priority valves. It just takes a wrench and screwdriver to change the percentage by which any system has priority over another. I wonder if the Yanmar's with a problem are simply misadjusted....perhaps when the loader was added. Some priority valves are also physically symmetrical - the old Yanmar ones were. So if the loader was added later that loader connecton to the priority valve is another source of error.

You could probably track this problem down yourself with a basic pressure gauge test kit and the appropriate hydraulic fittings. A hydraulic pressure testing kit is surprisingly inexpensive. It looks like $75 to $150 will buy a usable kit on amazon. Be sure you know which fittings your system uses.
Luck,
rScotty

 

[walnutman]

Please remember to update the group when Yanmar Tech Support fixes it. This sounds like a simple problem to address. I doubt that Yanmar designed it with the problem you are describing. It sounds like adjustment.

To answer that question about the JD310SE , and it's power steering.... most larger tractors have an independent hydraulic pump specifically for the power steering. So there is no way that steering can be influenced by other hydraulic systems. That's a nice feature and adds enough expense to beless common with utility and compact size machines.

I'm not sure how the newer Yanmars are plumbed, but know quite a bit about the older ones. Those had a shared hydraulic system with a single hydraulic pump. High pressure from the pump went first to a priority valve which distributed the flow. The priority valve was adjusted to insure that the power steering always had the necessary pressure regardless of RPM or accessory hydraulic use.

The degree of priority is simply adjustable on most priority valves. It just takes a wrench and screwdriver to change the percentage by which any system has priority over another. I wonder if the Yanmar's with a problem are simply misadjusted....perhaps when the loader was added. Some priority valves are also physically symmetrical - the old Yanmar ones were. So if the loader was added later that loader connecton to the priority valve is another source of error.

You could probably track this problem down yourself with a basic pressure gauge test kit and the appropriate hydraulic fittings. A hydraulic pressure testing kit is surprisingly inexpensive. It looks like $75 to $150 will buy a usable kit on amazon. Be sure you know which fittings your system uses.
Luck,
rScotty

Unfortunately the tractor is under a full 10 year warranty. I don't dare mess with the bypass settings.

 

[chevyman29]

Hey guys did anyone ever get a resolution in this ?

I've got a new yt359 open station, over all it's a pretty nice tractor but this steering issue is ridiculous.
On mine it doesn't really matter if it's revved up or not with a bucket of dirt it just doesn't want to turn.
No way all of them are like this.
Mine sounds like a relief valve is by passing. But I don't know a lot about how it works.
I do know I've owned 4 JD and 1 Kubota and none had any trouble steering at any rpm as long as the tires wasn't flat.

That being said the dealer is coming to get mine next week to look at it . We'll see.

 

[walnutman]

Unless there is a mistake in the online specs, it shows the 359 to have about 5 lpm hyd flow LESS than the 347.

https://www.yanmar.com/eu/agri/wp-content/uploads/sites/12/2022/10/YT3-ENGLISH-7271-LR-SPREAD-V0517.pdf

Researching more, I found this...

Power​

No surprises here: the YT347’s smaller engine limits power to the PTO to 39.5 hp, while the YT359 can deliver up to 52 hp. However, when it comes to hydraulic flow rates, the 347 exceeds the 359. The smaller tractor can move up to 10.1 gpm (38.3 l/min) for the PTO and 5.7 gpm (21.7 l/min) for the power steering. The 359 only pumps 9.4 gpm (35.5 l/min) through the PTO hydraulics and 5.3 gpm (20.1 l/min) through the power steering system.

Yanmar Tractors: YT347 vs. YT359 | Shank's Lawn Blog

 

[walnutman]

Hey guys did anyone ever get a resolution in this ?

I've got a new yt359 open station, over all it's a pretty nice tractor but this steering issue is ridiculous.
On mine it doesn't really matter if it's revved up or not with a bucket of dirt it just doesn't want to turn.
No way all of them are like this.
Mine sounds like a relief valve is by passing. But I don't know a lot about how it works.
I do know I've owned 4 JD and 1 Kubota and none had any trouble steering at any rpm as long as the tires wasn't flat.

That being said the dealer is coming to get mine next week to look at it . We'll see.

It will turn if you begin moving the tractor but to me that is unacceptable.

 

[walnutman]

This is true hydraulic steering. Paschal's Law aside, there is a reason that hydraulic tests are not performed at idle. Set the hand throttle at around 2k rpm and is should improve. Remember, if you are lifting a heavy load, it is true hydraulic steering and may be going over the relief built within the orbitrol (steering) valve. If this should happen, the slightest of movement should allow you to turn. Best of luck, let us know if this works.

This is the only answer at this point. I think it's a design flaw and judging from the responses from Yanmar, they don't seem to want to admit it. I called Yanmar tech support. They put me on a "list".
I love this tractor. When I do have a full bucket and the steering won't budge, I simply begin moving the machine and the steering works.. Think about it, turning the wheels when not moving doesn't do much for the work you are doing.
Yes there are times where you want the machine to start going a different direction from a standstill. This is where the problem lies.

 

[rScotty]

The degree of priority is simply adjustable on most priority valves. It just takes a wrench and screwdriver to change the percentage by which any system has priority over another. I wonder if the Yanmar's with a problem are simply misadjusted....perhaps when the loader was added. Some priority valves are also physically symmetrical - the old Yanmar ones were. So if the loader was added later that loader connecton to the priority valve is another source of error.

You could probably track this problem down yourself with a basic pressure gauge test kit and the appropriate hydraulic fittings. A hydraulic pressure testing kit is surprisingly inexpensive. It looks like $75 to $150 will buy a usable kit on amazon. Be sure you know which fittings your system uses.
Luck,
rScotty

Unfortunately the tractor is under a full 10 year warranty. I don't dare mess with the bypass settings.

Maybe - probably - it's just me, but I don't see the sense in not checking it yourself. Maybe an adjustment is the problem and maybe not, but testing the pressures and adjusting a priority or relief valve is a simple process. Doing that is no more complicated than any other routine maintenance and routine maintenance doesn't affect the warranty.

Having PS that works properly seems better than having an unresponsive 10 year warranty.

 

[walnutman]

Maybe - probably - it's just me, but I don't see the sense in not checking it yourself. Maybe an adjustment is the problem and maybe not, but testing the pressures and adjusting a priority or relief valve is a simple process. Doing that is no more complicated than any other routine maintenance and routine maintenance doesn't affect the warranty.

Having PS that works properly seems better than having an unresponsive 10 year warranty.

Maybe it's set to bypass just before the steering link bends or breaks or the cylinder seal blows. If they can design that amazing transmission, they sure as heck can design power steering that works in these conditions. The issue is they are ignoring it and not acknowledging.

 

[rScotty]

Maybe it's set to bypass just before the steering link bends or breaks or the cylinder seal blows. If they can design that amazing transmission, they sure as heck can design power steering that works in these conditions. The issue is they are ignoring it and not acknowledging.

I'd assume that Yanmar got the design right. Chances are that someone set it up wrong when assembling it or adding loader or remotes. My guess is that Yanmar knows that too & is why they are ignoring it.

But does it matter? It's easy to check the hydraulics with a gauge and see if the pressures are correct. That's the first step.
If you do that, you might want to leave gauges inline where you can glance at them while the tractor is working. That's what I do on mine. Surprising what can be learned that way.

rScotty