226d leaking from power steering component

[Mooseman1616]

So I'm trying to post from my phone so sorry if the picture doesn't post, but today while working the tractor starting leaking oil from this little hole. From my research that's an indicator that I have a bad seal. Any help diagnosing or fixing this would be appreciated. I've already contacted hoye to get help but no definite answer or part to replace.

 

[Mooseman1616]

Here you can see what location I'm talking about and the little pin hole that it's leaking from. As I turn the wheel to the right it pulls a plunger out of the back of the box and when I turn the wheel left it pushes the plunger back in which then forces liquid out of the little hole.

 

[California]

Major edit - I just saw your second post with photos:

Turning the steering wheel pushes/pulls a small piston that controls flow into the main cylinder. Beyond the small piston there is a vent hole. After the small piston's o-ring, piston ring, gets old, hydraulic fluid gets pushed out of that small vent hole.

Here's the 'diaper' (photo) I put on mine temporarily when I bought the YM186D and it was spraying oil, before I got a replacement unit. But the units are rare. What you really need is to disassemble everything and replace that o-ring.

I had tried disassembling mine but I was afraid of distorting the aluminum casting. I couldn't find a way to hold it secure in my vise while unscrewing the big nut that holds it all together. So I stopped before damaging it. i was fortunate to locate another used unit.

That dealer-installed kit wasn't up to Yanmar quality standards. But it sure is handy to steer turning the center of the wheel with the palm of your hand when looking to the rear.

 

[bmaverick]

Member 'California' can give you a long history and info that these PS units LEAK due to the original design.

Now with that said, the Yanmar Cub Cadets have the newer generation PS. I've not taken measurements to see if the stroke is in the same realm to be an upgraded replacement.

Hoye stopped offering their PS units.

The Yanmar Tractor Owners Group has limited manuals for the PS units. Thru community member donations we have these.

 

[California]

Member 'California' can give you a long[winded] history and info that these PS units LEAK due to the original design.

The first of those PDF's, for YM186D, likely is applicable to YM226D also. With the only difference being a longer steering rod from the steering box and likely a longer hydraulic piston rod, going back to its fixed mount.

If anyone has opened one of these to replace the dribbly o-ring, I would like to hear how. As I noted I was afraid to apply enough force to break loose the big nut that is the first step to open it up. The aluminum casting looks like it would distort if clamped in a vise.

That little pinhole at the center of your photo is the culprit. It is intended to vent the air beyond the small control piston as that piston is moved in/out when you steer. But after oil gets past the control piston due to an aged o-ring, each steering maneuver squirts oil out of that hole.

At least your hole is aimed outward. On the smaller Yanmars it has to point up so the tire doesn't hit it in tight turns. There was oil on the side of the hood when I bought the YM186D. I put that 'diaper' on it until I had the replacement used steering unit.

 

[Mooseman1616]

So there are 4 bolts on the underside of the PS box there where it's leaking from, will popping that lower cover off not allow me to change out the o ring? I read through a long post on this from 2016 I think but didn't see any resolution come from that situation. Can I still drive the tractor? Maybe a dumb question but the fluid that is coming out is hydraulic fluid, correct? There isn't a separate reservoir for power steering fluid or something, right? So if I keep an eye on my fluid levels, I should be fine?

 

[Mooseman1616]

Power Steering Cylinder - Yanmar F FX and YM Series fits Hydraulics Cylinders

Power Steering Cylinder - Yanmar F, FX, and YM Series.

www.hoyetractor.com

So can I just buy this part from Hoye and replace the whole end unit?

Also, if going by the 186d manual, which numbered O ring am I looking to replace? Thanks again for any help you can send my way

 

[California]

Second diagram, O-ring #11 at the nose of the little control piston is what failed if that tiny air-bleed hole is squirting fluid. I don't remember now, but as I recall you need to disassemble everything to disengage the little control piston to get to the O-ring - at least on my YM186D unit that I attempted to repair. As I noted, I quit when I couldn't safely get enough force on the nut that has to come off to open it up.

Note the manual says don't disturb the factory calibration that assures neutral steering when the piston isn't pushed or pulled.

The steering fluid is plumbed from the same supply as the 3-point and loader. Trace the hoses to verify this. On mine 1,000 rpm minimum is needed before those other applications receive fluid - because the steering always has priority.

Hoye replied a while back that they sold out of their power steering kit. But I see they list it now. Its not the same as this Yanmar-labeled optional kit. And there are third-party kits for other tractors that might be adapted to use here.