Hydraulic control valve

[Gary Sweat]

The kits that Ronald sells at Jinma Loader Valve sells do not use PB valves. Search in the Chinese and Yanmar tractor forums. You would need to keep the PB port plugged.

Thanks Kenny, I will give them a call next week and maybe they can tell me if there is another valve or another way to install the valve I have on my YM1900. For now I'm stuck.

 

[JohninCT]

Agree with what KennyD said...

I see your dilemma. When trying to find info on Yanmar hydraulic system, I found the link you mentioned that said to cut the steel pump line and tie the valve inlet (P) to the pump supply and the outlet (T) to the 3 pt hitch supply (google attaching koyker loader to yanmar). It says that if you have a valve that has power beyond to keep it plugged. While this may not be ideal, its probably your easiest solution to hook up the loader. I'm a little confused by your finding of the flow thru the valve. I would have expected with the PB port active, that the loader cylinder exhaust (and loader valve relief) would have been out the T port not the PB port. With PB port plugged, exhausting your cylinders and relief thru the 3 point hitch will create backpressure on the T port which may slow down the loader operation and increase the relief setpoint. This in my mind is the advantange of using separate PB and T ports.

This thread has a link that explains this in a little more detail just for info. I don't think that it will necessarily change how you are planning to hook your valve up.
http://www.tractorbynet.com/forums/hydraulics/116052-what-does-power-beyond-really.html

 

[Gary Sweat]

JohninCT - You are right in getting confused on what I wrote about the way the valve works. I got it wrong! The valve does use the PB port to pass the oil through when it is in neutral. There is a hole connecting the PB and Tank return ports so that the oil flow from the pump in the neutral position comes out into the PB port and then crosses over to the tank unless you use the PB sleeve and then that hole between the two ports is blocked and only PB port allows the pump pressure to go to the 3pt valve and keeps it away from the tank port so it won't over pressurize the port. The cylinder discharge goes to the tank port only and if the PB sleeve is inserted can't get to the PB port. My problem is that I don't have a return line anywhere on this tractor to connect the return oil coming from the cylinders and out the tank port back to the transmission which in this case is the oil reservoir. I'm hoping someone in the Yanmar forum can post a photo of how theirs is hooked up.

 

[David Devuono]

If you have a method of putting hydraulic oil in our transmission then you have a tank port. Take your tranny filler plug in and get a hose fitting that matches. Thats how its done on my kubota.

 

[Gary Sweat]

If you have a method of putting hydraulic oil in our transmission then you have a tank port. Take your tranny filler plug in and get a hose fitting that matches. Thats how its done on my kubota.

Thanks David - I'm in the process of making an extension tube for the filler since it's a plastic cap flat on top of the transmission and this tractor is from the 70's so I doubt anyone would have anything off the shelf that might work. I will put the return line in the side of the filler tube extension and make a longer dip stick for it. I saw a photo of one done by removing the fill cap but he lost the capability to check and fill without taking out the line. Cool idea but I want to keep the ability to check the oil from time to time. Seems that is the only way to route the return tank line on these model Yanmars.

 

[Gary Sweat]

I finally got the loader project finished today and just wanted to thank everyone for their help. I doubt I would have gotten it right without you guys. I really appreciate your patience, photos and information. The testing went well this evening and I will see how the tractor handles it tomorrow. That is the part that I am a little concerned about but we'll see. Either it works or I'll be looking for another tractor. I put some pics on the Yanmar forum. It's nothing special but I'm proud of it

 

[racerboy832]

I'm glad to see it all worked out. I'm on the Hunt for a similar joystick controller but I only need it for one double acting cylinder. (thumb). Can you point out any that will do the job. I've been looking at that baileynet place too. They seem to have some inexpensive joysticks but I don't want to order the wrong one. Thanks.

 

[Jay4200]

Gary -

Did you ever figure out what you first posted about? That is, the inability to blow air from the IN port (P) to any of the work ports when you pull the levers?

Here is my question: When I put air to the "P" port and move the joystick I do not get any air out of any port.

It was speculated that you needed more pressure to open a "load check valve". I am having the same issue but no-one has been able to offer a suggestion - my valve also has a "load check" feature. I also can get air flow to/from work to the OUT port (T) when moving levers (and vice versa), but can't get any airflow into the IN port when I activate the valves.

Thanks - JayC

 

[Jay4200]

I'm glad to see it all worked out. I'm on the Hunt for a similar joystick controller but I only need it for one double acting cylinder. (thumb). Can you point out any that will do the job. I've been looking at that baileynet place too. They seem to have some inexpensive joysticks but I don't want to order the wrong one. Thanks.

Why do you need a joystick for a single cylinder? Seems like an expensive waste of a spool.

JayC

 

[Gary Sweat]

Gary -

Did you ever figure out what you first posted about? That is, the inability to blow air from the IN port (P) to any of the work ports when you pull the levers?



It was speculated that you needed more pressure to open a "load check valve". I am having the same issue but no-one has been able to offer a suggestion - my valve also has a "load check" feature. I also can get air flow to/from work to the OUT port (T) when moving levers (and vice versa), but can't get any airflow into the IN port when I activate the valves.

Thanks - JayC

No I didn't and I never was able to blow air through it like I thought it should. JJ said it would likely have to overcome some resistance or check valve to get through to the valve ports and so I assumed it would work and it did. I noticed on my gauge that there is an initial few pounds on the gauge when I first start the tractor but it is only for a second. I have no idea how the internal workings are on the valve but I really like this one. Very smooth and easy to move the levers and you can move the loader and bucket a fraction of an inch if you want to. I put one of the plastic hose caps on the floor of the garage and lowered the bucket down until it just touched the cap without mashing it. Maybe I just got lucky.