Can you identify a hydraulic control valve with a float position visually?

[mslisaj]

I have a six spool hydraulic control valve on my back hoe. It is supposed to have a float position on one of the spool valves and I believe I have identified that position because it has a longer "cap" at the bottom of the valve and at the end of the spool. I "believe" this longer cap houses a spring and is where the spool will be pushed into for the longer reach of the special valve to allow float. I am no hydraulic expert at all. I have read the hydraulic schematic for this valve and there appears to be an extra position or valve that will join the two ports together for the float and thus a "longer valve".

My question here to you men that know hydraulics, is my assumptions correct here? I realize this is kind of a generic question but I am looking for that generic answer. I can not push the valve (or control) into the float position and I am thinking there is something in that "cap" that is preventing it from moving into this position like a spring in the wrong place or something kind of simple - a mechanical block or debris. Again, I am just asking if my "theory" of operation is correct here and can I use that theory for a visual and diagnostic inspection.

Thanks for your help and response.

 

[oldnslo]

Yes your theory of the longer cap points towards a fourth position for that spool which could be float

 

[mslisaj]

Thank you "oldnslo" for taking your time to respond to my question here. This is kind of a baptism of fire as I'm learning this stuff as I go along. Years ago I had training and would rebuild automobile automatic transmissions. But this kind of hydraulics I have no real experience in. So I'm just learning it carefully as I go along.
Again thank you for pointing me in the right direction.

 

[newbury]

As always a picture with the parts in question pointed out and labeled would help greatly.

 

[s219]

Usually, valves with a longer can at the bottom do have float, and you’ll find the spring plunger with ball bearings down on that end, which are used to lock the valve into a detent. But normally unless there are other similar non-float valves to compare to, you can’t tell. There are also standard valves that don’t float but do have a detent that will look similar from the outside. So while we can make an educated guess, it’s hard to say for sure only looking at the outside.

 

[mslisaj]

Usually, valves with a longer can at the bottom do have float, and you値l find the spring plunger with ball bearings down on that end, which are used to lock the valve into a detent. But normally unless there are other similar non-float valves to compare to, you can稚 tell. There are also standard valves that don稚 float but do have a detent that will look similar from the outside. So while we can make an educated guess, it痴 hard to say for sure only looking at the outside.

Thank you gentlemen for taking your time to respond here. I'll pull the cover and get in there and look. Here is also a picture of the "hydraulic schematic" that clearly shows the "float" valve.

This is the basis for my question. I have a brand new machine with all indications of a float on the boom position. From the manual to the schematic. But my tractor "does not float". Will not go into the "detent" position or that extra bit of travel. I have been trying to determine if the valve was not set up for the float or it's defective. So a visual inspection of the longer cap will give me the clue. As I started this is a generic question and I realize there can be other possibilities but you men have launched me in the right direction to answer my basic question and I so appreciate that. When I get that cover off I'll take a picture and post it here. But I so appreciate your help.

Best regards,
Lisa

 

[mslisaj]

Well gentlemen you all have gone way beyond helpful to me here and I can't thank you enough. I finally had time to pull the inspection cover and all the end caps on the spool valves are exactly the same. The pictures here aren't the best but you can see in the two from slightly different angles that the caps across the valve are the same. Without tearing the valve apart I am going to make the assumption that this valve was not equipt with a "float" spool and detent assembly. I'm okay with this discovery as I explained I was more concerned that I may have something that is not operating correctly. While the manual and schematic discusses the "float" this perticular valve was apparently not set up with that option.

Again, I sincerely thank all of you for taking your time to share your expertise with me on this. Everyone made a huge contribution to helping me solve the mystery. Plus I learned more about my tractor and the hydraulic systems.

Best regards and Merry Christmas. :thumbsup: :drink:

Lisa

 

[/pine]

Just curious...what action on a backhoe would you want to set in 'float'?

 

[/pine]

BTW...the pictures show the working ports...not the bottom end caps?
edit...I guess you can see the caps through the hoses...disregard...

 

[tnjind]

I would think if you operated each valve then the one with float will move farther and you can feel it go into the detent.