roger_scotty
Gold Member
"I question your second negative. If I buy a Prince SCV valve for example, the only difference in the three configurations of hydraulics are the outlet section of the SCV."
Keith, you are right to question the second negative. We are both correct up to a point. It is true that some SCVs (selective control valves) do have the ability to be used with an open or closed system pump depending on the parts installed. As you say, these are usually - but not always - the type of SCVs that are made in sections. Also, sometimes the SCV does have a plug that can be exchanged to change its application. My comment was meant to warn you that you cannot count on this convertability in most SCVs.....particularly the ones commonly used as two spool loader control valves. That optional ability makes for a costlier valve than most loader manufacturers want to provide. I assume that if you have one with both abilities then you will know it.
"I am guessing that the nipple on the end plug blocks the open center through the work sections from reaching the outlet. Perhaps simply removing the material will change the configuration?"
Well... MAYBE....above..
"I do not understand when you say the attachments are the same, and it is the output connections of the tractor that are changed. Are there some tricks I do not know about? I would think it is strictly dependent on the attachment valve."
Whoa! I think we need to back up a step. Maybe we took too big of a step right at the first. It is the HYDRAULIC PUMP in the tractor that determines whether you have an open or closed hydraulic system in the first place. You do not have a choice as to what kind of valve you want to use. It is determined by the pump in the tractor. Period. Almost all older compacts tractors as well as all PTO or crankshaft nose-driven hydraulic pumps are open center.
An open center pump has constant recirculating flow and develops pressure when the flow is restricted. Conversely, a closed center pump maintains a constant pressure and develops more flow when the pressure drops. They are worlds apart.
A better way to interpret my answer would be: Regardless of which pump the tractor has, the job of the tractor is simply to provide hydraulic flow to the implement.
Regarding the weight of the Bradco. I don't know the 7LD model, but you might want to check. The smallest Bradco I know if is the 3375 series and it weighs 1100#. Bradcos tend to run about 50% heavier than Kelly, Bush Hog, or GB. for the same lift and depth. And those lighter hoes are more than adequately strong.
Keith, you are right to question the second negative. We are both correct up to a point. It is true that some SCVs (selective control valves) do have the ability to be used with an open or closed system pump depending on the parts installed. As you say, these are usually - but not always - the type of SCVs that are made in sections. Also, sometimes the SCV does have a plug that can be exchanged to change its application. My comment was meant to warn you that you cannot count on this convertability in most SCVs.....particularly the ones commonly used as two spool loader control valves. That optional ability makes for a costlier valve than most loader manufacturers want to provide. I assume that if you have one with both abilities then you will know it.
"I am guessing that the nipple on the end plug blocks the open center through the work sections from reaching the outlet. Perhaps simply removing the material will change the configuration?"
Well... MAYBE....above..
"I do not understand when you say the attachments are the same, and it is the output connections of the tractor that are changed. Are there some tricks I do not know about? I would think it is strictly dependent on the attachment valve."
Whoa! I think we need to back up a step. Maybe we took too big of a step right at the first. It is the HYDRAULIC PUMP in the tractor that determines whether you have an open or closed hydraulic system in the first place. You do not have a choice as to what kind of valve you want to use. It is determined by the pump in the tractor. Period. Almost all older compacts tractors as well as all PTO or crankshaft nose-driven hydraulic pumps are open center.
An open center pump has constant recirculating flow and develops pressure when the flow is restricted. Conversely, a closed center pump maintains a constant pressure and develops more flow when the pressure drops. They are worlds apart.
A better way to interpret my answer would be: Regardless of which pump the tractor has, the job of the tractor is simply to provide hydraulic flow to the implement.
Regarding the weight of the Bradco. I don't know the 7LD model, but you might want to check. The smallest Bradco I know if is the 3375 series and it weighs 1100#. Bradcos tend to run about 50% heavier than Kelly, Bush Hog, or GB. for the same lift and depth. And those lighter hoes are more than adequately strong.
