JD 450- 93- 93a backhoe

[jm003]

I have two valve bodies from 93 or 93a backhoes They appear to be the same except for the main lines hook up in different places. The one on the machine has one line on one side and one on the other. The broken backhoe has both lines on the right side as sitting in operators seat. Can anyone tell me what the difference is? The one on the machine doesn't seem to operate right at low rpm.

 

[J_J]

Can you identify the IN port and OUT port on each valve? Should be about 10 ports. What is the actual question? Is it , can I use either valve to operate the BH? As far as GPM's and speed of operation, that will vary on the cyl size. The more GPM's you have, the faster things will work. Have you checked the pressure?

 

[jm003]

The machine has plenty of pressure at the pump, the loader works fine, even at idle. The backhoe works only at about full throttle when warmed up. It will work some at lower rpm when first started. I seem to think that some where along the line, B4 I got this machine, possibly someone swapped backhoe units? The valve body on the machine,when looking at it from the rear, hooks up to the left lower port and the right port that is opposite the left upper port which is plugged. The other valve body that I have both lines hook up on the left upper and lower ports and the right port is plugged. Is one an open center and the other a closed center, and which is which. I also have a valve body from a series 50 that has the same left/right configuration as the one on the machine. I was thinking about changing the lines to the 2 ports on the left to see if it make any difference.

 

[J_J]

There should be some letters on the valve somewhere, identifying the ports. Be careful about just changing ports. You might try using air to ID the ports. A relief valve should be by the IN port. Some valves have optional connections for the IN and OUT ports, like top or bottom, or side. They use whatever ports to suit the situation.

Can you clean the valve up, and take some close up pictures?

It is hard to tell by looking at a valve whether it is an open or closed center, as the conversion is a plug, which looks similar to other plugs. On some valves, you can convert an open center valve to closed center valve by using the conversion plug.

 

[jm003]

I looked at it, it has two out ports and one in port. one out is above the in port and one is on the opposite end. What is the difference?

 

[J_J]

The two ports are just for mounting the best way. Side port or top port may not be accessible if mounted a certain way. Just options. One of the out ports may be a PB outlet, for another valve downstream.

This Prince valve shows different port connections. Note, that the one port on this valve is a PB port that is only used as a pressure port. for downstream valves. At other times, it has a threaded plug in it.

http://www.princehyd.com/Portals/0/products/valves/SVInstS.pdf

 

[jm003]

The diagram you sent still has the inlet on one end and outlet on the other end of the stacked valves. The ones that are on these backhoes have that hook up plus an in and out port on the same end, that's what does not make sense. I took the lines off one that is hooked up on both ends, it seems to be an open center valve bank, as I can blow air through it. I haven't got a chance to take the lines off the one that is hooked up one the same side yet, I'll let you know what I find out. Thanks, Jim