OP
CHDinCT
Veteran Member
Ip333, just saw your post with questions. I'll see if I can help you out some. While there may be a hydraulic circuit diagram in the BX25 Work Shop Manual (available for purchase from any dealer), I didn't have one but really didn't need it. I can tell you that the three connections for the backhoe consist of a pressure in line (which is the male ended line that when un-hooked extends about a foot out from the tractor), a power beyond line which is the line that plugs into the female quick connect on the tractor just to the right of the top link bracket, and finally the return-to-tank line which is the line that has a female end and plugs into the male QC just to the left of the top link bracket.
When the backhoe is connected to the tractor, pressure flows from the pressure in line through the backhoe valve and out to the power beyond line so as to feed pressure to downstream vales on the BX. This is the case when no functions on the backhoe are being used. As soon as you use any BH functions, pressure is diverted via the BH valve to whatever cylinder is in use and low pressure oil on opposite side of the cylinder is feed through the BH valve back to the HST tank via the return-to-tank line.
In my set up, I looked for a two spool valve with a power beyond function and in essence put it in place of the BH valve (conceptually). I hooked up the pressure in from the tractor to the pressure in port on the new vavle, the power beyond port on the new valve to the power beyond port on the tractor, and the tank return line on the valve to the tank return port on the tractor. When set up this way, pressure is fed through the new valve and down stream to other functions whenever the valve is not in use. When in use, the valve re-directs pressure to one of the two pairs of ports and then back to the HST tank via the tank return line on the new valve. To use the backhoe via the new valve, I used one set of ports on the valve to feed the pressure in and power beyond hoses on the BH and then hooked up the tank return line on the backhoe to the tank return line from the new valve via a "T" fitting.
Well, this may be hard to explain via works, but if you start with knowing which connections at the rear of your BX are for pressure in, power beyond and tank return (as I laid out above), you'll know how to hook them up to your new auxilliary valve since the new valve's ports will be labeled when you get it. If you attempt this project, start a new thread (my recommendation) and ask lots of questions and you'll get plenty of help from the hyraulic experts on TBN, which assuredly, I'm not one of. So I guess I could say, if I can do it, so can you. Hope some/any of this helps.
