Tractor Repair: case/ih 7140

Question
good morning
I have a 1990 Case/IH 7140 mfd. I have a front blade on it that needs all three of the remote valves. Number 2 and 3 work fine. Number 1 runs normal [lever forward] but extremely slow in reverse direction [lever reward] I have adjusted the flow control and it slows/speeds up when the lever is moved forward but does not affect the speed when the lever is moved rearward. I have switched hoses around, checked to make sure hoses are paired correctly,switched the couplers on tractor,no difference. I used a dummy hose inserted into each hole with open end in bucket. When lever is moved forward [top hole] flow is "normal" but when moved rearward [bottom hole] flow is noticeably slow. It seems to me the problem always comes back to the bottom hole. I am getting ready to replace the #1 valve which operates this remote. Do you have any advice to give me before I do this?  Thank you so much. Jim

Answer
Jim, I would tear the valve apart first to see if there is any obstruction...but I can tell you this: I have had the same problem with one-way-faster flow when using a baler like the New Holland 866, which allocates 2 valve blocks, and if there is ANY type of blockage in the lines, OR, if the rams are of a different size, you will have problems....but if none of those things are happening, tear the valve apart, make sure your hydraulic output is good us to that point, and replace the valve.