61 560 spool valves

cut 10 acres with my 1961 560 and when raising or lowering the cutter bar on the case 555 I noticed it would raise fast but lower slow. It seemed like it was set for a single acting cylinder but per my owners manual it was in the dual acting setting. when I tried to move the position with a 9/16 wrench I couldn't budge it. How hard is it supposed to be to move the setting? Do you think this may be where my problem lies? Thanks all help appreciated....Fred

While I can't give an answer specific to your setup, I might offer a bit of general hydraulic insight.

Not knowing the gpm of your pump, or of the size of the cylinder on your cutter, or how the cylinder is set up on the 555, but the physics of hydraulics say that the 'retract' will be about 30% faster than the 'extend' of a 2 way cylinder, because it takes more volume of oil to fill the cylinder on extend, and less on retract because of the space the rod occupies. This would be more noticeable with a low gpm pump. It could also happen if the valve has scoring or a blown O-ring inside that is allowing some blowby in one direction. Some hydraulic valves have built in flow controls, which can adjust the rise or drop rate. Yours probably doesn't.

IOW, it could be a pump issue, or a spool valve issue, or a even a hose issue. Short of doing a flow check on the pump, your best troubleshooting step is reversing the hoses and see if the problem reverses. If it does, the next step is tearing the valve apart to check and clean. It could be something as simple as a worn pin that isn't allowing full spool travel, or even a wad of teflon tape stuck in a hose coupling.

Hope that helps.

Pretty easy to tell if your valve is set for single or double action. Just hold the lever on demand after the implement has reached it 's lowest position and see if the hydraulic system cause engine to labor due to pressure build up. If it is set on single action the hydraulics will not go under pressure in that direction. Actually, it will make little difference if double or single as for lowering speed. You must have a restrictor in the system some place. Often added at the end of a hose to slow the drop. If you have a factory type check valve under your aux valve that is no doubt the restriction. It is to keep load from sagging when load is up. If that is the case, just hook around it to other outlets above the valve. As far as how much pressure to turn the single to double, well, they get rusted pretty tight but should turn easily.