Brown and Sharpe No 5 Surface Grinder - problem with hydraulic valve

I have a B&S Number 5 I bought at auction for my knifemaking shop. The hydraulic start stop lever will not actuate. More specifically, it seems that the pinion that lever should rotate to engage/disengage hydraulic pressure to the rest of the system is seized up solid.

I've attached a diagram of the circuit. With the pump running or not, nothing I do seems to have any effect. Indexing the cross feed latch, changing any of the controls, indexing the table manually, the direction change lever manually, etc. That pinion gear just will not budge. It's stuck way up in there so I cannot really get after it with anything but I did try prying behind the rack while pulling the lever to put some extra force on it, in case it was glued in place by varnish/wax/oil but to no avail.

Any ideas what may cause this? I'm not really set up to remove the table and the saddle, then the valve. I can figure out a way to do it if I have to, and since the access to this valve is so limited that may be my next step, but was hoping someone would have some insight into whether that would be necessary or could be avoided. I'm having a hard time imagining what would seize that pinion up to this extent.

Well, to update in case someone with a similar problem finds this in the future, it was in fact just old oil varnish that glued this valve spindle in place. This machine must have sat for a good period of time. The spindle has no seals, so it obviously leaks under pressure out the ends, but it is of course a very tight clearance fit, and did not take very much build up at all to seize. There's really no mechanical advantage, and actually probably a disadvantage, as the pinion OD is smaller than the spindle OD.

After removing the retention screw from the spindle I pushed it through the valve body. The first few whacks it didn't move, then I felt it break free and come out relatively easily. Cleaned up the varnish in the pic below and it now rotates free as can be.

My biggest challenge now is remembering where the 87 taper pins I had to remove to get to this point belong.



Also, FWIW if you have to pull one of these apart in the future. Table comes off with one bolt connecting the hydraulic cylinder. Apron is similar, but there's another shaft for the cross feed that has to come off, removing the rear coolant cover provides access. You must also disconnect the main hydraulic flexible hoses, there are spinnable unions down by the filter. I had to take the pump off as well to get a wrench on them. With the apron off, remove the hand wheels and control knobs, then the front face casting can come off with 4 big flat heads(and a couple hydraulic lines). (You NEED a flat head with a right angle like a Wadsworth mini-ratchet, they are torqued down HARD) With the front face off, you can then remove the table direction toggle linkage to the valve, the start stop lever by removing taper pins in the rack that engages the pinion.