That's what I’m afraid of, this is a brake down of my valve, found this pic on another post. Doné�ž mind the red lines,that from the original poster .I suspicion that valve is not used on any of the American sold models and therefore you will not find a service manual for it. the 220/226 models and 276 have side mounted valves but not like yours.
It seems to me, that if that rod is adjusted from the orig. start or factory. That it has to be from somewhere else, to cause this reaction. Like was mentioned, a leak down from another valve. Maybe leaking around the o-ring in main valve. I wouldn't adj. that rod(unless you mark it from where you started from. Just in case, it's not it. Make sence?
Everything that I have taken apart that had O-rings all look good ,in the main valve there痴 one small o-ring and one small nylon washer and that痴 it ,everything else is metal to metal .Someone definitely messed with this before I did, I can tell from the paint missing on the bolts, on the control valve,I took pictures with a micrometer so I would know how it went back together. I still think the T bar on valve is my problem,just wish I had an idea where to send it . Thanks for trying to help me.
Unfortunately, since you are positive someone has been in there before l, you really have no ideal what might have been done.
Might I suggest replace the O-ring and nylon washer, they could easily have wear that allows a pressure drop. I would also suggest a close examination, if you have not, for wear on the metal to metal parts. Unfortunately, specs on these is hard to come by. Again Aaron at Hoye is one of the best resources I have found.
I would also suggest the ym owners group with Hoye. Hopefully, Aaron will pickup your thread tomorrow (Tuesday after labor day) or soon thereafter.
Another suggestion would be to clean the hydraulic screen and replace the filter (if equipped) if you have not done so. A restriction on either of these could reduce your flow rate enough to cause issues. As down force is controlled more by weight, gravity, and open valve status and not pressure or flow rate, it would be not be influenced by a clogged filter/screen.
A final suggestion since you have no ideal where to go, is if you decide to adjust on your T bar is to take slow adjustments and check for changes.
I will see if I can get the o-ring and washer, I pulled the screen looks new nothing in it at all, I went ahead and replaced the fluid so I know that is good. Thanks for all the input and help. Well on a side note I pulled my brakes to replace them, was told I probably should replace them, but dang they have more material then the replacements that I got ,so that’s a good thing,just needed to be adjusted.