4200XL hydraulic issues

[Lil Giants]

I think it's a valve center issue that you have... if the 4th valve turned one or two splines when you changed out servo, that would throw off your mixing of it. How does the pump motor sound with pump on & no stick movement, does pump motor sound like it's laboring? Any change in motor speed/sound with stick movement of valve cyl servos?

You could either pull the 4th valve servo out & turn valve by hand to try to block the oil flow back to tank, then try your cyl movements. Or you could adjust center point in radio settings of 4th valve servo, all the way + or - while a valve/cyl servo is activated.

You still have your external prv to prevent any line ruptures.