John Deere 280 series 2 charge pressure

[andy4020]

I am working on a Deere 280 series 2 fixing a hydraulic oil leak. my problem is when i use any hydraulic function my charge pressure goes up. When everything is in neurtal charge pressure is at spec of 450 psi. When i use auxilary function charge pressure goes up to 1800 psi and blows the gasket on the end of the front servo piston.

 

[andy4020]

just retested with cab down and charge pressure goes up when any of the hydraulic functions are dead headed. Is the problem in the priority valve on the gear pump or in the main valve assembly?

 

[Tazza]

just retested with cab down and charge pressure goes up when any of the hydraulic functions are dead headed. Is the problem in the priority valve on the gear pump or in the main valve assembly?

Could it be a plugged hydraulic filter?
That is very weird, no reason that i can see why it should spike like that.