Ok this one has me runing in circle. ok i started with failing neg. stabiblity any way found my dearation pressure was low went to calibrate and cant get it to go about 20 without droping my loading pressure to hardley anything like 10. changed brushes on motor, voltage to motor is good. V 39 is not open the deaeration orifice is good new style bead in hose. Tryed different deaeration pump and pump head with same problem. and tryed diffent loading pressure valve and still have same problem. Do yall know of something i am skiping over?

I am thinking it might be an internal problem in the hydrochamber. If you have a salvage hydroblock try installing it and see what happens with your deair pressure. The hydrochamber is in two halves, and I haven't taken one apart yet, but maybe there is a seal or a fit surface there that has a leak. We had a hydrochamber in a two year old K that was making a loud noise, and we could not get rid of it. We installed a salvage hydroblock that we rebuilt with a new top seal from a retired H machine. Does it seem like the speed of the deair motor is correct? Maybe a bad actuator board is causing the motor speed to be slow. Check the voltage at the pins in the distribution board.