I have two helms and added a garmin autopilot. The helm stops turning once the Cylinder is fully extended or retracted but if I hold pressure on the wheel it will turn another quarter to half turn after a few seconds and keeps slipping with continued pressure. If I lockout the AP pump using the shutoff screws on the manifold the steering slip disappears. I have bled the system a couple times using the method posted by Bob(connecting the cylinder hoses) turning both helms 30+ times and running the AP pump for several minutes. I am trying to figure out if this is a faulty check valve or air bubble in the AP pump. The pump does not have a bleed valve. Would love to hear if anyone has similar steering wheel slips while holding pressure at the end of the turn range. Steering via the helm or AP works fine but the slip is annoying when I am trying to do a tight turn and I feel the wheel slip.