Originally Posted by terry welsh
I am in the process of fitting a simrad
NAC 3 auto pilot computer and RPU 160 reversing pump to a hydrive admiral twin helm steering
To bleed the pump I need to get the port and starboard remote
switch controls working but I can't do this until I commission the autopilot. One of the steps to do this is to test the rudder (the rudder feed back has been calibrated).
When I start the rudder test the pump runs but the test fails and goes back to rudder test display.
Does anyone know any way to bleed the pump to pass the rudder test or bypass the calibration of the autopilot?
Terry on TVtinney
I learned the following from a technician that helped us with the drive on our Simrad AP that has been restored to health
following a rebuild
The pumps are self bleeding through a one-way valve (similar to the valve in an anti-siphon loop) on the top of the hydraulic fluid reservoir. Check the reservoir to ensure that you have adequate fluid (a piece of a bamboo skewer makes a good "dip-stick" ) then seal the reservoir and, with the AP powered up, manually turn the wheel
from lock-to-lock quite a few times. Recheck the fluid level and add oil
as necessary after which you should be able to use the direction buttons on the control head
to move the wheel
back and forth a quarter turn or so each way during the course of which you may hear a moaning sound caused by escaping air through the bleed valve. Recheck the fluid level and add fluid as necessary and repeat until the moaning stops after which you should be good to go.