Any hydraulic experts out there?

[nosocks]

Any hydraulic experts out there?The hydraulic steering for my autopilot stopped working. (The head and fluxgate check out.) My guess is the fluid is contaminated and has air in it. In three seasons the fluid has gone from clear to deep amber. I’ve added maybe 2 oz of fluid in that time, directly to the overflow tube. Can’t figure out how it got contaminated, but can’t figure out why it changed color either.This season the pilot won’t hold a course and I can turn the wheel to about 4 degrees of ruder to each side before I feel and hear the hydraulic system resist.Any ideas will be greatly appreciated, especially before I tackle the messy job of flushing the system.

 

[larry w]

hydraulics

It sounds like there is air in the system. That's almost always the problem with any hydraulic. There should be bleed points here and there, small screws or small bolts near the ends of rams and hose runs usually at high points. Locate these, loosen them one at a time, then have someone turn the wheel full right then full left. watch for air coming out, similiar to bleeding a diesel engine. when no more bubbles come out, close them. you shouldn't have to add fluid to an over flow, there should be a resevoir somewhere, preferebly with a sight glass so you can see a low fluid level. the amber color is normal, it just means the fluid has been in the system and working for a while. Good luck.

 

[Gord May]

Fluid appearance

Color is not a reliable indicator of hydraulic fluid quality, and there is no in-service specification for fluid color. Modern hydraulic fluids are often clear-purple (new & unused), and usually change color during service. The fluid should be clear (transparent) with no phase separation, cloudiness, or suspended solids. A milky appearance implies contamination by water.A DARK amber color (varnish) can indicate a thermally stressed fluid.The fluid should have a mild petroleum odor.

 

[nosocks]

Thanks

Bleeding is a lot easier than replacing all the fluid. I'll try that and let you know.