Air in Hydraulic Fluid

[Snake]

Rick. I am text/email -ing with a Mech and now director of mx that worked for me while flying 337s. He asks is this in the brake or extension/retraction system. I assumed gear Ext-Ret. If you want to email me a full description I can send along to him. gryphonskymaster@gmail.com v/r snake

[Rick Erwin]

Originally Posted by Snake

Rick. I am text/email -ing with a Mech and now director of mx that worked for me while flying 337s. He asks is this in the brake or extension/retraction system. I assumed gear Ext-Ret. If you want to email me a full description I can send along to him. gryphonskymaster@gmail.com v/r snake

Hi Snake, thank you for trying to help with this!

For your Mech / Director of Maintenance:

• This is occurring in the landing gear system on a pressurized G model.
• We've made sure the hydraulic fluid reservoir is full, but not overfilled, when starting the tests.
• There are no visible leaks, that we've been able to find.
• The hand pump works great and does not appear to introduce air into the hydraulic fluid.
• The air is getting "whipped" into the hydraulic fluid so that the fluid turns an opaque pink color.
• The bubbles are so tiny it takes 2-3 weeks for the air to come out of solution.
• With air in the hydraulic fluid the pump makes a loud screeching noise, ...that noise is not present until the fluid is filled with air.
• With air in the hydraulic fluid the landing gear takes MUCH longer to extend/retract.

I'm wondering:
1) Could the pump be introducing the air?
2) Could there be a loose fitting in the system that could be "sucking" in air, in perhaps a return line?

Thank you again!

Rick