Great Dane excavating co.

[Cooper]

http://youtu.be/ZQ2fhhMkTsY

Here is a video of a problem I'm encountering.
The valve center has been established and messed with so it's not drifting because of not being centered.

I completely disassembled the cylinder to check piston and shaft seals and replaced with new.

When I reattached the cylinder I worked all air out with temporary lines hooked up into glass of oil, then turned on pump to squirt oil out of lines before attaching to make sure air was purged completely from system.

I am currently hooking another spare cylinder up to valve to completely eliminate the lines, hard lines, and cylinder in question to see if it does same thing. Trying to trouble shoot everything before tearing apart valve. As that's the last thing I want to do, I've never taken one apart and don't know about seals inside or what sizes let alone having a spare if it isn't damaged and I damage it from removal.

In the video you can hear the squealing I'm referring to. I originally thought it was gears between motor and pump but now I'm thinking it is just oil being pumped. When I started it up this morning it was gone but returned. And if I'm getting air sucked into system I would surly think oil would be leaking out also. I have no leaks anywhere, valve, hoses, fittings, cylinder, all dry.

What do you guys think? Valve seal? I'll post up again on results of swapping cylinder out to see if it does same.