Has anyone made a diagram for CMC actuator tilt/trim valves/check balls?

[62Scout]

Another case of CMC actuator leaking and not holding position. Pulled it apart, took it down to the local hydraulic shop and got all new seals for it - the 4 small pistons in the plate, the quad seal and spacers, rod bore seal, and the two between the plate and body. Got the seals installed, filled with oil, and bench tested it...

The rod extends very slowly, and the pump isn't dead heading at full extension like it should. Retracting works perfect - goes up quick, motor slows ever so slightly when it starts retracting and dead heads when it's fully retracted.

I've read a couple dozen threads across multiple forums on these things, all saying the same thing - make sure to put check balls back in the same place..but nothing about where they're supposed to go when all the pieces just fall out on the bench...or the positions of the two valves with two o-ring grooves, but only one o-ring installed. Or did I have two o-rings that disintegrated?

Looks like there's only two places that the steel check balls could even go, but I've seen mentions of brown plastic balls over the springs too. Which I never saw. I have two springs with tiny brass looking top plates on them, near the rod bore?

So now I don't know..did I assemble it wrong? Are all 4 of the small pistons supposed to have two o-rings? Did I mix up positions? Do I just bend over and order a new actuator?

 

[dingbat]

Another case of CMC actuator leaking and not holding position. Pulled it apart, took it down to the local hydraulic shop and got all new seals for it - the 4 small pistons in the plate, the quad seal and spacers, rod bore seal, and the two between the plate and body. Got the seals installed, filled with oil, and bench tested it...

The rod extends very slowly, and the pump isn't dead heading at full extension like it should. Retracting works perfect - goes up quick, motor slows ever so slightly when it starts retracting and dead heads when it's fully retracted.

I've read a couple dozen threads across multiple forums on these things, all saying the same thing - make sure to put check balls back in the same place..but nothing about where they're supposed to go when all the pieces just fall out on the bench...or the positions of the two valves with two o-ring grooves, but only one o-ring installed. Or did I have two o-rings that disintegrated?

Looks like there's only two places that the steel check balls could even go, but I've seen mentions of brown plastic balls over the springs too. Which I never saw. I have two springs with tiny brass looking top plates on them, near the rod bore?

Not familiar with that particular actuator but....misplaced check values typically prevent motion at all.

Sounds like motion is operating more or less as designed, but you have air trapped in the system.
Have you tried bleeding the system?

I've had problems with self bleeding units if completely drained of fluid.

 

[62Scout]

I've had problems with self bleeding units if completely drained of fluid.

Manual simply says to fill with oil, run the ram all the way down until the motor bogs, run the ram all the way back up, and replace filler plug.

I've ran it up and down a dozen times checking and adding oil afterwards as needed. After the 3rd or 4th cycle, the oil level stays full, but it never bogs at full extension. It also takes a minute plus to extend, whereas it will retract in about 10 seconds. I'm doing this all on the bench, so there's no load on the cylinder (which the manual says is acceptable to do).