Case CX14 low/no hydraulic power

[lantraxco]

I'm kind of guessing maybe a real cold start or two might cause this? I'm no pump expert but it looks to me like the plate that holds the feet may have lifted and allowed the feet coming around on the pressure side to "float", I can't think of any other reason why the piston feet would get chewed off on the outer edges like that, they kind of had to have been tilted, yeah?

If the pins are the same length by eyeball that should be good, might check the height installed, there's a mondo spring in the center of the cylinder they push on, it's rare but maybe the spring is broken or cocked.

 

[blankey85]

Well my brother did try to use it one day when we did have a fair amount of snow and seemed to be about the start of the issue. You might not be a pump expert, but are surely close enough!

So the thin metal plate (part #6) should be up around the feet and swivel on part #4?

I was wondering what the spring inside the cylinder was for. It looks ok, but I didn't remove it.

So where will I go about ordering parts for when the time comes?

 

[lantraxco]

Yes, that plate keeps the feet flat against the swash plate. The spring is held in by a snap ring on the port end of the cylinder, it pushes on the three pins, the pins push on the ball #4, it pushes on the plate, which pushes on the backside of the feet, whole thing is tensioned in the pump housing.

The default state is for the swash plate to start at maximum angle, I'm guessing if the oil was too cold, it couldn't flow in to fill the backside of the pistons fast enough. At best you only have atmospheric pressure (14 psi?) in the tank to push the oil when the pistons pull out of the cylinder. If the oil can't move in behind the pistons, no matter how strong the spring is the piston feet will not follow the swash plate at the part of the circle where the pistons move from suction to pressure, the pistons still in the suction part of the circle will hold the plate back lifting the plate off the feet moving into the pressure part of the circle and the minimal pumping action will actually push the pistons out a bit, so the feet will be flailing around without guidance sort of crashing into the swash plate until the gap is closed. If that makes sense.....

Not sure about parts since Case has disavowed all knowledge, but you might try this place, they're a Nachi dealer:

http://www.lifcohydraulics-usa.com/index.html

 

[blankey85]

So the Case dealer was partially helpful and could get some of the parts within a couple days and the rest being 30 days out. The Kobelco dealer ended up finding a pump rebuild kit in stock at a dealer in Texas, so they had it shipped.

I rebuilt the pump and got it installed. Magically when you push the control lever cylinders start to move again! Now my next question is about the set screw on the pump that pushes against the spring. Do I adjust this to control the max pressure that the machine should see? Is it a combo of that set screw and various relief valves? I had the flow meter and pressure gauge hooked up at start up and was watching the pressures as we were testing functions. Some of them seemed to spike quickly at the end of their stroke. I just don't want to screw anything up.

Thanks!

 

[lantraxco]

Great!

I'm not sure about that adjustment, since this is actually two pumps in one.

You will see the pressure spike up at the end of cylinder stroke, that's normal, what you should not have is the relief valves popping open.

Your dealer *should* be able to give you the proper spec and procedure to adjust to. Since the system relief valve spec seems to be 3,000 psi, I would suggest that the pump should destroke at a somewhat lower pressure than that on one outlet port, but I'm guessing. You don't want the pump set higher than the system reliefs, that would never be right in my opinion.

This pump is supposedly designed to limit power load on the engine, so if you find that when you're working it hard with the throttle maxed that the engine seems to struggle, back the screw off a quarter or half turn at a time maybe, until everything seems happy would be what I would do in the absence of the factory settings.

 

[blankey85]

The set screw/spring are what controls when the pump destrokes, right?

 

[lantraxco]

Right, as I understand it the spring balances the hydraulic pressure directly by controlling the swash plate angle, the higher the backpressure on the pistons the more the spring compresses and the less oil is pumped, to the point where balance is achieved, if the pressure gets high enough basically the flow will drop to zero and the pressure is at maximum.