Great Dane excavating co.

[Cooper]

Question for you guys, this is the pump set up they use,






It is four valves. But only three active cylinders. And the way they have it plumbed. Are they using the first valve to deadhead the pump and then mixed with other valves when input applied to sticks? I don't know much about these but that's not how I did the dozer. Would it hurt this style pump to change around to prv being the deadhead and then gaining another valve for say a thumb? And if so what advantage is this configuration? Or is a disadvantage ?

[Supermario]

Sorry to hear about your troubles with the excavator Ralph. I've got about 5 hrs total run time on mine and all has been good. Cylinders dry and no leaks in the body. I did have my first hiccup yesterday. The relief jammed and suddenly had so much power the stick function pulled the whole machine like there was nothing to it! After it cooled down things went back to normal.

Anyway, I'm a little embarrassed I never noticed myself but after seeing your post, what the heck IS the 4th valve for?

I'm off to the basement......

Mario