how to setup a hyrauilic excavator on a 6channel?

[cosworth34677]

i did it was a spektrum digital programable sevo and it works fro one freakin day . i have had this excavator for about three weeks and allready gone through 6 servos, is it the the end point thats killing them or 6v instead of 4v? i don't know but i can afford to be buying servos every week end !!