My dump truck got a problem in the dump box it can not hoist up if its full, its ok if its empty . I suspected maybe the hydraulic cylinder get internal leaking. My question is how to check the single acting hydraulic cylinder of the dump truck if get internal leaking ? Thanks in advance.
Welcome to HEF Salgado. :drinkup If a single acting cylinder, like one on a dump truck, had an internal leak it would be dumping oil, and lots of it, on the ground. If the exterior of the cylinder is relatively dry, well no major leaks, then the problem isn't the cylinder, the problem is likely the pump is going south, or if the pump has an internal relief, could be dumping oil around the relief valve.
Does it lift at all when full. Could be a bad pump or incorrect bypass in the pump. If they are good lets assume that the top part of the single acting cylinder is used for oil storage and has a line from it to the control. If not it would blow oil out the vent either immediately or when you lowered it if bypassing oil past the piston. If oil is bypassing, the constricted flow past the internal piston seals will quickly heat the barrel up at the spot where the piston is stopped. If it raises part way do not trust it to hold while you check temperature. Use a temperature gun to safely check for a hot spot.
Willie, Not to argue with you, but some dump cylinders will have a waste line going back to tank from the outer end, so YMMV.
True, would be nice to know exactly how it's configured.
Pump is probably worn out... or it's overloaded.... pins are binding... etc ... etc... and etc...