Does anyone here have one of these Chinese scissor lift carts (besides me)? I really like how heavy duty it is, but the hydraulic cylinder leaks down internally (not on the floor) and will not hold the table up in a set position for very long. I do not know anything about hydraulics, but would sure like to know how to fix this thing to hold it's position. I tried draining out the light oil and replacing with SAE 30 weight, thinking the heavier oil might help, but I don't see any improvement. Bill