brettski
New member
I purchased a backhoe, FEL, and hole auger new from a factory in China this past spring. Yes, it was and is a risk and I knew that going in. I am pretty comfortable with wrenches and mechanics, so I let the price make the final decision. In the end, it played out about as well as I expected. All 3 items had some issues. The only issue that I cannot definitively resolve is with the backhoe.
It is an LW7 knockoff, if not the exact model since so many of the Chinese factories build and market their own version of the LW7. It has an on board, PTO driven pump and tank. Right from the beginning, it had low power. I could not curl the bucket thru firm clay loam at a 6" deep bite. If I stretch out the boom and dipper to full horizontal extension, it struggles to pull it back up.
I removed the hose on the dipper and put a 5000 psi gauge on it. The dead head pressure bumps 1300 psi, then precipitously drops to 1000 psi in about 4 - 5 seconds and holds there. I can hear the rush of the pressure release bypass occurring. I adjusted the pressure relief valve, 1/2 turn clockwise; no change. Another 1/2 turn, no change. About 2 total turns and it was buried; no change. I disassembled the PRV all the way down to the check valve ball bearing. It was clean. I cleaned and blew everything out anyway and reassembled. No change. I disassembled and added a couple of small stainless steel washers to the top of the PRV spring to really push it down. No change. I removed the test washers, re-assembled, and gave up.
What next? How does one analyze these findings? Does any of this point to the pump as the culprit? I can find no ID on the pump, but I was told by the factory that it produces 2600 PSI and 8 gpm. These specs seem fair, but how do I know that it is actually working as designed?
It is an LW7 knockoff, if not the exact model since so many of the Chinese factories build and market their own version of the LW7. It has an on board, PTO driven pump and tank. Right from the beginning, it had low power. I could not curl the bucket thru firm clay loam at a 6" deep bite. If I stretch out the boom and dipper to full horizontal extension, it struggles to pull it back up.
I removed the hose on the dipper and put a 5000 psi gauge on it. The dead head pressure bumps 1300 psi, then precipitously drops to 1000 psi in about 4 - 5 seconds and holds there. I can hear the rush of the pressure release bypass occurring. I adjusted the pressure relief valve, 1/2 turn clockwise; no change. Another 1/2 turn, no change. About 2 total turns and it was buried; no change. I disassembled the PRV all the way down to the check valve ball bearing. It was clean. I cleaned and blew everything out anyway and reassembled. No change. I disassembled and added a couple of small stainless steel washers to the top of the PRV spring to really push it down. No change. I removed the test washers, re-assembled, and gave up.
What next? How does one analyze these findings? Does any of this point to the pump as the culprit? I can find no ID on the pump, but I was told by the factory that it produces 2600 PSI and 8 gpm. These specs seem fair, but how do I know that it is actually working as designed?