1. Disassembly of the control valve assembly
Run the engine at low idle speed, operate the cylinder to the end of its stroke without overflowing the oil circuit, lower the working device to the ground, and then extinguish the engine to release the pressure in the hydraulic circuit. After extinguishing the engine, complete the following tasks.
① Slowly loosen the fuel filler cap to release the pressure in the fuel tank.
② Operate the control lever several times to release the pressure in the accumulator.
③ Start the engine and run it at idle speed for about 5 seconds, then stop the operation and operate the control lever. Repeat the above operation several times to completely release the remaining pressure.
2. The disassembly steps of the control valve assembly are as follows:
① Open the engine cover and remove the valve top cover and air filter top cover.
② Remove the cover of the partition plate between the engine and the control valve and the top cover of the bulkhead under the oil suction pipe close to the engine.
③ Remove the drain pipe and hose clamp of the pump.
Remove the self-reducing valve. When disassembling, pay attention to the different lengths of the mounting bolts. The length of the left mounting bolts (2 pcs) is 120 m, and the length of the right mounting bolts (2 pcs) is 125 mm.
⑤ Remove the hose between the control valve and the interrupter block, the hose between the control valve and the adjustment valve, the travel valve pilot tube, 2 boom valve pilot tubes and 2 overflow pilot tubes. Before removing the hoses, label them to distinguish them. Use casing nuts to protect the threaded joints and the conical sealing parts of the elbow joints to avoid damage.
⑥ Disconnect the connecting hoses of the two travel valves.
⑦ Remove the 2 LS valve pilot tubes. After disassembling the hose, attach a label to make it easier to distinguish.
⑧ Disassemble the adjusting valve and drain pipe.
⑨ Disassemble 10 hoses connecting each valve. After removing these hoses, label them
① Disassemble each bucket valve tube, boom valve tube and stick valve tube.
? Disassemble each right travel valve tube, rotary valve tube and left travel valve tube.
? Disassemble the 2 LS valve pilot pipes.
?Hang the control valve assembly, then remove the mounting bolts, and hang down the control valve assembly.
3. Control the installation of the pump assembly
The installation sequence of the control pump assembly is opposite to the removal sequence.
Fill the hydraulic oil tank and fill the oil to the specified oil level through the oil filling port. Run the engine to circulate the oil in the system, and then check the oil level again.
Drain air from the oil path between the control valve and the hydraulic cylinder.
4. Decomposition of control valve assembly
When the safety valve is installed on the machine, the limit pressure of the safety valve cannot be adjusted, so it cannot be disassembled.
