Common causes of faults:
1. TVC valve is improperly adjusted.
2. there is a problem with the excavator servo mechanism.
3. there is a problem with the plunger of the Doosan excavator.
4. the excavator plunger pump or servo plunger is faulty.
5. The LS control EPC solenoid valve acts incorrectly.
6. Incorrect action of LS overflow or main unloading valve assembly will also cause the excavator to rotate, travel at low speed or lack of power.
7. the auxiliary unloading valve acts incorrectly.
8. the main overflow valve acts incorrectly, which will also cause the excavator to rotate, travel at a low speed or lack of power.
9. the hydraulic parts of the excavator control pump circuit have problems (refer to test and adjustment), which may also cause the excavator to rotate, travel at low speed or lack of power.
Maintenance methods for rotation, low traveling speed or lack of strength of Caterpillar CAT336 excavator:
1. adjust TVC valve.
2. replace or repair the servo mechanism assembly.
3. repair or replace the plunger pump.
4. correct or replace the excavator plunger pump or servo plunger.
5. replace the LS control EPC solenoid valve.
6. replace the excavator LS overflow or main unloading valve assembly.
7. repair or replace the auxiliary unloading valve.
8. replace the main overflow valve.
9. adjust or replace the hydraulic parts of the control pump circuit
