If you walk inside the main valve spring soft or broken, or the valve is stuck, are likely to cause lower oil pressure, appear to walk deviation. Check, walking the main valve to measure the oil pressure, normal if 32.5Mpa. If you walk the main valve is damaged, replace or repair. My unit PC200 excavator has twice appeared walk deviation, are due to damage caused by walking the main valve. Therefore, in the event of failure to walk deviation, you should first consider whether to walk the main valve is damaged variable pump * care to avoid detours. Variable type of pump output pressure is less than it is set at constant pressure variable pump repair phone *, full displacement output pressure oil, namely quantitative output, the output of oil pressure reaches the set pressure, it automatically adjusts the pump flow variable pump to ensure constant pressure, to meet the requirements of the system. Output constant value of the pump, if necessary, in the pressure range can be set stepless variable pump * refinement, the structure of the pump output pressure of the oil at the same time through to variable piston chamber and under the control of oil and constant pressure valve inlet, when the output pressure is less than it is set constant pressure, constant pressure acting on the spool of the hydraulic thrust is less than it is set spring force, damage. Variable pump maintenance *, variable pump, hydraulic from Jinan Jing Jing Chong Chong Hydraulic Machinery Limited. Jinan Jing Chong Hydraulic Machinery Co., Ltd. (www.jnjcyy.com) (www.jnjcyy.com) strong, credible, in Jinan, Shandong mining machinery industry has accumulated a large number of loyal customers. The company better work attitude and continuous improvement to create innovative ideas will lead crystal hydraulic and you hand into the brilliant, for a better future!