裝載機制動系統中，選擇閥的作用是切斷或接通雙管路氣制動閥通往變速縱閥上切斷閥的氣路，使山東裝載機自動脫檔切斷驅動力矩。
Shandong loading machine brake system select valve is cut off or connected dual gas brake valve leading to variable pitch valve cut off  valve in the gas path, Shandong loader automatic disengaging cut the driving torque.

裝載機正常行駛和作業時，制動系統選擇閥的常見故障有頂桿卡住和漏氣。頂桿卡住不能回位，踩制動時變速壓力為零。山東裝載機不再傳遞扭矩，變速壓力為零，掛檔不管用。原因是頂桿因空氣中的水分侵蝕而生銹，卡住不回位。山東裝載機排除方法就是拆下選擇閥，解體清洗。必要時，更換新件。
Shandong loader normal running and operation, the common fault of the brake system selection valve with a top bar stuck and leakage. Top  stick can not return to the position, the speed of the brake when the variable speed is zero. Shandong loader no longer transfer torque, speed change pressure is zero, the file does not work. The reason is because of the air in the top of the water erosion and rust, stuck not  back. Shandong loader exclusion method is to remove the selection valve, the disintegration of cleaning. When necessary, replace the new  part.