装载机制动系统中，选择阀的作用是切断或接通双管路气制动阀通往变速纵阀上切断阀的气路，使山东装载机自动脱档切断驱动力矩。
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.

装载机正常行驶和作业时，制动系统选择阀的常见故障有顶杆卡住和漏气。顶杆卡住不能回位，踩制动时变速压力为零。山东装载机不再传递扭矩，变速压力为零，挂档不管用。原因是顶杆因空气中的水分侵蚀而生锈，卡住不回位。山东装载机排除方法就是拆下选择阀，解体清洗。必要时，更换新件。
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.