539/540 DT check found leak test out of ~~~~~ Check & found multiple car test pt was heavy air leak. Replace test point ok.Further check found #3539 CR joint,#2 end strained check v/v and water tank was air leak badly.Retightened ok.Conduct leak test on both cab-0.5bar in 5min. Done by Deeshan/Sanip/Faddzal. 21/12/20