In a pump arrangement, each adjusting screw has first and second end portions, a third intermediate raised portion, and a fourth portion to allow each adjusting screw to be rotated clockwise/counterclockwise. Each first end portion passes through a suction liner aperture so left-handed threads couple to a respective left-handed seal ring aperture. Each second portion passes through a suction half casing aperture so the fourth portion can be accessed to allow clockwise/counterclockwise rotation of each adjusting screw. Each adjusting screw rotates clockwise and moves until the third portion pushes against the suction half casing, so the screw stops moving and the seal ring moves away from the suction liner as the screw is rotated clockwise, or rotates counterclockwise and moves until the third portion pushes against the suction liner, so the screw stops moving and the seal ring moves towards the suction liner as the screw is rotated counterclockwise.