Dear Customer,
Unfortunately, we currently do not have a suitable mounting bracket to install the Premium Cuboid Reservoir series on a 140 radiator. If you wish to use the Premium Reservoir Mount Bracket 140, you will need to enlarge the middle slot and use the appropriate M4 screws.
Or you can try the fan adapter, such as BP-FA140120-BK, and use the appropriate M4 screws and nuts.