32 1 which also serve to mount optional shims the embodiment of fig1 may use four mounting bolts 32 1 that are spaced about the circumference of the spout the upper two of which are shown in fig labove the spout 16 and the other two of which are beneath the spout to engage a substantially identical portion of the cover 32 that projects beneath the spout the mounting bolts 32 1 pass through respective slotted holes 32 2 formed in the cover the slots desirably having a key hole configuration with the larger end of each slot permitting passage through it of the head of a mounting bolt in this manner once the mounting bolts are loosened the cover can be rotated slightly about its axis clockwise in fig1 to line up the bolt heads with the larger ends of the respective key hole slots to enable the cover to be withdrawn axially away from the subplate 34 as shown in fig2 any shims 30 that had been used can be removed at this time as well the split nature of the shims permitting them to be removed outward from the spout 16 wave spring 28 is then moved axially along the spout away from the drum as shown in fig2 to expose the split seal 24 and the split seal support ring 26 the split seal can be removed from the support ring manually by withdrawing the tabs 24 2 24 3 from the respective slots in the support ring and the split seal segments can then be removed easily and discarded a replacement split seal is then provided its tabs 24 2 24 3 inserted through the respective slots.