With the pop-up probe extended attach the linkage assembly  to the trap box lid  with the two BHCS . Leave the bolts  loose at this time.
Retract the pop-up probe.
With the probe retracted make sure that the linkage mounting bolts  have some free movement in the slots. If the bolts are bound-up against the perimeter of the slot check the alignment of the linkage base in step 3.
Tighten the linkage mounting bolts  in small increments until snug.
Extend the pop-up probe.
Finish tightening the linkage mounting bolts  while observing the movement in the links . The linkage mechanism should not have any bind or tension and you should be able to move the links and the lid a small amount by hand. Bound-up linkage will cause the probe repeatability problems.
NOTE: If binding occurs, the screws that fasten the box to the cylinder body  can also be used for adjustment.