Leica Builder Series User Manual page 187

On the tribrach
step-by-step
Builder, Check & Adjust
1. Level up the instrument with the electronic level, assuming that the electronic
level is correctly adjusted. Refer to "5.2 Instrument Setup" for more information.
Then remove it from the tribrach.
2. The bubble of the tribrach must be centered. If it extends beyond the circle, use
the adjusting pin in conjunction with the two cross headed adjustment screws to
centre it.

After the adjustment, no screw shall be loose.
187