WELCOME Aleksey. Which screen? Discussion so far has been about the glass oil level sight. Typo? No worries, anyways the solution seems to be to open that side cover before any damage occurs and re-install glass and it's metal cage. Speculation here but maybe get everything very clean, lightly butter up hole in case with JBWeld, or equivalent, then press in sight glass assembly as much as possible? Carefull epoxy application from inside around margin should hopefully complete locking old assembly in place. Q-tip with acetone can clean up any errant epoxy from glass before it cures.