Xerox Paser 7400 Service Manual page 294

6. Twist the guide slightly clockwise, free the engagement of the paper surface
detecting lever (rear), and then remove the guide.
Paper Surface Detecting Lever (Rear)
Replacement Note
Be sure to insert the paper detecting lever in the groove of the paper surface.
After completion of mounting, activate the paper detecting lever several
times to make sure that side guide is mounted securely.
5-108
Groove
Phaser 7400 Color Printer Options Service Manual
Paper Surface
Detecting Lever
(Middle)
s7400-280