When installing or replacing Cybex strength weight tubes or pegs, make sure to use #680 Green Loctite to secure them to the frame.
Note: To remove the old weight tubes from plate loaded equipment apply heat using a heat gun. Twist and turn the weight tube using channel lock pliers or a pipe wrench. Once the weight tube comes off make sure the previous loctite is sanded clean with emery cloth or sandpaper. The tube on the frame must be clean before re-applying the new tube and loctite.
See What type of Loctite should I use? for more details