What if the knob that adjusts the cushion doesn seem to be tightening into the slide?
It is not necessary to totally remove the knob from the slide assembly when adjusting the pad. However, if the knob should become unattached from the assembly, check the tubing to be certain the metal insert is aligned for the knob to fit. If you are unable to locate the insert, strike the plugged end of the tube on a hard surface so as to dislodge the insert. Then align the hole in the slot so the knob will turn into it and tighten.