Hi, apparently the end-caps of the 420lf separate and the motor de-cans - I did a web search on this and there are a goodly number of entrys that seem to make this not a fluke but a real problem. Align now put screws on the end-caps on the 430 - but one thing you can do is use tie-wraps around each end of the 420, (almost covering the crack-interface between the motor and the caps) and carefully flow a good grade CA between the tie-wrap and the crack. (when my 420 wears out I will replace it with a Align 430 or JGF 450TH anyway - so no need to be able to open it in the future)