[DeTomaso] Ignition Switch Question

[jefude at bellsouth.net]

All,
Over the 15 + years of owning #4134 I have always had occasional problems with my ignition key cylinder popping back out when removing the key. It springs back from the start/run fine. Usually I just put little downward pressure as I remove the key and it does pop out. However, occasionally I forget and the lock cylinder stays in. My trusty paper clip always at the ready in the ash tray is my specialty tool of choice.
 
Last year I reconditioned the electrical portion of the switch and I thought I had cured the problem. The problem has returned and I am looking for a final /correct repair. 
In searching old threads there seems to be no definitive answer on what causes this problem.

My question is the pop out spring in the electrical side 
of the switch or the mechanical cylinder?

Jeff