Brake light switch held by friction?

[gejandsons]

95 GMC ext cab. 4WD, 5.7 liter
Brake lights won't come on when pedal is depressed.
Hazard lights work, no fuses blown.
Installed new brake light switch,still no lights.
New switch will activate lights when operated manually, before installing on brake rod pin. Will not work when swith is installed. There doesn't seem to be enough resistance to hold the switch in place on the brake rod while the pedal is being depressed.
Is friction from the switch being snapped onto the brake rod supposed to be enough or should there be a clamp on the rod.
If any one has a parts breakdown on the pedal assembly it would be a great help.

Thanks in advance.
Resolved problem by replacing the new switch with another new switch.