Rear Glass Pins

how hard are they to install? how effective are they? need some input, 'coz i've tried everything to keep my rear glass in place but it's too damn stubborn 'coz of the accident the previous owner had. it don't fit right.
they're the pins on the lower corners of the glass. would appreciate comments and suggestions. thanks

they're the pins on the lower corners of the glass. would appreciate comments and suggestions. thanks
