My 21 T I've installed the new reflector. Then the cord. Do you set the glass on now then twist the ring on? Or do you put the glass under the 4 clips on the ring...then twist the ring on?
Glass goes under the clips on my '27.
On my '19, I've found that putting the lens on the ring and twisting both at the same time lines it up perfectly every time.
The lens ring has the clips to secure the round glass lens on your '21. If you don't clip the lens to the rim, when at some distance future the rim is removed to change a bulb, that lens can fall to the garage floor, when you will be sweeping up glass pieces
On my '26 light buckets, I use a bead of clear GE silicone to secure the rope gasket to the reflector with the gap at the bottom to allow for drainage and then a bead on top of the rope gasket to secure the lens to the rope gasket then apply pressure and let it set up. This ensures a good seal against water leaking into the reflector and ruining it the delicate surface. This way the spring ring does not need to hold the lens against the reflector, but serves only to apply outward pressure to the headlight rim as you twist it on so it does not fall off. If you need to change the bulb it is a simple matter of prying the lens from the rope gasket. Jim Patrick
As my Ford shakes and rattles so much, like most others, find the Ford way of less parts the best.
4 parts to the headlamp, the bucket, the spring, the reflector assembly w/rope gasket cemented, and the rim w/lens attached to clips in rim. Bulb is optional
'20-'21 Ford two bulb head lamp illustrated
If you purchase a new ring you may have to file down the locking pins a little in order to get it to lock in place. I don't know how fussy you are about the Ford logo on the glass but if you want it at the top of your light then be sure to check the location before you spin the ring on.
I also found that if you use the heavy duty Platex rubber gloves that you get a better grip on the light ring to push in and twist it in place.