...does the cylinder work fine Before you put it in the the door? I know my 52 are different but I believe my back panel door is like your front door. When I installed mine I had somewhat the same problem. I took the lock and latch back out and tried them on the work bench to see if it'd work there.
It was still "stiff" until I greased all the part real good. Then the lock got easier to lock and unlock. Back in now and works good.
Don't know if this helps but just sharing my experience.


1937 Chevy Pickup
In the Gallery
1952 Chevy Panel
In the Gallery
More photos
1950 Chevy Coupe
Pictures!

I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
I can explain it to you, but I can't understand it for you smile