A friend has a PVC exterior door in the kitchen, on which the upper
hinge centre pin has a habit of rising from the hinge, which is the
top of three such fittings. When it first occurred, the door lock was
refusing to engage, and I rectified the problem by tapping home this
offending pin. That then aligned the door correctly. I did notice that
it has lost its plastic top seal, but assume that to be a dust cover.

Since then this pin has needed attention about once a month. Should
there be a circlip at the bottom to hold the pin in place? And why
would it tend to rise, defying gravity?

DJ