This tends to happen when the rubber wears off the ears at the top.
What i have done in the past is make sure the joint surface is flat and check the fit of a new blade, normally a new blade fills the holes at the top and the bottom pin is only just a fit so there is no vertical movement. You could use some of the rubber off the old cushion in the bottom of the slot but not enough to mean you need to press the cylinders down to get the joint to fit.
This, of course, assumes you are using it as a road bike and not going racing!!