This is on 1964 Williams Heat Wave.
The right flipper would occasionally stick. I took the assembly apart enough to remove the plunger. Cleaned it, filed it down a little where it was rough around the end that hits the strike plate & cleaned the inside of the sleeve with alcohol and paper towel. It certainly feels smoother and faster. But now it won't hold the weight of the ball.
What'd I do wrong & how do I fix it?