Hmm, såhär står det på Marvins sida:
The flipper bushing is a nylon part that the flipper shaft passes through. It is very common for this part to crack, or wear excessively. This can cause the flipper bat to drag on the playfield finish. If this happens, ugly playfield wear marks can result (see picture above). It's pretty easy to tell if the bushings need to be replaced. With the flipper pawl removed from the flipper shaft, wiggle the flipper on the playfields, side to side. There should be some play, but not excessive play. The bushing should also stick up ABOVE the playfield about 1/8". If the bushing is too low to the top of the playfield, this will allow the flipper bat to drag on the top of the playfield. To play it safe, always replace both nylon flipper bushings. Flipper drag marks on the playfield are not worth the risk!