If that's a spiral ring, you probably need to "unscrew" it from the three ears. It should be flexible enough that you could do that. Like 2ManyTrucks suggested, maybe the plug needs to be screwed in a bit to release the pressure on the ring.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
