Injector Replacement/Seal RIng

I parked the 87 300TD wagon today for heavy maintenance. After doing all the filters etc, I decided I would clean the intake crossover manifold and remove two injectors that were seeping black fuel/oil at the base. I had picked up two steel rings that go at the bottom of the injector. This is my first venture into the injector area. Armed with my trusty socket and breaker bar, the injector broke free and came out. Unfortunately, the steel ring at the bottom seems stuck. Does it need to be muscled out or does the "prechamber" need to come out? Should I just torque the sucker back in and forget it? How common is this seepage?

All else went well and I am ready to put her back together after I hear back from one of our experts. The cross over tube was pretty well gunked up, especially right at the elbow where the EGR vents in. I had plugged it about 6 months ago, and just got around to opening up for a look see. Many thanks MercedesShop/PartsShop and members for the parts and guidance in this area!

BTW, I changed the oil while it was hot and I am letting it drip over night!