It's easy to replace the grommet without bits falling in: drain all fluids, hold the car upside with one hand and use needle nose pliers to grab the grommet and pull it out. If it cracks and falls to pieces, the bits just fall on the floor. Set the car down and put the fluids back in.

This is how I did mine. Learned the trick from my friend, Chuck.

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Cheers!
Scott McPhee

1987 300D