Potential Brake Problem for 92 Caravan

So I'm going to have plead my ignorance from the start. I know little about vehicles. I have some background knowledge, enough for basic maintenance. But the latest problem I am encountering is beyond me.

I ran over a tire tread on the freeway on Friday, had no reaction time due to the car in front of me, and as a result a piece of my car busted. I have no real idea what the piece is, but from what I can gather, it seems to be a ground for a brake system. The damage was incurred on the driver side towards the rear tire and is situated in proximity of the brake lines. I have little time until the 27th to deal with this in real time, so I thought I'd toss the question here......Can anyone discern what the piece is that I am talking about? It looks kind of like a pump.....the brakes still work, as determined from an hour drive home that I was very hesitant and cautious with, however, I am certain that I need to know more........

Not to sound like a wise guy, but how do you know the part you found came from your vehicle? Also, to sound like a wise guy, if you couldn't react because of the car in front of you then you were following too close. Sorry ! Pet peave of mine !

I took the part off my vehicle. It was hanging from what I assume to be the ground point. Understand your pet peeve.......but I would like to respectfully point out that the issue is not how close I was following, though I will remember your implied advice for the future.........

My 2 cents: take it to your local dealer and ask them to identify it. They should be able to tell you if it's essential or not. Peace of mind is priceless. Please let us know what you find out.