Rock in rear wheel

They have been grinding up roads all over Long Island (New York). I have lost 2 windshields in the past 3 months.

Last week I was driving on the Long Island Expressway when I saw a group of rocks strewn across the road. I couldn't avoid them, so I just slowed down as I passed over. I heard a series of rattles and bangs from the undercarriage of the car. But I also heard a loud continuous grinding noise that continued as I got off on the nearest exit.

When I pulled over, I got out of the car and looked under the car to see if there was anything there - no luck. When I got back in and started to move, the noise seemed to be gone. Unfortunately, as I pulled up in front of my house, it started again, with a vengeance.

I was going out of town that afternoon, so I didn't have time to do anything about it until I came home yesterday.

I started the car and put it into neutral. Then I got out of the car and rolled it back and forth by hand, listening for the grinding noise. I finally localized it down to the right rear wheel.

Here's what I found:

[attachmentid=11550]

It was hung up at about 1:00 O'clock between the wheel and the brake drum. When I got a large screwdriver to unwedge it, I found that it wasn't wedged in. It's shape was a perfect fit for the space. The screwdriver just popped it up and it fell the the ground. It doesn't look like there is any damage to the Drum, but I just don't want to take the wheel off and see how torn up the inside it's inside looks.