Help identifying brake rotor part

[oregon87]

While attempting to diagnose a growling noise from the right front of my 1980 911SC, finding a stuck caliper, I also found what appears to be some type of retainer in the brake rotor. Please see pic. In my haste and unawareness, I attempted to remove it, thinking it was a brake pad retainer pin clip. Needless to say it took quite a bit of effort to destroy while removing and I'm left with an uneasy felling as the same part is present on the driver side front rotor. What in the world did I break?

[Discseven]

Doesn't make sense that anything would be stuck into vent slots. Is far fetched to be for balancing but still, I looked into this...



Cutting notches into rotor makes sense for balancing. I'd conclude those things are not for balance----but not saying I'm right.

Does other side look exactly the same---1 vent slot between them and positioned the same way?

[dannobee]

Balancing weight.

[oregon87]

My understanding is balancing weight, as well, from some of the info I was able to find last night. Since I was foolish enough to rip it out of one rotor, it’s probably a good idea to replace the rotors.

[Dpmulvan]

You’re going to need to have those balanced or replaced.

[oregon87]

I’m going with replacements. Ordered a pair of Zimmerman rotors from our host. I’m also going to rebuild the calipers and repack the bearings while I’ve got the brakes disassembled.