Just finished up replacing rotors, calipers, lines etc on the front brakes which a PO had upgraded to 70's era 5-lug disks. Got parts for a '77 and they worked just fine.
Now I'm getting started on the drums in the rear which look like they've also been swapped at some point to 5-lugs. I don't know if the PO used parts from the same source as the front or not, so I'm looking for advice on what parts I need to be looking for to do a rebuild on the hardware.
The markings on the front of the drums are:
3989541
MAX DIA 11.09
A search for that number pulls up an eBay listing for
67-72 CHEVY TRUCK NOS Rear Brake Drums 3989541. Since that's the only result, besides a posting here about mismatching drums on a '71, I wanted to see if anyone has any further info on these.
Here are some pictures:
![](https://imgur.com/5K4aBlR.jpg)
5-lug drum on rear-end.
![](https://imgur.com/Mvf8RhQ.jpg)
Markings on 5-lug drum on rear-end, "3989541". Also has marked, "MAX DIA 11.09"
![](https://imgur.com/c9bzc8b.jpg)
5-lug drum heat side heat sinks on rear-end.
![](https://imgur.com/zG1FIHD.jpg)
Inner plate on rear drums.
![](https://imgur.com/aFZAfRc.jpg)
Upper inner plate on rear drums.
![](https://imgur.com/dpo7N3C.jpg)
Lower inner plate on rear drums.
![](https://imgur.com/chx7wZ8.jpg)
Brake pads in rear drums.
![](https://imgur.com/QmfwusC.jpg)
Inner hardware on rear drums (1).
![](https://imgur.com/dKKe6Sl.jpg)
Inner hardware on rear drums (2).
Thanks.