So... Lemme get this straight. There is a gasket between the wheel cylinder and the backing plate on some drum-brake cars?
On my very original '64 Dart, there were definitely no gaskets, though there was a foam one between the M/C and the firewall (which makes sense because of air leaks, oil smells, drafts, etc.).
I have also never seen one on any of the GMs I've messed with since the '70s, or any flathead Ferds (or on a few of those "Mustang/Capri pooboxes I worked on years ago).
Did they start using these gaskets in any particular year or model series?
What was the purpose? You're pretty much separating one "outside" space from another one. Drums are not waterproof, and the wheel cylinders usually set in pretty tightly to their holes in the backing plates. If anything, I'd be afraid a gasket would thermally isolate the cylinder just a little bit, which could increase brake fade.
I'd just put it together without, although that might make me a bad person.
- Eric
