The rivets holding the extension to the cast brake drum in my '27 transmission are a little loose. Can I pound them down or do they have to be replaced? Thanks : Bruce
They need to be replaced. Your life might depend on them.
Absolutely agree. Pounding them tight will only hold for a while. I speak from experience.
Sounds like you are talking about the drive plate.
Loose rivets in the drive plate is a symptom of a misaligned "fourth main"/ball cap. This causes the shaft to flex where it is riveted to the plate.
This misalignment can happen over time (such as bending of the crankcase) or due to not properly aligning the cap during an overhaul or rebuild.
I've replaced several brake drums due to cracks, including this '27 drum. Someone had machined the diameter down which weakened the drum so it cracked shortly there after. This was with old style Scandinavia cotton bands, not Kevlar.
It is a lot of work to pull the engine and tear it apart just to replace a cracked drum. By the time you rivet the drum to the hub, face off the rivets on the lathe, clean everything in the parts washer and then start assembling the transmission again you will wonder why in the heck you didn't just buy a new drum.