TR2/3/3A Drum break turning specifications

[Scotsman]

What are the specifications for the rear TR3a and 4a break drums with regards to having them turned? I can not find anything on this in the workshop manuals for either car.
Mine are out-of-round. When trying to adjust the back breaks the wheels turns freely and then will catch on the shoes. This results in not as firm breaking as I would like on the first touch of the pedal (yes I have bled the breaks).

Thanks,

Richard

 

[charleyf]

Richard,
The only discussion that I can remember on this subject really had to do with how thin the brake drum can be after getting them turned. So a brake drum should only be turned so far before it is to thin to be safe. I would have to guess that any good auto machine shop should be able to determine that for you without having a specific thickness presented to them.
Charley

 

[Geo Hahn]

When I had a set turned the shop examined them expecting to find a maximum diameter cast on them. Of course there was no such thing.

They didn't want to do it but I looked up some generic numbers and returned with that info and they agreed. Sorry, I do not know what I found (been quite a few years now) might have been 10.1".

Your options may be limited if the drums have be turned previously (which many have by this point in time).