• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!

    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR2/3/3A Drum break turning specifications

Scotsman

Jedi Hopeful
Country flag
Offline
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
 
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
 
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).
 
Back
Top