Rear Drums

[unklpat]

There has been some discussion lately regarding turning rear drums. People are being told that their drums can't be turned. Where might the shops be getting their info. It seems that the FSM lists the diameter as 9.0 inches, and after some searching, I found someone who said the max "turned" is 9.040, and max wear 9.050. I could not find the max spec in any printed document. If that is true, it doesn't seem like a lot of wear is allowed, and I can't believe Datsun would put such a low spec on max wear. I have a pair turned at just past 9 inches, and there is still .020 left on the steel liner. Does anyone know the actual max turned diameter? Maybe some of our elder statesmen can chime in. Thx Pat

[redroadster]

Most CAR drums the limits are usually about .060- .080 from new on 311 sized drums depends on the thickness to start
, but really quite a bit can be taken off a 311 with no danger of failing , they air on the side of caution because people push the limits but a shop holds to the wear limits
There's a huge difference between a 311 and a full sized sedan , pulling a oversized boat with the family on board on the highway.

[unklpat]

Is there any printed factory spec for max wear? I think shops are looking at the 9.0 inch stock diameter, and saying no to turning. Or where are they getting their max spec? Pat

[itsa68]

Chilton repair book is stating a 9.040" max wear limit for the 510 and 240Z rear drums and some of the 240Z aluminum drums are marked with a 9.055" wear limit labeling.
Just to keep it simple go with 9.060"

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Cheers
Ray B.

[unklpat]

Right, my machine shop told me today, that the industry standard on most drums was .060 wear. Hopefully some of those turned down (get it?) on their requests can get their drums done. I think you'd have better luck at an actual brake shop, than a LAPS. Thx Pat