Suppose we have a "12 inch" drum.
This particular one is a 3/4 ton truck with Dana 60 floating axle. 12x2-1/2 shoes.
I have a brand new drum I just took out of the box. Shouldn't a new drum be 12.000"
I don't get it as this new drum is measuring out at 12.045, drum marked 12.060 max.
Brand new and only 0.015 to max diameter? I remember having the whole 0.060 from a new drum to "junk" status.
Yes I replaced the battery in my drum mike and recalibrated it. And checked the reading. And recalibrated it and checked again.
I realize that I haven't used my drum mike in a few years since all I work on at the job is 4 wheel disc anymore but cmon now something doesn't seem right. .

No comment? Does anybody else check new parts out of the box? I never used to.
2 of the rusty original ones (I have 2 rear ends I pulled the brakes apart on, hoping to get 2 good ones out of 4 and NOT to have to put Chinese drums on there. But the ones off the original rear end in the truck measured exactly the same as the brand new raybestos drum out of the box ... But from sitting they need "cleaned up" but there isn't enough with 0.015" of play room to try.

I agree that it will be at least "next" brake job before it might be an issue... But I paid for new. I didn't go pull them off at a junkyard or anything...
Another weird thing is that the original ones to the truck measured less than the ones on the other rear end that I have in sawhorses... 12.045 vs 12.110". But the web on the further "shot" ones is definitely thicker than the web on the original ones.
The original is 1983 and I'm 98% sure they are original to the truck because they said "BUDD" on them.
The rear end on sawhorses is out of an identical truck only an 84. Those drums say"CANADA " on them. I'm wondering if they got replaced somewhere along the way... I know alot can happen in 43 years... The only thing else I know about the 84 rear end is that I got it from a guy in Ohio who parted out the truck it came in. All he had left were the motor and trans which is now in (I forgot which) a '33 or '35 Dodge body. And the gas tank which I also brought home.
I don't know anything about that truck. I do know what the 83 has been thru/ has had done to it since 2008.

No idea how the aftermarket companies decide anything these days, EXCEPT to make it as cheap as possible to make. I haven't had a rotor or drum turned in probably 25 years. Buy new, or NOS, or forget it, and hope the quality is good enough to get you down the road for 10k miles or more. This is the world we live in...

Also, I convert everything I have to disc brakes these days. Not including my 1989 B350 van. I will have to think hard about ever replacing rear drums on that thing. Probably just do shoes and hardware and maybe wheel cylinders and leave the drums alone.

Lou

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Home of Slant6-powered fun machines since 1988

I've done exactly what you said on lots of drum brake systems over the years. I do take a grinder and juuuust take off the rust lip on the edge off, put em back on, adjust the star wheels and away they go.
And when I had access to a lathe and a drum or rotor came on with "railroad tracks" from rivet heads being ground off in service, if I could clean one up and just leave some of those 2 grooves behind (which are right in line with the rivets on the new ones anyway, sometimes id resurface the rest and leave those go... In this case I'm completely redoing the truck from the bare frame back up, and the drums and rotors were all "way" shot and out of specs with all I'm spending on this truck in the overall picture the price of new drums won't kill a deal. But I've been thru several situations where I'm saying "that won't be much more" and "that won't cost much". As long as I did such and such I might as well do this too" and it's adding up....
What I DON'T like is buying new parts where the new parts are already 75% "junk" when first taken out of the box.
Would it last the rest of the life this truck is with me? Being a rear drum, probably... But when you spend money on brand new one it shouldn't be that way

Found a pretty lengthy interchange list off of one eBay listing, I punched some of those numbers in the search and found some brembo brand drums for a too good to be true price (less for a pair than anyone else wanted for 1)
They used to be a better brand and I sure didn't know they made drums for these trucks..
Used to be (I think) Italian but I found out like everything else drum and rotor wise now "made in China"... Damn.
Trying not to use any Chinese parts.... This was after I bought a set of centric ones off of RA. ( Also cheaper than most wanted for 1 but not by as much as the brembo ones) I'm guessing that I probably won't use up 1set in the years I have left and this truck has left, but parts for anything aren't getting any easier to get or certainly not better in the QA dept... So probably won't hurt to have a set of spares just in case.

Ok hope someone is still following this. I have something that may be useful
I ended up with 4 more new drums for this truck (for a total of 5) but as a test of QC and to satisfy curiosity it was almost worth it. All came at a "deal" didn't pay retail for any. And because the clock isn't working backwards towards good quality at a reasonable price as long as I have the D250 I don't mind having spares while the gettin is good... I have an extra set of everything pertaining to the brakes and the front suspension even after I replaced everything with new... All brand new but made when QC actually stood for something.
And strangely in this day and age the cheapest ones I have are the best of them.
I got 2 of rock auto's last 3 centric ones they showed as having (they had bendix and I think 1 other option for the 12x2-1/2. None were raybestos in that size.

Then after I punched my card number in for those I found at RA I found some other part numbers for the same thing in other brands that show as "equivalent" in other brands.i can't believe how many times even Mopar changed the PN of this same drum over the years.
Some of those numbers led me back to feebay.
Off of one of the old Mopar numbers I hit on a pair of (I couldn't believe this) a guy who had a pair of brembo brand drums. He has several others listed on eBay as well as 1 more pair of these.
They were too good to be true priced and that even included shipping.
Well the RA sourced centric ones as well as the eBay brembo ones all showed up today.
Next surprise is one of the brembo's is even marked "made in USA". I don't know if they're talking about the drum or the box. One centric stated "made in China" as well as the first raybestos one I got months ago. The other brembo and the 2nd centric aren't marked on either the box or the drum.
In comparing the brembo to the centric there is no comparison. The casting, the machining is very much different between them. In that department the raybestos comes out in the middle of the pack.
The brembo's have a much smoother casting on the outside and the machining is so much better looking. Not to say the centric ones wouldn't be just fine... The brembo's seem heavier as well.
This guy had like 100 (just a guess) different drum and rotor listings. I don't know what else his listings might fit.
I can get the guys user name in eBay if anyone wants it he's out of SC.
I know this post is kind of "dry". But hopefully it helps someone. If he had these he might have some that fit your car...

Oh and the mike readings. This is the best part.
That new raybestos came out of the box at 12.045 already.
The centric ones are much better at 12.012 and 12.014.
The brembo's? 12.005 and 12.007 and have the best finish of all of them.