Depends what wheels the car was built with. If it was a hub cap car, they are bare cast. If it was a a sport wheel car, the outer face of the drum was painted black, to be seen through the wheel
I realize thats what the assembly manual says, but I have proof that it didn't always happen that way. My '71 GS came with steel wheels and hub caps and the brake drums are definately black. Still there after 30+ years. This is a Flint car built in 2/71.
Well mine are black I agree with darrenkp that what the assembly manual says and what actually happened on the assembly line won't always match. In a perfect world the answer to your question would be exatly what Nicholas said. But think for a moment about being a person in the factory, it you actually paint just the drums that are supposed to be painted, you would actually have to use you brain and read the build sheet (or something to designate the wheel type), but you can turn your brain off and just paint every the drums on every car, doesn't matter to the painter if he wastes a few oz. of paint on each car. That being said, here is a picture of a rear drum on a 25,300 mile Skylark. When I got it in October, it had never even had the drums off the car, not even for a brake inspection, this is known because the locking washers that hold the drum on while the chassis traveled down the assembly line without tires are all still on the car. There are 2 washers on each of the drums of this car. I had to bend/break them to get them off to check the brakes. The car has steel wheels and full wheelcovers. All four drums on the car were painted shiny/glossy black on the vertical surfaces of the drums. each axle had 1 lug stud that had the end painted yellow (it appears white in the photo). So my opinion is that I would painted the drum cast iron first and then paint the face if the drum lightly with semi-gloss to glossy paint. Hope this helps.
Earlier today I was looking at a pretty clean and rust free original 71 rear end I have sitting here. It still has some black paint on the brake lines, so apparently the complete rear end with the drums installed was painted as an assembly. This rear was out of a 71 GS 350 assembled at the Freemont plant around 10-71 with the 15x7 rallye wheel option. Tim
While we're on the topic of brake drums ..... Does anyone here know how to decipher the date code on drums? (and any other casting codes, for that matter)
Many of the cast parts such as brake drums, engine blocks, cylinder heads, & intake manifolds share the same casting date method. The letter signifies the month and the number signifies the day of the month. A few examples would be : D 9 = April 9th, F 18 = June 18th. The letter "I" was not used to signify a month. A = January B = Febuary C = March D = April E = May F = June G = July H = August J = September K = October L = November M = December
Thanks for the date code info, StratoBlue72. That was the scheme I expected. I was hoping a year was encoded on them somewhere, too. No such luck? Or maybe the Kelsey Hayes part number can tell me what year: KH-74439. I'm trying to authenticate the drums on my Oldsmobile. Probably a fat chance after all these years, but almost everything else on this car is original.
