Topic: 1969 Rear drum blackout

[Bob Gaines]

My S code GT/CS came from the factory with front disc brakes and painted style steel wheels.  I am always trying to improve the restoration to make it absolute Concours.  With all said above, it appears I need to slab black paint on the front rotor hub and brake calipers.  I painted the rear drums with a rattle can, but to be correct, it also appears I need to strip the paint and just slab black paint on them as well, but just the outer facing surface.   Is this correct?  It has never come up when having the car judged at MCA shows.  I show this car in the Concours Trailered Division.

Also, I noticed in all the pictures posted above, I did not see any blue paint on the rear axle hubs.  I believe I brought this up in another post.  Growing up in the San Francisco Bay Area, I remember in the late 60s, early 70s, seeing Ford cars with blue paint on the rear axle hubs.  (I spent a lot of time at a cousin’s auto shop).  I found blue paint in the hubs when restoring my rear axles and duplicated this.   Anyone else find this on un-restored rear axles?  I added a couple of pictures before and after below.

Thanks. Mike

I have only ever found evidence of the black out on the calipers on 69 Shelby's . The thought is because the standard spoke 69/70 Shelby wheel  showed more of the caliper then a magnum type wheel. I don't think it was considered until the 69 production year.Mike, if the point is to be relatively historically correct then your paint on the rear drums is excessive. Just the face was painted if at all. It was painted with a brush and not spray painted so brush strokes should be evident on the edges of the face and to a lesser extent the sides. The typically majority of the sides of the brake drum are cast iron finish.

[Anghelrestorations]

Agree with Bob here....the face of the drum only would have some blackout paint....added on sloppy and with brushed on appearance.  You dont want to paint the entire drum black on the outside.

[jcuprisi]

What was the purpose of machining the edge after the blackout application and what was the function of the groove?

Drum brakes on GM cars had a coil spring around the outer groove. Most likely for Noise Vibration and Harshness (NVH) issues. Kelsey-Hayes and Bendix produced brakes for each of the Big 3 auto manufacturers. The drums were cast by the millions. There was no extra cost involved in having the groove cast in. The spring probably proved ineffective and was dropped to save money.

I have machined many drums in the past. Many castings were off center. The outer diameter was machined to a specific round diameter to avoid wheel interference issues. The manufacturer had no way of knowing what wheels would be attached to the car.

[Toploader]

Thanks for the info.

Drum brakes on GM cars had a coil spring around the outer groove. Most likely for Noise Vibration and Harshness (NVH) issues.

Would make sense. Kind of the way a rubber band is attached to a brake drum when machined on a brake lathe and for the same reasons.

[Wingman]

I’ve searched and looked in several threads but find this one suitable. I have just dissembled my rear brake drums on my 69 Dearborn built (March) Mach 1.
This is a unrestored picture of the drum black out and white markings on the side of the drum.