Re: 1804-5-7-8 Rear Brake Drums

Posted by Joe Santana On 2020/2/21 9:43:28

I just love talking to myself because I am so interesting. Turns out Packard Didn't stamp the tolerances on prewar brake drums. They cast a number on the hub, but this number is not the part number of the hub and drum assembly.

So the rule is, whatever the original inside diameter of the drum, in my case 12", turning these .10" over to 12.100 is the maximum legal limit. A shop is not allowed to mount drums over that or they may be liable if there is an accident due to brake failure.

And when they are under that maximum, a minimum of .030" should be left because the shoes will wear that much.

It might be tough to find the above hub/drum assemblies NOS. If you can find the correct hub, in my case with large axles 311.81, and a drum of the correct inside diameter (12") and depth (2-1/2"), they can be riveted together.

So a set of two rear hub/drum assemblies (#333931) machined to 12.040, 2 wheel cylinders, 4 riveted brake shoes, springs, washers are coming from Jeff Adkins, Moose Motors, Pengrove CA. Moose specializes in brake parts for all older cars, especially Packards, with many other parts for Packard. The shop should have them early next week.