Cast Iron Drums & Hubs

V

Vic in E-TN

Well-known member
Last week I found a pile of old drums and hubs. I carefully pressed out the studs. I put the rear hubs on a cut off rear axle chucked in a 3 jaw chuck. The runout of the axle was 0.002.

#1 0.000, 0.000, +0.003, 0.010, 0.006
#2 0.000, +0.010, +0.010, 0.018, 0.005

I gave the second a few whacks with a hammer.
#2 0.000, -0.001, +0.003, +0.002, +0.006

My questions - What is the allowable rear hub runout prior to installing the new drum? Is the same number for the front drum?

Is it acceptable to true the hub by shaving a few thous off instead?

How can one mount the front hubs on to an old front spindle? I would use new races on the hubs and switch the bearings.

Thanks for your help.

Vic
 
I do not believe it really matters what the axle to rear hub run out would be.

The rear hubs ride on the bearing and the axle floats. The question is how much wear do you have on the hub and the axle end? That gives an offset that needs to be accounted for when determining the center of the shoes. Keep in mind most of the wear seems to be deep in the rear hub bearing surface.

When you cut the front or rear drum you do it based on the centers of the bearings. After all that is were the center of the brakes will need to be. The machine I use has the center for the front based on the two bearings. The rear has a plug that goes in the bearing hole.

I check and did not find the hubs off much more than a thou or two when mounted in the brake drum cutting machine.

When I was done I checked the front hub on a spindle. The drums had maybe .001" out of round. I found the powder coat build up on the wheel to drum contact surfaces could take the drum out of round by .018" or so.
 
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