Drum install

V

Vern1030

Member
Is there any tricks to keeping the key in the key way when installing the drum on the rear axle. That Cast iron drum is heavy.
 
Just make sure that the part of the key that has a slant on one edge goes in first towards the backing plate. It will almost bottom out where the end of the axle housing begins. You can actually see the keyway groove in the axle sloping upwards here to mate with the angle of the key. Tap the key downward into place in its groove or use a vise grips to seat it. Should the drum not go onto the axle with a little persuasion, back off the brake shoe adjustment via the wedge. The drum WILL go onto the axle with some "convincing".
Marshall
 
A little background on what Marshall said: The curved section in the keyway in the axle is there because of the tool that was used to cut the keyway. The bevel at one end of the key is there to accommodate the curved section.

Turn the axle around so the the keyway is on the top. Gravity will keep the key in place if the keyway and/or key are worn a little. The key is supposed to be a snug fit in the keyway.

The key is a backup in case the nut comes loose. It is not designed to transmit the torque. The matching taper in the hub and the axle are what transmits the torque. I torque my nut to 100 foot-pounds but many people on the Barn torque theirs to 50. The torque should be checked after the first 100 miles and thereafter at regular intervals. I check my torque when I do the spring greasing of the car but it all depends on how much driving you do.
 
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In my early days learning about Model A's, I neglected to put the keys back in the axles after doing something inside the rear drums. After tightening the outer nuts, I tried to drive the car forwards. It wouldn't budge in gear, forward or reverse. I could hear the transmission working in 1st gear and hear scraping revolving sounds come from the rear. But there was no movement. I happened to glance at the newspaper on the floor where I had lain the parts removed while taking off the drums. There were the two axle keys, greasy and camouflaged on top of a black and white photo in the paper. That's why I had overlooked them. The axles had been spinning inside the hubs, which is the noise I heard coming from the rear. Going through the motions again, I replaced the keys and the car moved as it is supposed to. Lesson learned: Don't forget to re-install the hub keys!
Perhaps the outer nuts were not tight enough to drive the drums far enough up the axle, but I should think the keys ARE necessary to turn the hubs without the axles slipping inside them, as happened to me.
Marshall
 
Marshall, Please repeat the test described in your post above. This time tighten the nuts to 100 foot pounds and use degreased axles and hubs.
 
The key should fit quite snugly in the groove in the axle. If your key won't stay in place when you're sliding the drum on, I'd guess your axle groove is buggered up. This could have happened over time if the rear axle nut was loose allowing the hub to move on the axle.
 
Will N said:
If your key won't stay in place when you're sliding the drum on
Click to expand...

You could try taking a centre punch and put a dimple or 2 alongside the keyway in the axle, don't overdo it, just enough to snug up the key.
 
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