rear axle taper/threads

[springerpete]

I am writing this for a friends who is not computer oriented.
The drivers side rear wheel/hub will not stay tight on the taper. After driving for 100 or so miles if you jack up the rear of the car you can grab the tire at 3 and 9 and wiggle the wheel. Removing the stud nuts and taking off the wheel the axle nut is loose. Removing the cotter pin and the nut will be only finger tight.
Yes, the key is in place and the key way is not distorted. When he puts the system together he torques the axle nut to 65 lbs. The cotter pin is a very tight fit. Hub nuts are also torqued to proper values. What can you suggest as the problem and what would be a good solution ? Thanks, Bill

[Fullraceflathead]

Normally when torqued correctly to 100lbs it will stay tight. It will be so tight that it will require a puller to break it loose.
Once it becomes loose while driving and un noticed the taper will wear on both the axle and hub. Once this begins to wear the locking effect off the taper is lost.
A new hub may fix this provided the axles taper is still in decent shape. Worse case scenario would be both tapers ruined. This would take a lot of driving on a loose fit to happen. Both hub and axle would have to be replaced in this instance.
If the threads on the axle are starting to strip thus loose nut still coter pinned it is possible to rethread to the next size smaller. I made a video of doing this on my YouTube channel.
I torque my 9/16 threaded axle nuts to 80lbs and have had no problems for over 6 years now. Both of my axles were stripped and loose with the nuts still coter pinned when I bought my 1928 Roadster Pickup.
https://m.youtube.com/playlist?list=...5bcpNJQdDfO5H8

[Patrick L.]

What do the tapers [ hub and axle] look like ? I'm assuming there are no shims. When put together they should be clean and dry. I usually tighten the nut to about 90# and tighten until the cotter fits.



Oops, forgot the no in front of shims, sorry.

[Fullraceflathead]

No shims unless someone added them because the hub rubbed the backing plate.
If you find shims then the taper most likely has some wear. I have shims on my axles to prevent the hubs from rubbing the backing plates.

[Joe K]

Hubs can stretch. In fact I'm of the opinion that they do naturally when used. And sometimes (rarely) the stretch can be permanent. And shims can help alleviate this.

You want the joint "dry" - no lubricant. You want a minimum of 100ft-lbs. Some do 120. You want to set it, then drive for a while then "snug it up" back to 100ft-lbs.

You want a washer (with felt) under that nut - part of the seal/system. And you can check to be sure the nut isn't "bottoming out" as you assemble. An additional washer or shim can help.

Joe K

[springerpete]

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Thank you for your thoughts. I will pass along the information and I'm sure he will take your suggestions. Bill

[katy]

The washer that Joe K mentioned needs to be a hardened washer, not your everyday washer.

[Jim Brierley]

I always re-torque the axle nuts after driving them several miles. I just use an air-wrench so can't give a ft.-lbs number, but they must be very tight.

[DBrer]

If the two tapers are not machined correctly it will be very hard to keep the drum from working loose.