Broke an axle

What I do is torque down to a lower number - say 150, drive it a bit, retorque again to 200, drive it a bit and then retorque it again. When I say "a bit" I'm talking just a few miles.

I will say, every time I take my big ole' torque wrench and go to 205, I'm gritting my teeth, making funny faces and praying to God to "just let me torque this one more time . . . please".

It is kind of a "sphincter snapper" to put that much torque on the axle thread. Many bad thoughts go through my mind - many! :eek::eek:


Dale ..... I think you have a good, well-thought-out and reasonable process going there. I like sneaking-up on settings and adjustments. I understand the "just one more time ... please" philosophy. Still, every time one of our members talks about "HOW EASY" his hubs came off, I shudder to think about the condition of his axles. EVERYONE needs to take a few moments to try to understand the physics of how a 'tapered-fit' actually works. That tapered fit is what is meant to drive your Ford down the road. It surely ain't that key and keyway.

Coop

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how come early plymouth dodge axle don,t brake . there tapered. but the bearing is mounted on the axle before the taper the axle runs true. i don,t care if you have king knog tighen the nut if the housing is worn it will brake again
 
how come early plymouth dodge axle don,t brake . there tapered. but the bearing is mounted on the axle before the taper the axle runs true. i don,t care if you have king knog tighen the nut if the housing is worn it will brake again

That is a good point - if there is slop on the outer bearing surface, then the hub is moving around and not running true. Then as you hit bumps, load/unload it, go around corners, etc.. - there is stress put on the axle itself.

I'd never thought about that - key point!
 
do you think ford would have spent the cost to have key ways cut in over 40.000.000 axles & drums. if they were not needed. model t to 1948. if ford could save a dime he would do it. plus the price of the key thats four fey ways & two keys for every car he made. proubly over 40.000.000
 
Finished, oiled up, ran, set went back and put another couple of pumps in. Will try to post the broke axle ends tomorrow after I clean the mess up and sort tools.
 
Here is the axle
 

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A keyway break, the most common by far.
Jim, please show us the taper.

Alan ..... I believe you're seeing the tapered piece on the left, with the crack just outside the inner end of the keyway. Look closely and you can make-out the keyway in each piece. Right piece is full size axle with inner end of keyway obvious at top.

Coop


515011
 
The keyway looks pretty well wallowed out, evidence that the hub, due to insufficient torque, has been getting driven via the key, with subsequent wear to both key and keyways.
 
Yeah, I would suspect that the hub was nowhere near tight enough on the taper and/or it had poor fitment on the tapered surfaces.

As Brian noted, this causes the key to drive the hub and not the taper surface - which can cause a break just like this. Also, looks like it was cracked for a while before it finally snapped.

Torque those hubs boys - to 205 lbs . . . and if you need a bigger Torque wrench, go buy one! :D (that cheap bend-beam bar torque wrench that most of us "grew up with" won't cut it!)
 
Coop, I see the keyway. I asked to see the taper. Can you see the taper? I think not.

No, I can't see the TAPER on the tapered piece itself, but that is the tapered piece of the axle on the left in picture. It obviously broke about 1/2" or so outboard of the inner end of the keyway. Clear as mud here in Texas. I take it that you'd like to see a side shot of the tapered piece, yeah?

Coop

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Axle was tight in the hub when I pulled the wheel and hub off the rear end. Keyway may have been worn but I had to drive the stub out with a knocker nut and 8 lb sledge hammer. Here are the pics.
 

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Alan ..... I believe you're seeing the tapered piece on the left, with the crack just outside the inner end of the keyway. Look closely and you can make-out the keyway in each piece. Right piece is full size axle with inner end of keyway obvious at top.

Coop


515011
The discoloration (rusty looking) at break looks like a flaw.
 
@Tony, NY
The discoloration is typical of an old crack, just now giving way with the fresh area cracking all the way. As pointed out previously, the keyway being mangled is evidence that the key itself was the driving force, exerting tremendous stress at the inner end of the keyway. The very rough condition of the taper further confirms the cause of failure.
 
This is the typical breaking point on most every early Ford axle that I've seen broken in the years I've been playing with these old Fords. I also have some axles that I removed from rears I bought to salvage parts from that have visible cracks just starting at that same point of failure. I have to agree with the folks here who are saying most of these axle failures are a direct result of not having the axle nut torqued to the correct specification.
 

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