Rear stub axle just broke when tried to torque nut?

[bluezcrazy]

Hey everyone,

I have been working on replacing my rear wheel bearings for some time now. Got the new bearings and seals in no problem, today brought my Snap-on 1/2 inch torque wrench from work home for the lock nuts. First nut I tried to torque snapped the stub axle off in it when trying to go to 200 ft/lbs. how the heck? I decided to torque the other side with less ft/lbs. and stopped at 170. Anyone else know what happened, torque wrench malfunction?

Bryce

[Zed Head]

They've been known to break in service, apparently. Look down at the bottom of Post #1 (about half-way down the page under Stub Axles) here in JMortensen's thread from Hybridz - http://forums.hybridz.org/index.php/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/

Maybe you just got lucky and yours broke while it was still accessible. Do you have a picture? Broken stuff is always interesting.

[zKars]

There is no way you could break that thing without there being a pre-existing flaw or crack in that axle. Consider yourself lucky you found it this way. Hope your wrench is not the cause...

[Bonzi Lon]

Wow! Your stronger than you thought. I won't be arm wrestling with you.

Look at the broken ends to see if there is any rust from a crack or flaw in the steel, may have to magnify.

I don't have any parts to help you out on this.

Bonzi Lon

[bluezcrazy]

Zed Head and zKars, that makes me feel better. I was just shocked that it broke, and worried about the other breaking the same way. Do you think the 170 ft/lbs. is ok, or should I try it to at least the 183 the manual shows? Thanx for your help.

Bonzi Lon, yeah not many challenge me in an arm wrestle Luckily my 72 parts car is a perfect candidate for being a donor. If I didn't have that car here with the parts I need I would have been alot more angry . It's just going to slow me down considerably. I have to get some other things removed on the parts car before I can remove the stub axles.

Bryce

[jmortensen]

I wouldn't back off on the torque to save the axle. As the others pointed out, if it breaks when the car isn't moving consider that a very lucky thing. Looks like you have drum brakes. If a stub axle breaks and you turn a corner, it is possible to pull the axle straight off the car and lose the wheel.

[Jeff G 78]

Bryce, can you retake the 2nd picture? It's too blurry to determine if there was a previous fracture. Use the macro function on your camera and get really close to the part.

[GreenZZZ]

Too blury to tell, but doesn't look like it has the flat nut peening area at the end of the threads which makes me think its a replacement stub axle, not the original. One possibility is the mechanic that replaced the stub axle put 500 ft lbs on the nut.

Edited March 4, 2012 by GreenZZZ
oops - that's the new nut, not the old one

[jmortensen]

Too blury to tell, but doesn't look like it has the flat nut peening area at the end of the threads which makes me think its a replacement stub axle, not the original. One possibility is the mechanic that replaced the stub axle put 500 ft lbs on the nut.

I see the flats. Why the wild speculation though? These things break at this spot. It's not so unusual as to require a wacky theory about the stub axle or the person who installed it.

[GreenZZZ]

Why the wild speculation though?

It's just what I do... Take something apart and go WTF! How did THAT happen?

Larger View

[bluezcrazy]

Here's another picture, my camera is too old and cheap. It does have the 2 flat spots on the side you guys are talking about. I used my wife's Sony and was able to get a better shot.

Bryce

[John Coffey]

That's a strange looking fracture. Almost looks crystallized in the center. Not like anything I've seen before although it does look like its had a crack for a while.