I decided to replace out a noisy front wheel bearing /hub assembly on my 2011 G37x Sedan today.

All went smoothly until I attempted to slide the axle spindle out of the bearing/hub. It wouldn't budge. I tried tapping it with a rubber hammer, then a heavier hammer. I thought I was being careful not to damage any threads. However, once I finally got it out, replaced the assembly and went to put the axle nut back on, it didn't go smoothly. I thought, it's a big (32mm) nut. Big nut means more resistance, right? Nope! It shouldn't have resistance and I should have stopped there and taken my time.

Instead, I was rushing a bit and I got about 1 turn by hand, then a grabbed the socket wrench and it seemed ok. Couple turns then switched to impact and... Yeah, the nut stopped around the cotter pin hole and was barely spinning. I had cross-threaded the nut, but looked like the axle was fine.

​​​​​Well, I'm only going to need a new nut I thought. Upon closer inspection, it looks like thr first 8 or 9 threads of the axle are slightly squished (see picture) and they are definitely different than they used to be, so I tried the back side of the axle nut on another axle and it spun on fine. So, I tried filing down the first thread or so, to see if the back side of the nut would spin on but no such luck.

I measured and it looks like the new axle nut (which I don't yet have) will have enough threads to hold the axle in place fine if I filed everything down all the way up to the inside of the cotter pin hole. Is that the route you would take? A new axle doesn't look too expensive but normally anything more complex than brakes is outside of my comfort zone...

This is a pretty significant road block for me and was hoping to get some input from the community.

Thanks in advance.

 

You could try chasing the axle threads with a chasing kit. I seen them sold for CV axle threads. Apply a small amount of tapping/cutting oil on the die chaser and go slow a few turns back off and repeat. Though if the threads are severally damaged this probably won't be an option.

And if your looking to repair the nut, it would be a chasing tap, though just going to throw this out there. FSM calls for replacing of the axle nuts and cotter pins every time they are removed.

 

Just finished cleaning up the threads (very carefully) with a rotary thread file like the picture below, and I'm happy to report that I'm able to spin the back side of the but on now. I happened to have a mini dremel made for hobby-type stuff and it really allows great control for an intricate job like that.



Fingers crossed that it works once I get the new nut!

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That is great news, nice work! If the threads were a real mess a thread chaser in the future could work too I believe. Hope everything works out.

 

New nut went on as smooth as butter. Dodged a bullet there! Highly recommend the rotary thread file for anyone with squished (but not completely stripped) threads.

 

Excellent!