Stub axle thread damage

[The Rototiller]

these are the threads on a 280z stub axle. are they repairable? please help!!!!!

 

 

 

[JMortensen]

Someone didn't remove the peened section of the nut before they hit it with the impact...

 

Don't worry about it, the portion of the threads you screwed up is behind where the nut actually sits when it's tightened down. Get yourself a thread file and spend an hour or two fixing that (yours do look particularly bad, BTW).

 

Think of it as a learning experience, you'll be prepared for next time. To cut off the peened section of the nut use a Dremel with a cutoff wheel. CAREFULLY cut the the flat part off being cautious not to cut into the stub itself. Takes a while to do, but it saves a lot of thread filing hassle later.

[JMortensen]

This might help you out too. Before you get into anything else, read about it first here: http://www.atlanticz.ca/zclub/techtips/index.html

 

You've pretty much encountered the two biggies. The spindle pins and the stub axle nuts are the things everyone needs help with the first time IME.

[The Rototiller]

jon i did cut the peened part off both nuts. i think on this one i did not cut off enough or there might have been some previous damage to the threads that i might have made worse. the other stub axle nut came off with no damage to the threads.

as far as the spindle pins go. i gave up trying to remove the spindle pins from the 280z control arms. after you told me that the 280z control arms were slightly different from the 240z ones i decided to use the 280z control arms to test out the new tool that i made. i will tackle the 240z spindle pins in about a week. hopefully i will have more luck with the 240z spindle pins because i really want to use the urethane bushings.

[Mikelly]

Snapon sells the metric Dies to rethread them... I ordered a couple.. one for myself and one for Michael O. a while ago. Forgot the part number, but you can order a die from them in the right (I think it is a 20MM) thread and clean them up... Or get a file...

 

Mike

[JMortensen]

A die would work great if you could get it started correctly, but I'd use a file and work backwards on those. If you tried to run a die down them your chances of hitting the remaining threads correctly are slim to none.

[SSflyer]

I cleaned up the threads on one of my axles by cutting an extra nut in half with a Dremel tool, clamping it back together over the good threads, and unscrewing it all the way to the end of the stub axle. Make sense? The threads came out perfect. Just make sure the threads in the nut you're using aren't monked up too.

[v8dats]

cool idea!

[Sean73]

It looks to me like the damage goes way below where the peened part of the nut touches. I wouldn't use it, but maybe a die would clean it up.

 

I got my die from harbor freight, as part of their big $80 metric tap and die kit.

[The Rototiller]

I cleaned up the threads on one of my axles by cutting an extra nut in half with a Dremel tool, clamping it back together over the good threads, and unscrewing it all the way to the end of the stub axle. Make sense? The threads came out perfect. Just make sure the threads in the nut you're using aren't monked up too.

 

your post has given me a idea. i could take a 20mm x 1.50 die and cut it like i have shown in the pic. place it at the base of the threads where i still have a few good ones left. clamp it back together and slowly back it out by hand to repair the threads. i think if i get bottom threads straightened out where the nut rests on the washer i should be ok. ssflyer, what did you use to clamp your nut after you split it? (boy that last sentence could have a whole different meaning if you didnt know what i was refering to)

 

 

 

[Cal Poly Zmanaustin]

You could probably fix it as described. I personally would get another stub axle because I wouldn't want to risk something I wasn't 100% sure would hold under stress. Just my .02.

 

Mark

[blueovalz]

SSflyer's idea is a good one. I used this same method on my treads as well. I wanted to avoid the die because of the removal of material, so I tried the bisected nut first, and it work great. But these (your) threads are mucked up further down the stub than mine were.

[SSflyer]

I used a c-clamp. You'll find there's a sweet spot where it's clamped tight enough to reform the threads but not so tight it's too hard to turn. If you use a regular stub nut, you may want to also cut off the land at the top of the nut to give yourself a little more room.

[johnc]

Sorry, that stub axle is junk. The threads that count are pulled up if you look closely enough. It appears to have been overtorqued when last installed.

[JMortensen]

Overtorqued??? I usually put these things on by sticking my impact gun on 5 and hammering the crap out of it. Torque spec is 180-220 ft lbs or something isn't it? Somebody ate their Wheaties that morning... or used a 3/4" impact on the thing.

 

I see what you guys mean though. Usually these get damaged by the flat part not being ground off but this one looks like the threads are a little mushed all the way down. That's a bummer.

[Hybrid240z]

I agree with John. I wouldn't reuse it in this condition myself, too risky.

[The Rototiller]

anyone have one for sale cheap?

[johnc]

I usually put these things on by sticking my impact gun on 5 and hammering the crap out of it. Torque spec is 180-220 ft lbs or something isn't it?

 

You can do it that way, but the FSM way is:

 

1. Assemble and torque down to the minimum specified torque (181 ft. lb.)

2. Check wheel bearing preload (3.9 inch lb.)

3. Tighten or loosen the wheel bearing lock nut until the specified preload is reached.

 

The last set I did required 220 ft. lbs on one axle and 192 ft. lbs. on the other.

[JMortensen]

This is ringing a bell. Haven't we talked this one out before? Maybe on WCZR?

 

Changing the torque on the nut shouldn't really change the drag. The drag is set by the size of the spacer. The spacer is something like .120 thick. It's pretty damn thick. So changing the nut torque would have to either crush the spacer (not likely) or deform the inner race of the bearing (not good) in order to change the preload on the bearings as far as I can tell.

 

Adjusting the preload by adjusting the torque on the nut is akin to setting the pinion bearing preload in a diff with a crush sleeve.

 

In this case where a solid spacer is used it works out in much the same way as a diff with no crush sleeve, but a solid spacer in between the pinion bearings instead. It doesn't matter if you have 80 or 180 ft lbs on the pinion nut until it actually causes either the spacer or the races on the bearings to crush. Until that point changing the pinion nut torque isn't going to change anything at all on the pinion bearing preload. When you want to change the preload on a pinion with a solid spacer, you need to add or subtract shims from between the bearings to do so.

 

Since these are ball bearings and not tapered rollers, adjusting preload seems like a really bad idea, because unlike tapered rollers where you can push the cup and cone together to get a proper fit, ball bearings don't take a side load that well. So it seems to me that what you would really want is the bearings to be tight in the housing and have 0 preload, and for ALL of the drag to come from the wheel bearing seal on the shaft + whatever drag a couple of greased ball bearings have.

 

At least that's the way I understand it to work. Maybe I'm wrong. I suppose the way to find out would be to install a set of bearings on a stub OUT of the strut housing, then torque the nut to 180 and measure the distance between the races, then increase the torque and measure again.

[johnc]

I just do what the FSM says to do. There's also a washer and nut/bolt stretch to take into account and the FSM calls the 3.9 inch lb. setting "bearing preload." BTW... 3.9 inch lbs. isn't very much. I actually have to borrow a neighbor's digital inch lb. torque wrench and set it to 10 inch lbs. - I'm a little over spec. Someone also said to use a fishing scale and hook it to a wheel stud. If it takes a 1/8 pound to pull it, then the setting is supposedly correct.