I had a loose stub axle so I took both sides out. Found two different axles in the car! The one on the left is stamped "J15" and has the backing plate for the lugs while the one on the right is stamped "F15" and has no backing plate. The one on the left had an unpeened nut at about 40 ft lbs of torque. The one on the right was the normal bear to loosen up after dremel-ing out the peened portion of the nut. The one on the right almost has too little rust...

It gets worse, the one on the left had the threads shaved! There was no apparent use of lock-tight on the retaining nut. The spline count is the same on both axles as the flange which hooks to the half shaft are interchangeable.

I have bigger images on my server http://www.lee-thompson.com/Z/StubAxle/ but the bandwidth is slowww.. I have 200K, 2M and 8M versions of the images.

Two questions.

1. Is the shaved thread axle useable with locktight on the retaining nut?
   
2. Where did these axles come from as they are differnt? 260Z??? Its been reported that the spline count is different for 280Z stub axles.
   

Thanks in advance for your advice

If you take the nut off without first removing the peened portion, you will take all the threads off with it. Then you can either spend hours with a thread file trying to get a semblance of threads back, or just grind them off. What this looks like to me is someone went to change the wheel bearings, didn't cut the peened part of the nuts off. One was so bad that they replaced the stub axle, the other wasn't as bad so they just ground off the damaged part of the threads.

Is it usable? Well, the issue is how many threads are you going to have engaged when you put the new nuts on. I would suggest that it probably is, but if you wanted to swap out to another set of stub axles, they shouldn't be hard to find. The stub axle spline count on a 240 is 25, 280 is 27 and I think there is a weird 260 one too, but if you're in doubt just count the splines and that will tell you what you have.

  jmortensen said:

What this looks like to me is someone went to change the wheel bearings, didn't cut the peened part of the nuts off. One was so bad that they replaced the stub axle, the other wasn't as bad so they just ground off the damaged part of the threads.

Thanks Jon. Sounds about right. Car has 300K miles so I'm probably putting the 3rd or 4th set of bearings in. Do you know if the 240's typically have the backing plate? The backing plate shows in the microfilm.

Anyone know anything about the F15/J15 stamping and what that means?

I personally would'nt use the shaved stub axle again especially as the PO obviously didn't have much faith in it at 40lbs torque (should be around 190lbs). Yes all 240's have the backing plate. I guess the markings perhaps refer to the spacer required between the bearings but I would'nt be certain.

Edited January 1, 201015 yr by Nigel1943

  Nigel1943 said:

I personally would'nt use the shaved stub axle again

Thanks Nigil. Z barn has strut tubes for $75. That sounds cheap to me. I'll call and see if it includes the axle. With new lug nuts I'll end up with 2 backing plates that way.

  Nigel1943 said:

PO obviously didn't have much faith in it at 40lbs torque (should be around 190lbs).

I think it was torqued correctly and then loosened. I had a Z shop put in axle bearings around '90 or '91 as I didn't have the accumulations of tool like I have now. I bought the car in late 80's and have been working on it since something like '82. I'm sure the Z mechanic put ~190 ft lbs on it as its been running fine for 18 years. I'm assuming the nut back off to 40 as it didn't have peening or lock-tight on the nut. It probably backed off at the track when I blew the motor up!! Will never know who shaved the axle...

Happy New Year!

Edited January 1, 201015 yr by GreenZZZ
spelling

Later 280Z replacement OEM 27 spline stub axles do not have the sheet metal backing plate. If the stub axle nut was torqued properly and then backed off, there's a problem with the threads on the axle or the nut.

Checked my spare stub axles. They all have different numbers stamped on them.

Decided to go with aftermarket stub axle bearings... They appear to be commonly used throwout bearings. The Nissan stock bearings shot up in price pretty badly recently and Motorsport followed (something like $60.00 for the outer bearing alone). BlackDragon sells the inner/outer and seal for $50.00 per side. This is what is in the kit. Any good/bad/ugly on the aftermarket stub axle bearings? Beck/Arnley makes pretty good stuff from my experience. Don't know RHP...

http://www.classiczcars.com/photopost/showphoto.php?photo=32788&ppuser=14083

Edited January 12, 201015 yr by GreenZZZ
spelling

For what it is worth, the backing plate is nothing but a dust/mud shield for the outer bearing. That bearing has a full seal to prevent the elements getting to get anyway. The shield isn't needed.

  GreenZZZ said:

Decided to go with aftermarket stub axle bearings... They appear to be commonly used throwout bearings. The Nissan stock bearings shot up in price pretty badly recently and Motorsport followed (something like $60.00 for the outer bearing alone). BlackDragon sells the inner/outer and seal for $50.00 per side. This is what is in the kit. Any good/bad/ugly on the aftermarket stub axle bearings? Beck/Arnley makes pretty good stuff from my experience. Don't know RHP...

I got Koyo bearings in a Federal/Mogul box last time I ordered them, and I think they are a proprietary bearing not commonly used in other applications. They are definitely not a throwout bearing, they're not designed for that kind of thrust. What is the name on the bearing itself? Made in Japan?

  jmortensen said:

What is the name on the bearing itself? Made in Japan?

Outer - "JAPAN HX" "NTN" "SXD6A52C4"

Inner - "RHP" "ENGLAND" "LJ1_1/4J" "E"

The Japanese bearing, the first, third, and fourth characters are alittle blury. Could be "8X08A52C4" for instance...

NTN makes some of the stock bearings for Nissan as I recall, so that one should be good quality. Not sure about the British bearing, but I can say that it probably has bad teeth.