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heavy85

Help broke 240z stub shaft - no spare and have race next weekend

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Like the overly long title says. Last weekend I did some agricultural driving at .. er off the racetrack. Just realized why one of the rear brakes are dragging. 0.1" runout will cause the rotor to rub on the caliper. Imagine that :). Well root cause is a cracked stub shaft. I have no spare stub shaft and last race of the year is next Saturday Oct 1. If anyone would be so kind to sell one or preferrably two 240z rear stub shafts I would much appreciate it. Need them early next week if at all possible so i can install and shim and prep for Saturday. Im in Decatur Illinois 62521.

 

Thanks

Cameron

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You should look for a set of 280Z shafts. They are much stronger than the 240Z ones.

 

Are they really stronger? I know they have more splines but more splines of the same diameter does not necessarily mean stronger. Mine broke where through the wheel / rotor mounting flange where it transitions to pilot the center of the rotor. The shaft and spline area are fine. I've been running these for ~30 days on a racetrack + street miles + several autox + however many miles they had stock when I got them ... behind an LS1. Reason I want to keep 240 is because I'm running 280ZX CV joints so have the companion flanges that match.

 

PS - up until ~7 track days ago I also ran stock half shafts. Only issue is the mounting bolts would loosen VERY often. Never broke anything though.

 

Cameron

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The flange to axle joint is a common failure point for Zs run on a race track. I've lost two on the track. The lateral loads cause flexing at that fusion weld and any kind of surface imperfection becomes a stress riser. The 280Z stub axles have a larger OD shaft, a thicker flange, and generally a better fusion weld at the flange/shaft junction. But stub axles used on a track S30 are an inspection item and should be replaced if there are any small pits or cracks seen in the fusion weld. You should inspect that weld every time you have the wheels off the car.

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Hello all, sorry to raise this topic back up. I recently have the same problem on the road race car. Same separation with 280z stub axles.

Wondering if anyone has tried to improve the strength. I have thought about welding each on both sides. Any experiences? Has anyone switched to billet in order to eliminate the issue?

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There are a few sources for stronger stub axles, and I've also seen a number of people weld stub axles and companion flanges. Anything is possible as long as you're willing to put forth the time and/or money.

 

http://www.modern-motorsports.com/stub-axles.html

 

https://whiteheadperformance.com/product/whp-billet-chromoly-stub-axles-27-spline-datsun-240z-260z-280z/

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anyone have experience racing with the billet axles? Did anyone decide to use the 300M for road racing? They're all pretty expensive vs using the 280z with regular inspection. Broke mine at VIR and trying to decide what to put on the car for the next races.

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anyone have experience racing with the billet axles? Did anyone decide to use the 300M for road racing? They're all pretty expensive vs using the 280z with regular inspection. Broke mine at VIR and trying to decide what to put on the car for the next races.

 

A friend who runs a EP car used the CFR 4 bolt variety and there wasn't any problem.  They broke one too and then changed to the CFR part.  I put one of them in and they looked nice and used good hardware for the studs.

 

Cary

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A possible solution might be a 280ZX axle and flange.  People use the 280ZX CV flange and axle in the 240Z hub so that they can run 280ZX CV shafts.  The axles are 25 spline, they might be a direct swap, or you might have to swap bearings also, or bearings and companion flange.  Not sure.  And the dust shield probably won't work either.  For some reason Nissan went from 25 spline to 27 spine then back to 25 spline.

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Pictures please.  I track mine and would really like to know what to inspect. 

 

I am also weighing the option of upgrading to the billet stub axles.

I'll post a pic when I get it off the car. We had a 110v welder that I was able to tack it so could drive the car on trailer. The welder wasn't powerful enough to penetrate. Give me a few days and I'll post

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I think that all of the info needed is in the thread linked below.  The castings are the same for 280ZXT or 280ZX (CV versus u-joint halfshaft), so the same swap should be possible, I would think.

 

http://www.zhome.com/rnt/FordPower/HalfShaft.html

 

Here's a Hybridz thread with bearing info.  It has the same link in it - http://forums.hybridz.org/topic/103344-280zxt-stub-axle-cv-swap/

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A possible solution might be a 280ZX axle and flange.  People use the 280ZX CV flange and axle in the 240Z hub so that they can run 280ZX CV shafts.  The axles are 25 spline, they might be a direct swap, or you might have to swap bearings also, or bearings and companion flange.  Not sure.  And the dust shield probably won't work either.  For some reason Nissan went from 25 spline to 27 spine then back to 25 spline.

Not going to work. I was pretty sure the 280ZX stub and bearing are the same as the 510, which is smaller than the Z. Just verified that on Timken.com. Z rear wheel bearings are RW116 and RW117. 510 and 280ZX bearing numbers are RW101 and RW125.

 

The ZX stub shafts are smaller. I believe 1/16" smaller diameter.

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Posted (edited)

You're not clear.  Ithink that you're saying the 280ZX axle won't work with a 240Z companion flange.

 

Then a 280ZX u-joint halfshaft companion flange (with the 4 holes) along with the 280ZX axle should work.   As shown in the link.  Basically convert the 240Z axles and flange to a 280Zx axle and flange.

 

Or that guy is completely wrong.  Or the 280ZXT CV casting is a different size than the 280ZX NA casting.

 

Edit - adding some bearing sizes just for fun.  So, there's no good way, apparently, to use the 280ZX axles in a 240Z.  I wonder if that guy just ran loose axles and didn't even know it.  Scary.  I'll have to stop referring to that page.

 

ZX

RW101 - 30mm inner, 62mm outer, 16mm width

RW125 - 30mm inner, 72mm outer, 19mm width

 

Z

RW116 - 1.25" inner, 2.75" outer, 0.6875" width

RW117 - 1.25" inner, 2.75" outer, 0.8661" width

 

Metric Z

RW116 - 31.75mm inner, 69.85mm outer, 17.46mm width

RW117 - 31.75mm inner, 68.85mm outer, 22mm width

 

From the zhome link - 

 

"To make a long story short, I found that the entire ZX Turbo shaft assembly from differential to and including the wheel bearing companion flange that slips over the splines at the wheel axle can be interchanged with the same Z parts. "

Edited by NewZed

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