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M2 Z31 Short shaft issue


SUNNY Z

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I hate to be the bad news bear, but rawr. I took the axles apart to put new CV boots on, and found this. :huh:

 

2012-08-11_12-32-56_696.jpg

 

Both ends....

 

2012-08-11_12-38-38_468.jpg

 

This was the passenger side. 275 street tires, on the street.....

 

ALSO, the driver's side axle (stock Z31T) was completely fine. Splines had NO issues on either end......

 

On the next "unbreakable" solution i guess.

Edited by SUNNY Z
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Holy Shnapz! this doesn't look too bueno. Stock shaft was fine but aftermarket shaft got twisted? :o you think one wheel was pushing more power than the other regardless of the lsd? (bad clutches?)

Hope noone else has had any issues.

 

Any way, any 411 on the recalled/ updated shafts arrival date? I'm planning on taking my pair of correct lengths shafts when they arrive to a fabricator down in Mexico to get a set of clones done which according to him are made from tempered metal used on SEMI-truck shafts. hahahaha Good luck breaking these bad boys lmao "Can't be too careful now a days right :D "

 

 

I hate to be the bad news bear, but rawr. I took the axles apart to put new CV boots on, and found this. :huh:

 

2012-08-11_12-32-56_696.jpg

 

Both ends....

 

2012-08-11_12-38-38_468.jpg

 

This was the passenger side. 275 street tires, on the street.....

 

ALSO, the driver's side axle (stock Z31T) was completely fine. Splines had NO issues on either end......

 

On the next "unbreakable" solution i guess.

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Could this be a materials issue? Kinda like some 1018 got mixed in with the 4140 or the 4140 didn't get heat treated/hardened properly.

 

1018 Mild Steel = 54 KSI yield

4140, Annealed = 65 KSI yield

4140, heat treated and tempered = 152 KSI yield

 

A hardness test will tell you what you got.

Edited by rossman
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Sorry it took so long, guys. It has been raining cats and dogs for the past 2 weeks and I had to bale, I mean mow, my yard or the snakes were gonna get me.

 

I only inspected the outer CV of each side. Everything looks great WITHOUT any twisting of the axle splines. Added more moly grease and buttoned it back up. As a side note, my axles are doing fine using hose clamps to secure the boots-makes it a lot easier to do things like adjust boots and inspect. Another point of interest has to do with alignment and axle length: I have adjustable rear LCAs to keep from having tons of camber with a lowered car. In order to get the track and camber even on both sides, the driver side LCA is adjusted longer than the passenger side after 4-wheel alignment. You can see this difference in the placement of the CV cage with the CV "case" when I pull back the CV boot. Both sides of mine appear to be fully engaged within the CV case and I don't anticipate having trouble with them being too long or too short. Eager to get back to the track with confidence. For folks new to the discussion, I am drag racing as much as I can with M2's shortened CV axle shafts. My car has a stock LS2/T56/stock clutch with 3.90 R200 CLSD with extra clutches, shimmed to 60# breakaway on bias ply wrinkle-wall slicks (MT ET Drag 26X8.5X15). Doing moderate burn-outs with line-lock, warming tires until I hear the rpms drop off a bit, then rolling out of burn-out and up to stage. I'm leaving the line at modest rpms (maybe 2,000) and lifting off throttle during shifts. Fastest 1/8th-mile time has been 7.29 at 96mph, but averaging about 7.5 at 94mph due to inexperienced driver. Best 60' was 1.7 but it was purely by accident. 20-something runs on this kit and drivetrain is doing fine.

post-5903-053931600 1345341344_thumb.jpg

post-5903-052955200 1345341381_thumb.jpg

Edited by RebekahsZ
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Can I just add that the pics SunnyZ posted show a polished axle, mine didnt look like that. Not fitted mine yet so can't comment on how they've held up.

 

Sunny did you polish yours or is that how they came?

Edited by 24OZ
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Ditto here, mine were practically black before I cleaned them and painted them. My money says the machinist failed to heat treat SUNNY's axles, or used an incorrect alloy. Lets give M2 a chance to look into it. I think if you got the blackened ones, you are probably going to be ok.

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It could be that the machinist decided to lap or turn down the OD this go round.

 

Assuming there is no lot traceability then a hardness or tensile test is required to determine if the heat treat is correct.

Edited by rossman
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I really don't know what I'm talking about. I'll try to stop speculating until M2 checks into it. I'm glad a few folks are willing to stick their necks out to get specialty parts like this (and the LS longtube headers) made. The low volume of sales hardly makes it a big profit opportunity. All the guys building parts for the Z-car must do it for the love of it.

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