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-   -   Failed Axle (https://www.v8miata.net/v8-miata-drivetrains-12/failed-axle-3517/)

.boB 07-24-2019 02:02 PM

Failed Axle
 
7 Attachment(s)
I went to the track last week end. We had no end of mechanical difficulties, and only managed to make one timed lap the entire week end. Oh, well, that's how it goes sometimes.

Anyway, I had just passed 3 cars, traveling at about 110-120mph. There was a sudden and significant vibration, and then lost power. The engine was running fine, and I could work the clutch and shifter. But no power to the ground. I figured it had to be a differential or axle. I coasted to a stop in a safe place, and got towed back to the pits.
Attachment 8380
Attachment 8381

Done for the week end.

This week I took it al apart, and found this:
Attachment 8382
Attachment 8383
Attachment 8384

You can see that the axle stub passes through the splined hole, and then is retained from the back side with a nut. The nut had come off, and allowed the axle to slide out of the splines.
Attachment 8385

I purchased these DSS axles through V8R in 2014 as part of the Stage 2 kit. The axles are rated at 600hp. My mild LS6 only makes 435hp. The axles did not break, they just fell apart. I took the other side apart as well. The nut was tight, but did not have any thread locker on it. It does now.

I'll contact DSS today and see if they can send me the correct parts.
Attachment 8386

The C-clip also broke and fell in to the differential. There were a few small bits of metal scattered in there. The gears look good, and I didn't see any marks on them. I'll take the pumpkin to a local shop and have Paul check it out.

I'll let you know how this turns out.

5.0MX5 07-27-2019 12:43 PM

Wow, bad luck for sure. That said I can envision a much different end to the day if enough newly created scrap metal had caused a bearing to fail and/or somehow locked the diff at a most inconvenient moment.

Good Luck!

RR

.boB 08-05-2019 02:21 PM

I called the Drive Shaft Shop a couple weeks ago and ordered the parts I needed. I sent them some pictures so they would know exactly what I needed.

I called them again today. They have no idea what I'm talking about. Sigh. Here we go again.

WolfGT 08-06-2019 08:41 PM

That would royally piss me off. They would not get my business.

.boB 08-07-2019 08:26 AM


Originally Posted by WolfGT (Post 26411)
That would royally piss me off. They would not get my business.

Unfortunately, they're about the only game in town.

WolfGT 08-08-2019 04:32 PM

I assume you mean locally. Because there are plenty of drive shaft businesses that I'm sure could help you out. And if you already spent two weeks going nowhere with these guys, waiting on a shipment from one that gets it done would be time well spent. Then again, I could be wrong on that.

Are those 31 spline? (because I see the stage 2 from V8R can come with either 31 or 28)

movieboy4fun 08-09-2019 12:19 PM

hello .boB
I know that you can get a stub shaft that will fit the 31 spline 8,8 rear and allow the 930 CV joint. I purchased 2 units a while back (9 yrs) for my dune buggy project. The stub shafts were hardened and one piece with no NUT. As to the nut, if I ever built anything with half a nut depth engagement I would never be called back for poor workmanship. Nuts usually need full thread engagement with at least 2 threads sticking past, at least that's how I make sure that high stress mill parts stay together. I would say that is poor workmanship, In my opinion I want to add. I will look through my notes and try and get back with a supplier, they were not cheap, but cheaper than the time I spent cutting the bearing cups off of the 28 spline cobra stub shafts and welding on 930 mounting flanges. I don't really like machining 4340 but I had no choice as I could not find a supplier for 28 spline axles that were affordable, ( since Factory Five is so lame and dropped 28 spline axles). Then I had the whole thing re heat treated and voila, we have 28 spline stub shafts. I finished the setup with floating buggy axles and F150 front CV joints, I think, been a few years and I no longer have the buggy.

update: Opened my mouth too soon with a solution, LOL. It was 9 yrs ago when I did this swap and I am positive I only paid $290.00 US for the pair of 8.8 - 930 stub shafts. I actually got the idea from my 04 M3 set up when I was checking the guibo for cracks. Appears these stub shafts are made of platinum now, best deal I could find was $599.00 US. My father is the gifted welder / metallurgist so items like this I get him to build for me. Apologize for lame info, good luck on your quest.

Good luck with your project.

.boB 08-13-2019 06:10 PM

Still waiting on the parts. Supposed to be here tomorrow. I am hoping they also send me the retainer clips I need. Those things are impossible to find!

.boB 08-15-2019 08:58 AM

Parts arrived yesterday. Everything was ready and waiting. Took about an hour to get it all back together and driving again. Racing on the 24th.


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