patsmx5

iTrader: (16)

It flies on the big end when it spools. It was low 400whp tonight since boost was down. When I got it to spool I broke a MSM axle, I don't know of ANYONE who'd done that.

patsmx5

iTrader: (16)

Also anyone know if Autozone axles are good? They offer a MSM axle for 200 + core, with a lifetime warranty... Dunno if they are crap or good though.

18psi

iTrader: (76)

if they have lifetime warranty I'd definitely give em a shot.

that way when you snap them you can keep getting new ones

aidandj

iTrader: (5)

MSM axles are somewhat rare. I'm surprised they have them.

Try repacking them with good grease.

aidandj

iTrader: (5)

Wait. It looks like you stripped the hub or something?

Show us disassembled pictures. The outer end of an MSM axle is the same as a non-msm I think. You .might be able to rebuild

Joe Perez

iTrader: (8)

Interestingly, we just had that exact conversation: https://www.miataturbo.net/general-m...t-axles-87914/

The TL;DR version is that the axles seem to be fine mechanically, but have a high rate of failure as the rebuilders seem to use only a tiny amount of low-quality grease. Thus, you can probably use a reman axle, but before installing it you should dismantle both joints, clean them and the inside of the boots thoroughly until grease-free, and then re-assemble them with a generous quantity of whatever grease your religious preferences tell you is best (eg: Redline CV-2, Amsoil Dominator, or SWEPCO 101.)


And yeah, I'm curious to know what the exact failure mode was here, and whether the hub survived it.

patsmx5

iTrader: (16)

Nobody in the world apparently actually has reman axles for sale for this.

I don't think the outers are the same, are they? If so, I have two old axles with good outers.

Joe Perez

iTrader: (8)

Only place I know of that carries MSM axles right now is Rosenthal, and they're $500: SHAFT(R),DRIVE-RR (MA03-25-50X) - $494.95 - MA032550X


So far as I know, the outers are the same between MSM and non-MSM inasmuch as how the outer stub axle interfaces with the hub; only the inners are different in that regard. I'm not sure about the OD of the axle shaft itself, or whether the interface between the axle shaft and the outer CV is different.


Waiting to see pics of the disassembled axle and hub.

good2go

iTrader: (2)

Mazda SHAFT(R),DRIVE-RR MA03 25 50X at PartsVP.com

#MA032550X: CV Axle Assembly

SHAFT RIGHT (R), DRIVE - REAR (RR). REAR DRIVE SHAFT for 2004 Mazda Miata. #MA032550X

All three of those are cheaper still, and they all let you put them in the cart, so maybe they have them in stock too. Still crazy expensive though.

patsmx5

iTrader: (16)

Will disasemble shortly. Thank you a lot Joe for your help, you just found a PN and link to buy something I couldn't find the last 2 hours.

I'll tear it down and see if it's the same as a regular axle on that part. And see what damage I have.

Shortpersonbk

The Driveshaft Shop | MAZDA 1995-2005 MIATA 400 HP Direct Bolt-In Axles - Mazda - Import Axles

Joe Perez

iTrader: (8)

These won't be compatible with Pat's car. He's using an MSM differential, which has a larger receptacle for the splined portion of the inner CV stub shaft than the regular diffs. MSM diffs and MSM axles must go together as a set.

I'm sure that any competent driveshaft shop could fabricate an MSM-compatible axle, but it looks like the part that broke on Pat's car is in the vicinity of the hub shaft, and it's unlikely you could meaningfully strengthen this part of the axle while retaining compatibility with the stock hub.


Worst-case, he'd need something like Boss Frog's "Level 3" axle kit, which includes aftermarket hubs, though of course the inner shafts would have to be custom to fit his diff.


Far too early to be bench-spending money until Pat takes the hub apart and figures out what broke.

pdexta

iTrader: (17)

Looking at his slips next to what I ran he's got my 11.68 pass covered by .3 sec and 3 mph through the 1/8th.

I wouldn't bet against it dipping into the 10's @ 130 as it sits (minus the exploded axle of course). I can't wait to see what it'll do once all the little issues are ironed out.

patsmx5

iTrader: (16)

Yeap. The best part is, I wasn't running full power either, though that's kind of obvious by the trap speeds. This was 32 PSI, and not hitting full boost till 3rd. 80% duty cycle on main injectors.

36-38 PSI gets me to 100% duty cycle which is where it makes the most power of course.

Going to tear into it right now. Will post pics when it's apart.

18psi

iTrader: (76)

Yeah the car is hauling the mail, I'm just being conservative with the bench racer math

nitrodann

I cannot give you enough cats dude.

Joe Perez

iTrader: (8)

I can't stop watching this video... it's mesmerizing.

Did the stub axle break in two? In other words, is the castle nut still threaded onto a piece of the end of the axle, rattling around on the outboard side of the hub?

Or did the nut come off, thus permitting the axle to pull out of the hub?

aidandj

iTrader: (5)

It almost looks like it stripped the hub

curly

iTrader: (25)

That or it broke the threads off the end. Either way the wheel bearing is toast. Hub might be fine, but I also don't think there's enough room for it to come fully out if it's just the threads. Might of stripped just half the splines after the threads broke. That's my bet!

patsmx5

iTrader: (16)

Yes, that's what happened. When I pulled the wheel, the stub axle piece still had the nut on it, and was poking out about 1.5". It knocked the center cap off when it failed, lost that at the track. :(

The inboard cv closest to the diff slung the metal band off, and had grease leaking out of the boot a lot. I don't know if there is damage to the inboard cv.

The outboard cv looks fine. No leaks, no obvious damage.

The stub axle part that goes into the hub had a bad day.

Excuse my ignorance, but Curly mentioned the wheel bearing is done. Why so? That sucks if I gotta replace that too...

Also I grabbed a stock 99 axle, and the outer cv is completely different dimensions. MSM being bigger. So no-go on patching this axle with the old regular axle.