The broken aftermarket CV-axle issue

[Ed Lijewski]

Dean isn't on FB MCA so he doesn't recognize the name tagging format in that screenshot. Leo now owns the car he just removed that halfshaft from. Leo bought the XR from VWDamien, the guy Noah referred to. VWDamien wasn't much of a wrench but did ask a lot of questions to his credit. He posted a photo of a bad halfshaft asking how/why it broke. I replied, and Noah did as well. My response was we don't know why they break that way and to just get another unit, install it, and move on. Apparently he didn't want to spend more $ on it and reinstalled the broken one (hard to believe it could be driven). My guess is he installed a new unit on that side but then in beating on the car driving it the other side failed after Leo bought it from Damien.

YMMV

[brokencase]

Uh...Houston...We have a problem.

Time to revive this thread.

I was a little delayed getting the Scorpio inspected this year. My brother passed away this year and my father has had some problems. I have been into and out of so many hospitals and doctor's offices this year, it has been unbelievable.

Anyhow, The Scorpio passed PA inspection yesterday with flying colors and my mechanic gave a "thumbs up" on my DIY stainless exhaust system.

So, today it was nice out so I thought I would take her out to the post office. On the way back I was at a stop light pulling away (with modest torque)
and suddenly BOOM! At first I thought it was the transmission. But then I heard the "clunk clunk" at the rear and it soon became clear what had happened.

I was fortunate, I was able to coast off the main road and into my neighborhood. I parked her by the curb, put a note in the window and walked home.

My brother and I just finished dragging her home with a tow strap behind my truck. It's in the garage and at this point I don't know which axle failed.

Ed, since I am now in the bed with you on this - is there any recourse with RockAuto on these cheapo axles?

Pretty pissed.

[my8950]

Ed, since I am now in the bed with you on this - is there any recourse with RockAuto on these cheapo axles?

My guess is no, Ed would certainly not leave us hanging with any info on this, especially if he was able to get a credit on the hokey parts he received.

[brokencase]

OK, Riddle me this Batman...

I wish to avoid Cardone and Trakmotive brand axles. As I recall Ed seemed to indicate both of these have failed.

If I look at RockAuto and at the Cardone 667018 they state that the left Scorpio axle crosses with 66-79 VW Transporter (manual Trans) and it has a compressed overall length of 18.75"

So if I go to look at the Transporter under Rockauto they list the APWI axle that fits the same application as the Transporter, and it has the same compressed overall length of 18.75". However if you click on the the APWI part number (VW8061) it states that it only fits the Transporter.

To add to the entertainment, the recommended left axle for the Scorpio from Trakmotive has a compressed overall length of 18.9" and this also crosses to the Transporter

Does anyone know the true compressed overall axle lengths on the original Scorpio axles? Are they really the same for XR4ti?

My fear is that somebody in the past thought they were the same as Xr4ti when they are not... and this has led to a confusion.
Just like the steering racks are the same except for the tie rod end lengths.

[brokencase]

I thought I would take a look at the CV axles available from Europe and see if they had some published lengths.

https://www.onlinecarparts.co.uk/ Lists the following lengths for Scorpio
left axle 478mm 18.81" or 480mm 18.89"
right axle 520mm 20.47"

Similar results for the XR4 Sierra. So it looks like XR4ti and Scorpio do indeed share the same axle lengths.

Interestingly these axles are all "out of stock" at that website.

So the "Trakmotive" brand lengths at RockAuto appear to be reasonable.

The 18.75" option offered by Rockauto CardOne is a little short but I'm not convinced that the .05" is a problem. The CV's do afford some lateral play.

[my8950]

Similar results for the XR4 Sierra. So it looks like XR4ti and Scorpio do indeed share the same axle lengths.

I can confirm that Scorpio and XR axles are the same as with the ones I rebuild, have been installed on opposite vehicles.
Example is Ed's Scorpio, the axles I did for him came from an XR.

I do not have any information on measurements collapsed & all that.

[Ed Lijewski]

No response from Pat Goss to whom I addressed my message on this matter (scroll above). I'll now send a message to Tom Taylor of Rock Auto (if I can find an address for him) as RA has a more direct interest in it selling reliable products.

I still suspect: possible factory misassembly of bearing cages (upside down), wrong axle assembled (slightly shorter than Merkur OEM), incorrect aligning of ball bearings with bearing race.

As the CV units are designed to allow lateral movement with only the boots restricting recommend buying a GKN CV joint and using the same axle from your broken unit.

It seems that XR owners with huge power setups or who race those cars install GKN CV joints on XR axles, and never have problems with their CV axles.

Ckiff Walton says there are several GKN part numbers identified that will work (MS3K020, MS3K023, and MS3K038) but availability seems limited.

Get the GKNs from Tim Bevan (Autohaus, IIRC).

Screenshot_20211104-140259_Lite.jpg (410.6 KiB) Viewed 4044 times

Screenshot_20211104-140322_Lite.jpg (376.71 KiB) Viewed 4044 times

[I made a heroic effort to stifle the urge to third degree interrogate you up and down, inside and out, about whether you mis-installed that CV joint, if your shocks or stabilizer are worn/misaligned, if your driving style sucks... It was difficult. ]

YMMV

[my8950]

Guys, I have been thinking this for a while, but seeing more here actually made me get up and go check.
When I got your failed axles Ed, I did notice this but wasn't sure how much different they really are.
Attached are some photos that will clarify. The axles which you sent me have a different pitch on the spline, so I can't say that getting some GKN or other ends will work. These axles seem to be their own entity, parts won't interchange, at least this part since you can't put a stock axle in the Chicom splined section.
On the left is the Ford part that comes on our stock axles, on the right is the part from Ed's failed axle.

[Ed Lijewski]

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From Jeff's road trip parts photos:

Screenshot_20211104-192638_Lite.jpg (816.16 KiB) Viewed 4039 times

YMMV

[brokencase]

I'm going one more time with aftermarket axles. I'll keep a spare CV joint left over from the bad axle in the back of the car along with the tools to change on the road.

I just don't like the idea of driving a significant distance not knowing if a CV is going to blow at any moment.

Maybe the best solution is to call EMPI and tell them I want a Transporter and Vanagon axles (those that are the proper lengths for the Scorpio)
and have them install their heavy duty CV joints on them.

FWIW, it was my passenger side outer CV that blew.

[brokencase]

Here are what I believe are the EMPI equivalent axles for Scorpio.
These are EMPI's standard axles.

My assumption is based on cross referencing the part numbers from RockAuto..
Which is...
Left Transporter manual trans 66-79 18.75" OAL
Right VANAGON 1983-1991 20.5" OAL

https://empius.com/products/vanagon-a-t ... 1-203a-10/

https://empius.com/products/vanagon-a-t ... 01-203a-5/

$162 + $123 = about $285 plus shipping.

[Ed Lijewski]

My sense is that the failures are likely caused by axles marginally too long. My failures each resulted in the bearing races pushed out of the cages.

20210607_105438_copy_756x756.jpg (140.02 KiB) Viewed 4003 times

To add to the entertainment, the recommended left axle for the Scorpio from Trakmotive has a compressed overall length of 18.9" and this also crosses to the Transporter

My last axle failure-the one at Carlisle-was a new Trakmotive unit. About 10 days before that I experienced an axle failure (in the same car, also a Rock Auto bought unit) midday on a Friday and hoping to still make Carlisle the next week, and not knowing for certain which side CV axle failed as I was on the roadside I ordered from RA Trakmotive CV axles for both right and left sides hoping they would arrive by mid-week next, in time to install the new axle and test drive a few miles before Carlisle departure day. So I still have the unopened Other side Trakmotive unit.

If I were to order axles from EMPI I'd order a shorter OAL than 18.9". The failures as in my photo above clearly point to excessive outward pressure on the moveable parts. When the CV axle either droops or rises (rebound effect) the unit length extends. When the CV axle is horizontal or nearly so as in most driving an axle marginally too long exerts pressure on the moveable parts. How long before failure occurs can't be determined precisely but seems certain to occur. Three of my failures (I can't recall the earlier ones' circumstances) occurred shortly after accelerating lightly, two VERY lightly) from a dead stop, just as Dean's, with no forewarning by sounds or vibrations from the drivetrain.

But I wouldn't fugg around with EMPI or other axles, even slightly shorter ones, when it's still possible to get rebuilt Merkur XR/Scorpio units, or possibly even still installed units from a parts car for rebuilding.

YMMV

[brokencase]

Took the axle out and examined. Quite a surprise.

BTW this axle brand is APWI

There is nothing metallurgically broken with the parts of the failed CV joint. Nothing wrong with the circlips or the weird inner clip.

What has happened is the cage and balls "came off the track" of the races and hopped into the boot.
Sort of like a dislocated shoulder. So the cage and all the balls were in the boot.

I thought for sure I would be looking at broken parts given the BOOM! of the failure and the subsequent noise the CV made as I tow strapped it back home.

I thought the cage would be in pieces, but it looks fine.

Furthermore, the boot is intact. It was all twisted up when it was in the car, but once I got it out it sprung back to shape.

The way I see things is that the sheet metal flange that holds the boot onto the outer race also has the duty of keeping the balls from getting into the boot. But it does not do a good job doing this.

I was thinking I could machine on the lathe a large "washer like" disk out of steel that would bolt between the stamped flange and the outer race that would form a ledge that would prevent the balls from hopping into the boot. Still contemplating this... Alternatively, it may be possible to peen the flange at the six points where the ball races meet the flange in order to make it harder for the balls to come into the boot.

Ed, btw...the Europeans don't call it "Compressed overall length". The length they refer to is the length of the inner axle, nothing more.

This axle is 20.5" long.

Is it possible we are looking at perished rubber elsewhere in the swing axles that is allowing the hubs to take an excursion outward and this is what is causing the failures? I could imagine outward movement leading to the balls and races dislocating as I have observed here.

Also - There is no inward/outward orientation with regard to Merkur axles - correct? It is the same CV on both sides - Right?
The reason I ask is this particular axle has a machined notch on the axle near one of the boots. Just wondering if this was to be orientated towards the inside or outside of the vehicle. I didn't see anything regarding this in the instructions.

[Ed Lijewski]

Is it possible we are looking at perished rubber elsewhere in the swing axles that is allowing the hubs to take an excursion outward and this is what is causing the failures? I could imagine outward movement leading to the balls and races dislocating as I have observed here.

Also - There is no inward/outward orientation with regard to Merkur axles - correct? It is the same CV on both sides - Right?
The reason I ask is this particular axle has a machined notch on the axle near one of the boots. Just wondering if this was to be orientated towards the inside or outside of the vehicle. I didn't see anything regarding this in the instructions.

From my reading anything/everything about Merkurs over ~20+ years, Scorpios in this context, I don't believe anyone has reported the type of failures documented here as a reason for installing new CV axles; rather that was done to resolve broken CV boot issues. John Brennan, whose axle failures I cited above, has had an XR in his family since 1988 and was active on Merkur listserves and internet fora , and when he installed two new CV axles for cracked boots on the original units and each new aftermarket unit failed almost immediately he knew of no other similar failure and was mystified why the failures occurred.

It seems every non-race car driving
owner who kept OEM axles installed didn't experience these failures.

Re orientation of the units, none of the instructions that came with the various manufacturer's units I installed, nor the Scorpio and XR Service Manuals, say the units have specific inward or outward orientations.

Anyway, I just went through my rockauto orders and I have TRAKMOTIVE VW8063 (right) and TRAKMOTIVE VW8045 (left)
That was in early 2018.

Above you note the failure you disassembled is an APWI unit (?).

YMMV

[brokencase]

Put my new axle in. But before I did that I measured diff flange to hub flange on the car. It is 20 inches.
This is with the jack lifting under the swing arm so the suspension is slightly compressed.

We are talking about the passenger side here and the CV axle is 20.5"

So this means the CVs crowd inwards about .25" on each side when the axle is installed.
I set the new axle on the ground and moved the outer races to that position and it did not seem unreasonable to me.

Note also that this means the balls/races move away from the boots. So.. how my other axle failed with the balls/cage ending up in the boot is a mystery to me and I cannot attribute "wrong axle length" as the culprit here.

The only thing is what I mentioned about the flange previously. That it allowed the extra lateral movement for the balls/cage to go into the boot.

Agreed on the swing axle bushings. I looked at them when I installed the new axle and they appear to look OK.