Almost anyone who has rallied a mk2 VW has found themselves short a wheel at one point or another. I know it’s happened to me three times, twice to Fiorelli, and who can forget the infamous Prescott 2010 where Van Brocklin didn’t let the lack of a rear wheel stop him from a class win on a 20 mile stage…

The rear stub axles shared by mk1, mk2, and 4-lug mk3 VW’s are prone to two different types of failures. The first type is an overload failure caused by hitting something. In my experience it doesn’t have to be anything too solid - just going sideways into a berm can make your stub axle bend like this (classic plastic deformation caused by overload):



When that happens, the bearings fail and eventually the wheel falls off after you drive some distance down the road thinking you got away with it…

The second and more worrisome type of failure is caused by fatigue. You can generally avoid bending the stub axle by keeping it on the road, but unfortunately that’s no guarantee the wheel will stay attached to the car. Here’s a stub axle from my car that failed without me hitting anything:



You can see the fracture is perpendicular to the surface at the root of where the material necks down for the outer bearing. There’s no deformation at all that you would expect to see in an overload failure. Examination of the fracture shows beach marks consistent with fatigue. This Febi stub axle had about five rallies on it before it failed.

Here’s a second example from Fiorelli’s car at Mendocino 2013 next to mine. They both show the same fatigue failure mode.



It’s a also a Febi, but with only two rallies on it before it failed, causing this damage to Eddie’s VW:



Having established that these failures are not flukes, there is a need for a solution. There’s a wealth of information in this thread: http://www.rallyanarchy.com/phorum/read.php?5,77312,page=1 especially the post by danster that points out the VW Polo has a larger thickness stub axle that will bolt directly to the mk2 rear beam.

The Polo stub axle is much thicker than the mk2 stub axle (28mm vs. 17mm for the mk2 at its thinnest section where it bends), and also has the advantage of using a nice big sealed bearing. The design is actually quite similar to the mk4 5-lug stub axles. The bad news is these cars were never sold in the U.S., but the good news is parts are available in Europe or Mexico. Not all Polos or Ibizas had disc brakes so beware. The drum brake parts will not work (unless you retain drum brakes).

Here's a list of part numbers you need for the conversion (Note, there are typos in the various threads on this topic out on the internet):

1 - right stub axle 6n0501118
1 - left stub axle 6n0501117
2 - hubs with nut and cap 6x0598477
2 - brake discs 6n0615601a
4 - stub axle to brake carrier bolts n90740301

You can reuse the following mk2 parts:

Brake Calipers
Brake Pads
Brake Caliper Carriers
Brake dust shields
Stub Axle to Rear Beam Bolts

You can't reuse the stub axle to brake caliper carrier bolts because the mk2 bolts will be too short. The Polo stub axles are thicker in this location. I bought a box of M10 x 1.25 x 30mm bolts from McMaster-Carr instead of buying the VW ones.

I found a dealer in Mexico City willing to sell me everything new from VW and ship it to the U.S. It would have cost me over $1,500. Instead I purchased a complete used rear end off of eBay.co.uk. It cost me 100GBP + an extra 100GBP in shipping. Total was about $325. This got me the stub axles and hubs. They were a lot rustier than the parts you get from junkyards in SoCal, but after a couple of hours with an angle grinder and a wire wheel they cleaned up fine.







I then purchased new brake discs, stub axle nuts (N90654501) and dust caps (1J0501249C) from the VW dealer in Mexico. This cost me $250 shipped to the US. So the complete cost for everything was under $600. I bet it could be done for cheaper if you can find the right vendors. However, I think it's totally worth it at that price for the peace of mind that your wheel will not fall off...

Oh, you also need the little screw that holds the brake disc to the hub. It's the same as the one used in the front discs in the Corrado, so I had a couple extra laying around anyway. I also installed studs, but obviously that's optional.







I finished Prescott this weekend with all four wheels attached to the car. Success!

Sourcing parts from across borders can be hit or miss. What happens when you break a stub axle or have a hub failure? Are the Polo stubs the same diameter as the mk4 VW? I read somewhere that they weren't, but then again.... this is the internet.
Or you use these. $150ish for the set, and made by yours truly. They use all parts that can be sourced new from any autoparts store, in any country. Or your favorite rally parts depot.


Edited to not sound like a crass jerk.



Edited 1 time(s). Last edit at 10/08/2013 11:58PM by Robert Culbertson.

From the other thread:

Quote
danster
My dog needed out for a piss so just picked up a front VW 256mm vented disc from the shed.
It fits perfectly on the rear Polo hub, it centres correctly, it's 4 x 100, even the little brake disc retaining screw is in the right place.

And this also means the front 239mm vented or solid disc will fit.

Erik, if you've got your car up in the air can you check to see if the front discs available here will work? That could save some buckskies.

---

Self-righteous douche canoe

Quote
hoche
From the other thread:

Quote
danster
My dog needed out for a piss so just picked up a front VW 256mm vented disc from the shed.
It fits perfectly on the rear Polo hub, it centres correctly, it's 4 x 100, even the little brake disc retaining screw is in the right place.

And this also means the front 239mm vented or solid disc will fit.

Erik, if you've got your car up in the air can you check to see if the front discs available here will work? That could save some buckskies.

I'll try to check. I run Corrado front brakes but I think I may have some standard front discs up in the attic somewhere. I'm sure the disc will slide on, the tricky part will be if the carrier fits.

Quote
Robert Culbertson
Sourcing parts from across borders can be hit or miss. What happens when you break a stub axle or have a hub failure? Are the Polo stubs the same diameter as the mk4 VW? I read somewhere that they weren't, but then again.... this is the internet.
Or you use these. $150ish for the set, and made by yours truly. They use all parts that can be sourced new from any autoparts store, in any country. Or your favorite rally parts depot.


Edited to not sound like a crass jerk.

It's true spares are not readily available. But everything is OEM and bolts on. I doubt I'll break these stub axles with anywhere near the frequency of the mk2 stub axles.

The Polo axles are 28mm. I believe the mk4 axles are 30mm.

I considered your adaptor plate, but it doesn't solve the 5 lug problem.

Quote
Erik Christiansen

Quote
Robert Culbertson
Sourcing parts from across borders can be hit or miss. What happens when you break a stub axle or have a hub failure? Are the Polo stubs the same diameter as the mk4 VW? I read somewhere that they weren't, but then again.... this is the internet.
Or you use these. $150ish for the set, and made by yours truly. They use all parts that can be sourced new from any autoparts store, in any country. Or your favorite rally parts depot.


Edited to not sound like a crass jerk.

It's true spares are not readily available. But everything is OEM and bolts on. I doubt I'll break these stub axles with anywhere near the frequency of the mk2 stub axles.

The Polo axles are 28mm. I believe the mk4 axles are 30mm.

I considered your adaptor plate, but it doesn't solve the 5 lug problem.

We solved that a long time ago. Called drilling. I drilled out a MkIV front hub for Tom Buress cause it splined onto some bigger CV or something--(I just machine what I's told but the holes in the hub are minor problems..)

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

why not just convert to five lug ?

---

I would rather drive a slow car fast as a fast car slow!
first rule of cars: get what makes you happy, your the one paying for it!

Quote
tdrrally
why not just convert to five lug ?

Because most guys have PILES of 4 lug wheels.

Drilling 3 holes (one is already in the right place) is easier than spending hundreds and hundreds of dollars.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

I think both approaches are valid. One has an appeal for guys who like bolt-on stuff and are willing to pay a smidge more for it. The other has an appeal for those who're looking for a cheap-but-requires-some-work solution.

Frankly, I hate working on frickin' cars, so a simple bolt-on solution has appeal, especially if it's only a few hundred bucks

More options is better, eh?

---

Self-righteous douche canoe

i think in terms of how many 5 on 100mm wheels are out there in the salvage yard for 10-30 dollars each
steel to alloys

i do see the point if you have a few sets of rally wheels (sparco etc.)

---

I would rather drive a slow car fast as a fast car slow!
first rule of cars: get what makes you happy, your the one paying for it!

Quote
tdrrally
i think in terms of how many 5 on 100mm wheels are out there in the salvage yard for 10-30 dollars each
steel to alloys

i do see the point if you have a few sets of rally wheels (sparco etc.)

I know there's lotsa 5 on 100 but the VW wheels aren't bad. and that's "pretty good" if they're not bad... A lotta wheels are wrong offset---the later fad was to go deeper like ET49-50---and a lot of questionable strength.
VW wheels may bent but I don't recall seeing any break, like chunk off hunks---and I have seen that on too many Japonaise wheels.

Even if they were OK, finding what you want and paying several hundred more--and then mounts and dismounts adds up where drilling and pressing in some good studs is a one time deal--3 holes.

(I'm saddled with one car, the Saab with 4 on 4.5" and needs skinny the other cars I have are all 4 on 4.25"----grrrrrrrrrrrrrrr....pain in the drain cause I'd love to use snows on everything...be nice if I could use one set on the Xratty OR the Saab)

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

my mush tang has the 4 on 4.25 issue
up side is its cheap and easy to change to a 5 on 4.5
then i can sell the 16x7 wheels with 4 on 4.25

the pony wheel would look good on an xratty

---

I would rather drive a slow car fast as a fast car slow!
first rule of cars: get what makes you happy, your the one paying for it!

Quote
hoche
I think both approaches are valid. One has an appeal for guys who like bolt-on stuff and are willing to pay a smidge more for it. The other has an appeal for those who're looking for a cheap-but-requires-some-work solution.

Frankly, I hate working on frickin' cars, so a simple bolt-on solution has appeal, especially if it's only a few hundred bucks

More options is better, eh?

Yeah, that's the point. If you want to drill and tap the mk4 hubs (and brake rotors) go ahead. I'm just passing on what I learned, and this solution works for me. I found it very simple and ordering everything international was not a problem at all once I figured out what I needed.

I would go 5x100 if I was starting from scratch. But my car came with 12 compomotives a when I bought it, so I'd like to stay with 4x100.

Oh, and I still bring the old style stub axles to rallies as spares.

-Erik

Some might suggest the extra weight of the fifth lug combined with the extra time dealing with the extra lug nut in service or roadside changes is a detriment as well. (As I understand it, Prodrive went to a 4 lug system on the WRC Impreza for those reasons)

---

First Rally: 2001
Driver (7), Co-Driver (44)
Drivers (16)
Clerk (10), Official (7), Volunteer (4)
Cars Built (1), Engines Built (0) Cages Built (0)
Last Updated, January 4, 2015

Quote
john vanlandingham
Blame is for idiots. losers.

That ^ made me chuckle, thanks.

Erik, the adapters I make use a mk4 hub that had a few hole drilled in it. That takes a bit of time, but nothing too complex. For rotors, I have a few options. Currently I'm using a early mk2 solid front rotor on the rear. It's a 4-bolt and super easy to find. You do have to grind the caliper and carrier to fit (just once) over the slightly wider rotor. I have been looking at using a MR2 rear rotor, as they are the correct width and 4X100.

I am working on the machining right now of the 5X100 kit. Uses all mk4 stuff, just bolted onto the mk2/3 beam.

I do like how the Polo stuff doesn't widen the rear track. My adapters are 0.9in thick, so your track widens about 2in in the rear.