Step 6: Axles
Well, I picked up my axles today. $400 later....don't tell the wife, hide the receipt . I once read on the Vortex that when you start hiding the parts reciepts you know you have a VW problem.
- Purchased two 1992/1993 Eurovan (T4) front axles without ABS. Pulled CV joints off these and the two Mk1 axles and cleaned up the axles.
- Took all the axles to axle guy and he cut them up and welded them back together at the appropriate length, such that the inner end/spline was T4 and the outer end/spline was Mk1. See below for use of only Mk1 axles in this process.
Note to file: I had two driver's axles and two passenger axles that were slightly different lengths than the other. And there are solid Mk1 passenger side axles and tube passenger side axles (see photos near bottom of this post). I am not sure if I had Mk1 vs. Mk2 axles, or what, but I had two different lengths and two different styles that seemed to fit my Mk1 rabbit. I just used my original axles for this projects to be sure I was keeping apples with apples. But, to shorten the passenger side axles like I do below, you will need a solid passenger side axle!!!
The Long Story:
On the 020 transmission, the distance between the axle flange seats is 9 3/16". On the 02M transmission, the same distance is 11 3/4". Therefore, the total length of both axles (COMBINED) needs to be 2 9/16" shorter on the 02M than it was on the 020.
I measured this flange to flange distance on each tranny, and also the "axle length" distance between each flange and its corresponding wheel bearing axle seat (driver's side and pasenger side). With vehicle resting on the ground (weight on tires), my original 020 driver's side flange to bearing measurement was 17 3/4" and the passenger side was 26 1/8". (This distance will vary a bit car to car depending on ride height, spring type, strut insert stiffness, etc.) With the 02M mounted, these same distances were 16" and 25 3/8". Subtracting the 02M lengths from the 020 lengths gives a 1 3/4" difference on the driver's (short) side and a 3/4" difference on the passenger (long) side, with a total measured difference of 2 8/16"....which miracuously was only 1/16" off from my measured flange to flange difference above. So, I feel pretty good about the amount of axle shortening that was needed...specifically, 1 3/4" off the driver's side and 3/4" off the passenger side axles. This should be consistent for all Mk1s, but make your own measurements.
The 020 inner CV joint is 100 mm diameter but the 02M flange is for 108 mm CV joints. In addition, the spline on the 020 axles is smaller and has more splines than the original 02M axles, AND the 02M axles are a bigger diameter tube, possibly leading to axle to frame clearance issues on the longer passenger side of the vehicles.
Solutions 2: Change inner axle spline and inner CV joint to 108mm or make adapters that fit between the 100 mm CV and the 02M Flange. Since you need to shorten axles, it did not really make sense to me to create an adapter like this:
Because this adapter shortens the cv to cv distance even more (increasing angle) and you have to make short axles AND the adapters. Double effort.
So, I did some research on Vortex, wrote a few PMs and emails, and found that the 1991-1993 Eurovan (T4) had 108 mm inner CV joints that fit the 02M flanges perfectly (The T4 inner CVs look identical to the 02M inner CVs). AND, the T4 108 mm CV axle spline is the same diameter and spline count as the Mk1 rabbit axles. HOWEVER, the spline shape is slightly different between the Mk1 and T4. BUT, Even with this slight spline shape difference I found that you could pretty readily press the T4 axles onto and off the Mk1 axles without doing significant damage to the splines. In fact, I could not see any damage to either the axle or CV spline after removal. What I FORGOT to check is whether you can put the locking Circlip on the Mk1 axle when the T4 CV is pressed onto it. I think it will fit if you DO NOT put the backing washer onto the Mk1 axle first...just let the T4 CV bump up against the angle at the end of the splines. Without the washer, I think there is enough space to get a circlip into its groove, but CHECK THIS BEFORE you make your shortened axles with Mk1 inner splines.
Regardless of the "rough fit" of the T4 inner CVs on the Mk1 Axles, since I had to cut and shorten the axles, I chose to purchase T4 axles and use a section of the inner T4 axles & splines as the inner portion of my newly shortened Mk1/02M axles. Thus, assuring a true inner and outer CV fit.
There are some other potential options out there that i discussed a bit here: http://forums.vwvortex.com/zerothread?id=3741455
Once I knew how I was going to go about the axle change, and had the measurments, I tried to cut the axles myself with a horizontal metal band saw. What to my dismay did I find, but that the axles are hardened and the saw wouldn't cut...to be expected I suppose, but I didn't really think about it until this point.
Since I didn't know how deep the hardening went, and I didn't have the tools to work with hardened steel, and didn't want to buy them, I found a local guy who does contract work for a local ring and pinion shop, and had him shorten, weld, and straighten my axles for me.
Here's the process he used:
1. Cut the axles...cutting the slightly larger T4 axles an inch longer than needed.
2. Lathed the cut end of the T4 axle so it had a 1/2 inch diameter by 1" long stem (male end).
3. Lathed a 1/2 inch diameter hole in the cut end of the Mk1 axles.
4. Beveled T4 AND Mk1 cut ends at a 45 degree angle down to the base of the 1/2" stem and down to the end of the Mk1 axle where the lathed hole started. The bevels was cut so that when the axles were mated together, the two 45 degree angles met at the bottom/middle, but instead of a "V" shape at the bottom of the bevel, he made it a "U" shape, which evidently allows for a stronger first weld (sharp weld angles are weaker than rounded weld angles).
5. Threaded the stem and tapped the hole in each set of axles, then screwed the 1" long stem into the tapped hole such that the "U"-shaped bevel met cleanly in the middle.
6. Heated the axles a bit (I guess about 600 degrees is optimal??? and heat on the entire axle just before welding helps keeps the carbon from sucking out of the hardened steel and into the hotter weld) and stick welded the first weld layer around the bottom of the bevel using a high penetration welding rod. Evidently, the stick welder penetrates better than a wire-feed, although I have been told that using flux-core wire AND shielding gas on a mig wire feed welder also penetrates very well. After a round or two around the axle splice with the stick welder, he then continued to fill the bevel with a mig welder, turning the axle so that the weld heat was applied radially around the axle, not all in one spot at one time. This helps reduce warpage.
7. Following welding, he cleaned up the weld area on the lathe and measured for straightness. The long passenger axle warped about 0.100 inches out of true, so I think he lathed off a bit on the "high" side to bring it within 0.010 of straight. then measured wobble at the ends and found them to be off only by about 0.002 inches, which should be plenty good. The shorter driver's side axle was 0.040 inches out of true in the middle near the weld, but since the ends of this axle were also within 0.002 inches and he did not get "wobble" at 600 rpm on his lathe, he just left this short axle without "truing it up".
In this process, I found that the axles are only hardened about 1/8" of an inch or so into the shaft. So, if you are doing this, it is quite possible, using a cut-off wheel, to first grind into the axle through the hardened part, then cut the rest of the way with a good steel band saw. Once inside the axle metal is relatively soft and easy to work on. Now I know I can play with these on my own if I want to in the future.
- So, I brought the axles home and this is what they looked like:
you can see the long axle was turned most of its length to get rid of the warpage and make it the same diameter its full length. The T4 axles are slightly larger diameter than the Mk1 axles...and you can see the slight change on the shorter axle in the above picture.
I then painted the axles and put on new Mk1 larger diameter (Scirocco; 90 mm) outer CV joints and new T4 inner CV joints and the axles looked like this:
Note, the end cap like this:
was taken off of the 02M CV. It is a great addition to stop CV grease from flinging all over the engine bay, and makes the fit onto the 02M flanges just perfect
The new CV joints all came with new CV-to-flange bolts, which I used to attach the inner CVs to the 02M flanges.
When I first tried to put my axles in, with the tires hanging, I found that I could not fit the 108 mm inner CVs up into the engine compartment far enough to allow the outer CV splines into the hubs. the bigger Tranny and bigger CVs just don't squeeze up far enough to allow outer CV to clear the wheels. So, I undid my ball joint, pulled the hub out a bit, put the outer CV into the hub, then pushed the hub and axle assembly onto the inner 02M axle flange, and put the ball joint stud back into the hub/spindle. Kind of a pain, but only one ball joint bolt...so not too bad.
The fit seemed very good, such that when the outer CV was locked into its running position, and weight off the wheels, the lowest edge of the inner CV rested in position on the inner flange. Because of the unweighted angle of the axles, to insert and tighten the inner CV mount bolts, I had to pull and angle the inner CV a bit. I think this is a fine fit. Will report again later on fit once I get weight on the wheels and drive a bit. Here are some picks of axle fit:
And here is a comparison of my shortened axles, Stock Mk1 axles, and the stock 02M axles:
I think the stock 02M driver's side axles may be an appropriate length to be used in this swap, if you wanted to have the outer axle spline ground to fit an 020 outer CV.
A bit more information to come!!
Modified by CrewCabCaddy at 12:09 PM 6-4-2009