Outer Limits 4x4 Board

A few weeks ago I had the pleasure of breaking an axle in a D2. Looking at the pic of where my axle broke it was on the axle side of the flange which is at the wheel hub end. The axle did have a twist down at the splines at the diff end, but surprisingly ended up failing at a central location. Surprisingly the splines at the hub end were perfect especially considering it was preloaded with the nut on the end, and that was the case on the other axle also, and I'm not quite sure why this is the case as both axles at the diff ends were twisted. Anyhow, looking at the design if the axle did fail at the ends of the wheel hub splines, will this cause the hub flange (5) to dislocate from the hub bearing (3) and the wheel to come loose presumably held on by the brake disc rotor or at worst fall off? Any comments on the materials, failure, design, mechanics or whatever would be welcome in trying to understand it properly.

Hmm, seems to be the case that if the axle does fail between the end nut and the flange the hub flange does come loose from the hub bearing assembly

Tyre size, engine, and circumstances when it broke, please?

I'd like to understand the strength limits for the P38, which has a similar design.

Are you getting the Maxi-Drive rears for your DII, or do you replace with stock?

wilsby wrote:Tyre size, engine, and circumstances when it broke, please?

Simon was on his 33 MT/R`s that day, he`s got the Td5 engine.

This is the boom point
http://craig.4wdpics.com/lyle/DSC00117.html

Gonzo wrote:

wilsby wrote:Tyre size, engine, and circumstances when it broke, please?

Simon was on his 33 MT/R`s that day, he`s got the Td5 engine.

This is the boom point
http://craig.4wdpics.com/lyle/DSC00117.html

Thank's, my P38 is on 32"s, and it seems it was a good decision to order MDE axles.

Is the Disco locked in the rear, and auto or manual? I have opted for TrueTrac's front and rear, and hope that will help keep the halfshafts healthy.

Its an auto with open diffs at the time (now twin locked)

Simon reckons he did the actual damage a few weeks earlier when he was running his 34 inch simex`s, and it just happened to snap when this mild load was placed on it.

Jeeze, i sound like Slunnies bloody personal assistant !

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hehehe - just noticed that my avatar is the hill when it went boom

Wilsby, there are some more pics of the broken axles and diff at:
http://www.4wdlinks.com.au/gallery/album148

The axles break and the diff planetary gears are also pretty marginal in them. I'm pretty sure we have the same axle sets anyway. There are people using the TT's and lockers with factory axle half shafts though I tend to think unless they go pretty easy that something is going to break in them. The TT's and maxi axles should be a really good combo.

I've got lockers and Maxi drive rear axles in it now. Unfortunately they are still developing the front axles/CV setup at the moment, so hopefully it will still be strong when these come on line.

I think the damage was mainly done when I got some air on a diagonal rock step about 3/4 of the way up a hill and landed it full stick in low range. The rotoflex in the tailshaft failed at that point, so I'm assuming it twisted the axles also.

Judging by the relatively clean break it looks like it may have been caused by a stress raiser due to poor machining practice. the axle looks poorly made and finished and would not have much torsional flexibility.

Slunnie wrote:I've got lockers and Maxi drive rear axles in it now. Unfortunately they are still developing the front axles/CV setup at the moment, so hopefully it will still be strong when these come on line.

I think the damage was mainly done when I got some air on a diagonal rock step about 3/4 of the way up a hill and landed it full stick in low range. The rotoflex in the tailshaft failed at that point, so I'm assuming it twisted the axles also.

Yep, the P38 front has the same weaknesses as ABS-age Defender fronts, and I would assume DII fronts. The axle diameter is smaller at the CV end.

Btw, DII and P38 rear halfshafts are similar, but not identical. P38's are approx 10 mm longer, have a machined surface for an oil seal just inside the flange, and the flange has a larger diameter to fit the ABS ring. Strengthwise I'd assume there is no difference.

daddylonglegs wrote:Judging by the relatively clean break it looks like it may have been caused by a stress raiser due to poor machining practice. the axle looks poorly made and finished and would not have much torsional flexibility.

I have to admit the axle surface did surprise me by the almost cast finish in the non-machined areas, and the bottom pic is a great example of this.


Wilsby, you Maxi'd the rear, but what did you end up doing with the front end in terms of the inners and CV's?

I got a wrong shipment, so the Maxi's are actually not in the rear yet, but it will happen within weeks.

I'm leaving the front with stock CV's and halfshafts at the moment. I talked to Mal about 6 mo ago, and he said he could probably do something for the front, but I'll wait for some more development there. The theory/hope is that the stock front will hold up on 265/75-16 BFG M/T's and a limited slip diff.

I will keep the P38 mild for a while. It's currently the family favourite and my tow truck. But I have been taking some measurements for a possible 4W steer Volvo portal conversion...