I THOUGHT I BROKE A MARKS PORTAL HUB

ByUnsealed 4X4April 1, 2019
3 MINUTE READ
I THOUGHT I BROKE A MARKS PORTAL HUB
SH#T. Steve’s first thought when his right boot landed him in some High Country strife…
Words and Images by Harry Temple

I had just said goodbye to Steve and his portal-axle 79 Series ‘Cruiser and begun winding my way back out to Mansfield. Had I waited another 10 minutes, I would’ve heard his call over the UHF. Steve had his eyes on a north to south solo ascent of Nobs Track, but things didn’t go as planned. Before we dive into what happened, it’s important to remember it really wasn’t too long ago that portals were nearly unheard of in a daily driven 4WD. Steve had over 90,000 trouble-free kays on his portals and they are still by far his favourite modification. Now that more sets are popping up on rigs across the country, people like him are beginning to test them out … and find the limits of the older, first-generation gear.

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WHAT HAPPENED?
Intending to camp up on the top of Nobs Track to film some content, Steve wanted to reach camp before dark, so he was pushing the 79 Series up the first real steep section when he popped the driver’s front up in the air. What the footage below doesn’t show, is how the vehicle shifted and unloaded the remaining wheels, all except for the left-hand rear. In an effort to keep moving and not lose any more momentum through the weight shift, he sent all 748Nm through that one wheel and coaxed out that all-too-familiar crunch that us 4WDers collectively dread. Had I still been with him for this particular section, I probably would’ve been out running the winch line to avoid the situation altogether, but as he was one-out on some pretty hairy terrain, getting out of his vehicle wasn’t really an option.

COULD YOU GET HOME?
Yes. Luckily, the breakage occurred near a hairpin corner, so there was space to turn around, even if it meant admitting defeat. Given that he couldn’t hear any grinding or metallic sounds from the differential, the decision was made to try and get as far towards home as possible to properly diagnose the breakage. He made the 100km journey back home without incident after locking the hubs and driving home in front-wheel drive.

WEAKEST LINK
Steve’s background in rally racing led him to raise an interesting point. If a similar failure occurred while racing, the best case scenario would be a breakage that occurred as close to the outside of the drivetrain as possible; i.e. easier to fix on the side of the road/track with minimal time and tools. Now while that sounds fantastic, if Marks engineered any part of their outer portal hub set-up to be the failure point, while that may mean it’s only a handful of bolts and a matter of sliding a new portal shaft in, they wouldn’t sell any units. Why? Because people would assume they are weak and not up to the task. Designed failure points are a hot button topic and they can either make or break a product’s success.

CONCLUSION
What does this show us? It shows us that nothing is indestructible, but it also shows us that Marks Portal Hubs are bloody strong. Nothing in the portal itself let go, merely the older, outdated long-side rear axle. The $$$$ they have spent on R&D have created a top shelf product that very few people have managed to break. After 90,000km, Steve eventually found the weak link in his set-up (the old first-generation axle that has been replaced with a much stronger, visibly improved version for all 79 portal kits sold now).

Now that begs the question, where is Steve’s new weak link…? Is it his diff centre? Or will he pretzel a driveshaft or crunch some cogs in the transfer? Let us know your thoughts below.