Stub Axle

Submitted: Monday, Jan 19, 2015 at 18:05
ThreadID: 129657 Views:9798 Replies:5 FollowUps:3
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The following post is a copy of one I put on the owners forum last week. I received two replies about the GPS,but no feed back on the stub axles. Thought I'd try here and see what happens. Not sure what to do.

My post is in two sections so will try to keep both short.
Getting ready for our next trip away,up around the gulf. 1st and 'least' important is that our 10 year old Garmin GPS needs replacing. I reckon it'd reached its used by date 10 years ago when we got it from SIM. That's another post for another time ! Can anybody give me info on the Hema HN7 ? Have done some research,and it seems too good to be true. Does anybody have one ?

Next part of my post is about the stub axles. We've done probably around 150000 kms since getting our BT new in 2004 and have been over a lot of serious corrugations,but have always travelled accordingly. Meaning,tyres down & slow. However I'm thinking of doing the upgrade to the 60 tonne stub axles that Simplicity Suspension engineered some time ago. Apparently it's about $330 per axle,but from what I've read on the BTi Forum,the end cost could be a lot higher depending on what else they consider needs replacing. Steve did say on his post that anybody who has had regular maintaince done and has driven to conditions " should " have nothing to worry about. We've always had a service done before every big trip.. In 10 years we've only needed to replace the rubber blocks twice. Wondering if any members have done the upgrade,and what the end cost was ? I've read about welding a chain link to the chassis and so on to lift the arm up if it does happen,but would rather do the upgrade if it's that likely as I'd imagine if one broke it'd do a fair bit of damage.
Tracks n About

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Reply By: AroundAustralia - Tuesday, Jan 20, 2015 at 06:10

Tuesday, Jan 20, 2015 at 06:10
Lawrie, for what it's worth, if it worries you just replace them. If you have done the right thing in the past on the rough then that's ok. I think what has been the real issue here is that owners don't actually see or feel what does the damage. It could have been a pothole or two the tow vehicle didn't hit or a curb you cut fine in a town. Just my view.

Wendy & Michael

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Reply By: Rob & Yvonne - Tuesday, Jan 20, 2015 at 19:07

Tuesday, Jan 20, 2015 at 19:07
I have been using HEMA navigators for some time now. I originally (2005) used a car computer running OziExplorer and then switched to a HEMA HN5 as the car computer proved to be unreliable in rough terrain. I have had a HEMA HN6 for a number of years now and I am very happy with it. (Almost identical to HN7 in functionality)

The HEMA GPSs all run OziExplorer and to take full advantage of this powerful application, you should purchase OziExplorer for your PC. This will allow you to plan trips on a large screen to create waypoints, routes and tracks which are then easily transferred to your HN6 or HN7. This is not complicated at all.

The HEMA GPSs have both Street and Off Road GPS applications. The Street app (iGO) is also good in my opinion.

HEMA are excellent with their service, I have had them send me a replacement unit to Kalgoolie on one occasion.

Send me a PM if you want more information.


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Follow Up By: MarkB - Wednesday, Jan 21, 2015 at 07:01

Wednesday, Jan 21, 2015 at 07:01
We use the Hema HN 6 as well and have to agree that it is a great GPS. Comes loaded with Camps 7 and Caravan Parks Aust Wide . This feature makes it so easy to find and get to camp sites, caravan parks and dump points.

Before this we had the original Hema which was also good . We sold it easy on EBay - they seem to hold their value!


Mark and Chris

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Reply By: Spirit Gypsys - Wednesday, Jan 21, 2015 at 07:00

Wednesday, Jan 21, 2015 at 07:00
Hi Lawrie, we have a 20 2001 van which we've lived in full time for the last 10 years and have been on the worst of them
Always been very particular about tyre pressures etc. but have still broken 2 axles
One (rear left)was reversing into a park site in Jabiru, the axle had been half broken for some time.
2nd one was Oct. last year , 80k west of Longreach after the Plenty in a bad way,(bulldust holes over the bonnet of the Troopy)
Front right this time on bitumen luckily as it slid down the road on the spring end til I stopped it as it hit the dirt and didn't do any damage.
Again the axle had been cracked halfway for some time.
It would be an entirely different matter on dirt, Things could get very wobbly I think.
Maybe the chains idea is worth considering even if if would limit wheel travel but only in very extreme cases.
I check for cracks with that head crack spray when I do the bearings (10-15000k)
and I'm going to carry a spare axle stub now so as a last resort I could have it welded on the arm anywhere in the bush that has a reasonable welder.
I believe it's just metal fatigue like our 3.5 ton hayman reese 50mm square tow bar tongue which broke outside Winton just before the axle.
It too had had been half broken for some time. (probably the same bulldust holes)
The hr box is only 3 mm wall thickness. Mine is now 8mm
AnswerID: 588338

Follow Up By: Tracks n About - Saturday, Jan 24, 2015 at 03:19

Saturday, Jan 24, 2015 at 03:19
Thanks for your replys. Know what your saying about the Plenty. Took us three days to travel over it in 2008. Though not as bad as the Tanami in 2010. 5 hours to do 30 kms one day ! Took nearly a week to do the track. One thing about the slow travel is that you get to see more for sure.
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Reply By: Tassie Bushies - Thursday, Feb 19, 2015 at 22:47

Thursday, Feb 19, 2015 at 22:47
Hi Tracks n About,

Put in a search - owners forum - for "Broken Axle" covering the date 19.10.2014 the post number is 9609
Regards Peter.

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Reply By: MiJule - Friday, Feb 20, 2015 at 03:55

Friday, Feb 20, 2015 at 03:55
I saw your post about stub axles but have refrained from posting so far for fear of being tarred and feathered by the general membership. As my views are a little different from most.
Firstly, broken stub axles on bushtrackers are far from rare. We have personally witnessed a number, even though we haven't had our van very long. The fact you have reached a high mileage without any breakages would indicate you have indeed operated the van in a very responsible manner.
The cause of the breakages relates back to the high frequency vibration generated by the short heavy spring without any form of damping on the Simplicity Suspension. This vibration is essentially a massive amount of energy thrashing around under the van. Unrestrained energy in any form will always take the path of least resistance. Some of the energy goes up into the van via the pivot blocks and some back down to the ground via the tyres. The stub axles are simply the weakest link in the chain of constant metal fatiguing vibration. I think you will find that unless there has been some sort of massive impact which simply shears the whole thing the vast majority will have tell tale signs of metal fatigue which are very visible in the form of dark areas, sometimes with rust in them and the last bit to break has a shiny crystalline surface. Classic metal fatigue. In your situtation I think you would be well advised to replace all four stub axles. At your mileage there is inevitably significant fatigue already occured and it's just a matter of time, probably a short time, before they break. Sorry to be the bearer of bad and expensive news. BT now offer 3 types of suspension - leaf, coil & air. The leaf in my opinion is the least suitable and most damaging of the 3 choices. The leaf suits the manufacturer as there is no owner input and is virtually bullet proof for the warranty period and some years after. To describe it as the best off road suspension is simply to deny the laws of physics known for 400 years.
If anybody wishes to gain a better knowledge of what happens when a suspension is undamped, reading Collyn Rivers articles in the Caravan & Motorhome (CMCA) books section, under articles. The article in question is called "Why wheels fall off". The article is principly about the title but gives good information on the effects of undamped suspension.
In my working life I was professionally involved in vibration testing of heavy equipment and have a smidgen of knowledge about the effects of vibration. For all you members that have been sold the standard suspension, believing it was the best, please don't beat me to death.
Honest, I didn't do it!!!
AnswerID: 588340

Follow Up By: braggy - Tuesday, Mar 03, 2015 at 20:33

Tuesday, Mar 03, 2015 at 20:33
I have had suspension breakage as well, even with lowered tyre pressure and reduced speed.

The unsprung weight and no dampering,may not be the only issue.

I am now looking at the way the wheels fit, "lug centric" on the Dexter drums as the hub is not designed for them to fit "hub centric".
If they don't centre properly they will shake and vibrate, and cause fatigue somewhere, Seems that lug centric should be torqued up while wheel is still off the ground, to have any chance for the tapered nuts to work. Even then the wheel studs are not designed to take the load at 90 degrees,they are only designed to hold the wheel back onto the drum.

The Dexters may well be big truck style, but ever noticed how many wheel nuts/studs on those truck wheels.

Hub centric V Lug centric

Cheers Ken
FollowupID: 856360

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