GVM upgrade

Serious question: How does the fitting of the yellow mine nut indicators help?

Years ago I had my Kimberley Kamper's wheel bearings repacked while undergoing the annual Rego inspection and it transpires the mechanic used a rattle gun for when I arrived at my destination I found that 5 of the 6 wheel nuts had sheared off. He blanched a few weeks later when I showed him the remains of the studs. Hat to think what could've happened if the 6th sheared and the KK flipped into an oncoming car or whatever.

No.and for the record this isn't my vehicle. Just one that got towed in.

Ivan
It read as though it was your vehicle, otherwise we will never know who will accept responsibility for anything?

The perpetrator of the overtightened studs will never be found or held to account.

Finished building my caravan we did our maiden trip 250km return. Then I checked everything. ..except the wheel nuts and bearings.! Was distracted.

Second trip 400km from home heard a commotion- yep passenger side wheel of the van came loose and nearly fell off which would have made a mess.

Rim was ruined, used the spare, went to rob the other wheel of one nut and found that wheel was loose also.

Is a single axle leaf spring single drop axle mech brake set up. Checked with the trailer supplier of correct torque settings - 110nm. Torqued up a new rim and new studs/nuts...whoa...110nm is a lot more than I'd normally tighten with a cross brace!

Lesson learned. 5 new studs and rim wasnt very costly.

Frank - Dirt and paint between mating surfaces under tension is a big no-no, and these two "foreign products", most certainly crush after serious amounts of use, and that then releases the correct tension on fasteners.

When I ran many bulldozers, and we had to replace track shoes, it was imperative that the new paint on the new track chains, was burnt off the links, and the link and track shoe mating surfaces wirebrushed, prior to installation of the track shoes.

Failure to do so, would soon see numerous loose track shoes and the resultant damage caused by wallowed-out bolt holes, which would then make it more difficult to keep track shoes tight in future.

Cheers, Ron.

Splits - No, the later model Landcruisers using the 14mm, 5 stud wheel hub, do have problems with wheel stud breakage, particularly when operated at maximum gross load levels and on unsealed roads - and also where correct wheel stud tightening procedures are not followed.

My nephew runs a large earthmoving operation and owns a number of late model Landcruiser utes fitted out as service vehicles, and these operate under maximum loads regularly.

He's already had two Landcruisers lose rear wheels due to wheel stud fracturing - and lost another Landcruiser ute (a complete write-off), which was rolled. I personally suspect stability problems with the narrow rear axle, coupled with heavy and high loading, were the reasons behind the write-off - but no-one has investigated the rollover crash, because no-one was injured.

Both Landcruisers that lost rear wheels did so with no other damage, apart from some brake damage.

It's interesting to see, that the heavy trailer manufacturers insist that the wheel stud arrangement with the best load-carrying capacity, is the old 6 stud Landcruiser arrangement.

Cheers, Ron.

Ron,
Do the studs break on the threads? This would be the main stress point.
A way to rectify that, is machine a groove under the diameter of the root of the thread. The stud will then stretch at the groove and have less chance of breaking.
Especially if they don't use the rattle gun.

Good Luck

Bill

Bill
How does reducing the strength of the stud by reducing it's cross section make it safer. Isn't it failing because the current cross section is being reduced and the grain structure changed by stretching?

B1B2 - Yes, it appears they break at the threads, usually, but not always, near the axle hub.

Personally, I'd be sourcing higher quality studs with a greater tensile strength than the originals.

Mick O has been onto it, and has an excellent article on his "fix".

Mick O's custom-made high tensile wheel studs for Landcruiser

There's some good comments on Micks article by knowledgeable people.

Cheers, Ron.

How many people carry a full set of wheel studs? I will be from now on. I only carry a couple ATM

.
Only the skinny ones for the rear left wheel Ivan.
The others are OK and never break. lol

On any vehicle the left rear wheel is the most stressed as it often carries MORE load than the opposite side due to road camber. Steering input also creates more stress as the weight is transferred from Rear RHS to LHS wheel on that camber. Most people drive around RH corners much faster than when negotiating left turns. Therefore load/stress transfer is much more. That LHR wheel also receives much harder hits from corrugations and potholes as a result if a number of factors.
That wheel is usually the one where bearings fail more often as well.
It isn't surprising at all that it will be the wheel involved in the most issues. Be it tyre, studs, wheel failure or bearing failure.

Another line of thought...L/H side wheel nuts undo in the same direction as the wheel (normally) rotates.
Under torquing of the nuts could, due to rotational vibrations, cause the nuts to loosen sufficiently for stress shear of the studs to occur.
I recall an early model Valiant with L/H threaded wheel studs on the near side wheels.
mike

No, the later model Landcruisers using the 14mm, 5 stud wheel hub, do have problems with wheel stud breakage, particularly when operated at maximum gross load levels and on unsealed roads - and also where correct wheel stud tightening procedures are not followed.
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I was not aware of that but it is still hard to believe when you look at the amount of testing these things are put through.

There was a story on a new Hilux 4x4 about five or so years ago in the monthly NRMA journal. It said the car was tested for one million ks with 650,000 of them in Australia. Some of the prototypes did 150,000 while they tried and succeeded to break others within 20,000. It also said Toyota spends one million dollars per hour world wide in research and development.

Despite all of this we have one breaking its wheel studs in only 600 ks. I still think there is more to it than just wheel stud design. That should have shown up in the first few days of testing in the bush. In this case I still think the load it was carrying has played a big part.

I know that Toyota, and a few other manufacturers that I have asked on their customer information service, have towing weight restrictions in off road conditions. One of them said their 3500 kg maximum comes down to 1500 kg off road.

I have not asked about carrying restrictions because I always keep my cars well below the maximum, even on sealed roads, but I would be surprised if they did not have them.

Splits, the manufacturers do testing on wheels and hubs and studs, but with basic designs.

Then comes variations on the design - such as alloy wheels, with longer studs, and wider track - then aftermarket wheels, with additional variations of offset and centre hub design.
Then owners put heavy trays and canopies on, and extended trays. Then they load them up to maximum GVM - and then ask for increased GVM.
Then they drive them like there's no tomorrow - on roads that are heavily corrugated. It all gets a bit much for the original design.

The most concerning thing I see today is extended trays on dual cabs. Now, I know the vehicle design regulations say you can have up to 60% of a wheelbase length, in tray length, behind the rear axle.

But I've seen some horrifying-looking lengths of trays hanging out the behind the rear axle of dual-cab Landcruisers just recently - and I believe these setups need to be banned.
I've spotted several near-new dual cab Landcruisers sporting trays that looked to me, like they were around 2.2M long. That's an accident just waiting to happen, IMO.

It's obvious tray builders are taking the regulations to the maximum - but I believe those tray length regulations need to be seriously looked at in todays world, where dual cabs with long trays are proliferating.

IMO, many of these long trays are imposing serious weight loadings and side thrust on the rear axles of these dual cabs - to the extent that I'm personally of the opinion, that they're downright dangerous - as regards unstable handling when fully loaded, and as regards the excessive loads they're imposing on rear axles, rear wheels, and their wheel studs.

Hitch up a 'van or big trailer to these outfits, and the problems can only get worse.
Add in the narrow rear axle of the Landcruiser, and the side thrust loading on the rear axle, wheels and wheel studs, increases, as compared to a rear axle that is the same width as the front. It's a simple leverage problem.
More overhang, more problems related to poor handling when fully loaded, more swaying, more steering "twitchiness", and more back-and-forth stresses on the rear axle.

Cheers, Ron.

Ron

I agree with your comments about the aftermarket industry. They have a lot to answer for with many of their products. I think they lull many unsuspecting owners into a false sence of security.

As for narrow rear axles, many car manufacturers have done that. I think from memory the 504 Peugeot that I owned for ten years had a wider front track. They had an excellent reputation for handling unsealed roads. I can remember the late motoring journalist, racing team owner and Australian touring car champion David MackayMACKAY writing a list in a Sydney newspaper of about ten different driving situations and listing the best car for each one. He had Peugeot on the list for off road work.

It is not the width of an axle that causes it to break. If it has been designed to do a particular job then it will do it no matter how wide or narrow it is. If an assortment of different wheels (genuine, not aftermarket) are available as options, then they will have been taken into account when the axle was in the early design stages.

Toyota has been using this rear axle for years and if there was a design fault in it they would have fixed it long ago. I have worked for three Toyota dealers and I can assure you they don't muck around when something as serious as this comes up.

This car that we are discussion now remings me of a customer at work with a new 60 series that was wearing its front tyres unenvenly. He would not accept that his oversize wheels and tyres could be responsible for it. We arranged for him to meet a Toyota rep. This rep was the head teacher at Toyota's technical training centre for commercial vehicles in Sydney.

He arrived early and we were talking to him in the service office when the owner arrived. He walked to the door, looked at the car from a distance then turned and came back inside. He was not the slightest bit interested in looking at a non genuine part that the owner claimed was causing a problem. He told him if he comes back with uneven wear on the original wheels and standard specification tyres then he would look into it.

I would not be the slightest bit surprised if Toyota has already looked into this broken stud problem and found there is nothing wrong with them if the car is standard and being used within its design limits.

Splits, I know and understand that many other vehicles had, or have had, narrow rear axles, and still performed admirably.

The major difference between those (nearly all) passenger vehicles, and the current Landcruiser dual cab ute, is that none of those other vehicles were rated to carry a tonne in load - and carry that tonne of load at a high level.

The Landcruiser tray is high to start with - you add a heavy load with some height to it (let's say, an earthmover transmission, or a diesel engine, both on a support stand) - and you immediately have a high, heavy load, with overhung tray leverage on the chassis - all adding up to a major degree of vehicle instability, and a major load on the rear axle, rear wheels and rear wheel studs.

Here's a real-life, drive review of a single-cab Landcruider traytop from 2016. Note how the reviewer comes down hard on the shortcomings of the narrow rear axle.

Landcruiser Workmate review - 2016

Cheers, Ron.

Ron

His criticism was on the axle's handling characteristics, not breaking wheel studs. I agree with him when he said it was cost cutting but all of these volume selling popular cars are built to a price and a work ute is no exception.

The car we are talking about has a GVM upgrade. That means it has been taken up legally to the maximum capacity of the axles. My Hilux has a GVM of 2500 kg but the maximum capacity of the axles is just over 2700 kg. This Cruiser now has nothing left in reserve. You will most likely get away with it if you stay on good sealed roads but unsealed or bush tracks is a totally different story. This is why manufacturers recommend reducing both carrying and towing loads in off road situations in accordance with the conditions.

In the edition of the 4x4 Australia magazine that featured the bent chassis story, it said the towing capacity should be reduced in off road conditions. They then praised Land Rover for recommendeing it. The editioral said the carrying capacity should come down by around 40%.

During my time in both the Army and Air force, I noticed carrying capacities were down by around 50%.

I still believe the broken studs problem lies with the aftermarket and the owner, not the car manufacturer.

That is far too common on caravans. It looks like there are no shock absorbers on it except for those crude little rebound springs.

I remember Collyn Rivers writing about the lack of shocks in one of the articles on his web site about the Bedford truck that he drive twice across Africa. That drive involved suspension development on different road surfaces. The said he found undampened springs had thirty five times more rebound force ramming the wheel back into the road than the same springs with shock absorbers.

All those little things do is squeese the spring leaves together to create some friction on rebound but it is nowhere near enough.

9900Eagle
I have always put it down to rattle guns for them being tightened with a breaker bar.
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Incorrectly adjusted rattle guns and breaker bars have definitely caused more than their share of damage.

I noticed during my time working in the service office of new car dealers that very few owners read the vehicle hand book. In the book for my Hilux it says to tighten the wheel nuts as tight as you can with the tool provided then as soon as possible set them to the correct tension with a tension wrench. It also says never use a hammer, a piece of pipe or your foot on that tool.

The little wheel nut tool they supply with the car looks far too small so most buyers buy a breaker bar and here lies a major problem. To my way of thinking, that little tool has been designed so the vast majority of owners can undo a correctly tensioned nut with it but they can not significantly overtighten it with it.

I suppose that is about as much control a car manufacture can have with wheel nut tension.

Splits you've got it in one , that angle and length of the bar is in fact designed to give the 'almost' correct tension of the wheel nut for that particular vehicle make and model , adding an 'extension' or using a foot generally means the socket slips off the nut ...most people then swear *^#! it and over tighten the nuts ....lots of R&D went into the 'original' by the vehicle manufacturer and their 3rd party suppliers of the nuts and studs ... but NO , we all just take it for granted that we know better and over tighten...