Torsion Bar Adjuster is Broken (1 Viewer)

[AimCOtaco]

Anybody break a Torsion Bar Adjuster Arm before? I've been cruising around here for years and don't recall seeing one / can't find one.
We had this one let go yesterday on super easy terrain (quick shot, view through access in Slee belly plate).

I'll replace it but wanted to see how common a failure it is? I'd started hearing something of a clunk from the front end but had not been able to narrow it down.
This failure looks like a fast break (no rust on the break yet, maybe a crack started on the low side there) and I'm concerned it may be a symptom of something else like the frame side LCA bushing allowing fore/aft motion of the T-bar perhaps.

My wife was out with the truck and heard it go bang while moving over smooth dirt, she said it sounded like a rock thrown up into the frame or something but without any rocks around.

Thanks all,

 

[MongooseGA]

I've not seen it before, either.

Did she notice the truck handling or riding any differently on the way home? Curious if it how much tension the TB still has on it, if any.

 

[Trunk Monkey]

Haven't ever seen it on the adjuster end. I know a couple Aus companies make reinforcement plates for the control arm end for a similar type of break.

 

[FxFormat]

Interesting, never seen that break either, your truck isn't that rusted. Looks like the arm isn't that expensive

Toyota Land Cruiser Torsion Bar Adjusting Arm (Left). Suspension - 4810860010 | Passport Toyota, Suitland MD

Torsion Bar Adjusting Arm (Left). Suspension, Brakes. Toyota Land Cruiser. Genuine Toyota Part - 4810860010 (48108-60010). Ships from Passport Toyota, Suitland MD

parts.passporttoyota.com

 

[AimCOtaco]

The tension is all gone, she rode home on the bump stop. Less body roll in the canyon, and a slight lean

Noticing @Trunk Monkey had posted I expected to come back to multiple links to missed threads Thanks for confirming that this is indeed on the rare side.

Ordering parts now and will do a thorough inspection of everything related.

 

[cjmoon]

I have what you need if you haven’t found it yet. Kept from a part out.
Pm me.

 

[hickuptruck]

Woaw! I was just inspecting visually from underneath 2 weeks ago to check if there was any cracks in that TB area because I've got a small clunk going over road imperfections

 

[AimCOtaco]

Looks like a simple fatigue break to me... maybe a small material defect involved as seen as the corrosion lines. Looks like there was an old crack at the edge that's corroded but then there are a couple more corrosion stripes in the fatigued area.

Mating side, still on truck:

Thanks a lot for the parts offer! I did order new stuff from Toyota and will be happy to go new here given what I've found.

I'm still not 100% convinced that there isn't some odd loading going on here but I haven't found it so I'm leaning toward simple fatigue over a long hard life. Truck has over 250k miles on it, is built heavy, and wheeled fairly hard. I was happy the snap action seems to have loosened up the T-bar splines so pulling the rest apart should be fairly easy. The adjuster bolt was in fine shape and removed without tools so not much corrosion or stretch going on there, I'm going to replace the adjuster, bolt, and both half round thingies to be all new here and rolling with some spares.
I'm tempted to relieve spring tension on the other side and see if the cross member insert where the adjusters mount has any slop, it looks to be mounted on two bushings so I may be able to crank around on it an see if there was any play happening there but it all LOOKS fine and I've never heard of problems there either.

... should be back to breaking things and wondering about strange noises real soon!

 

[IndroCruise]

Here are few stories from another part of the world -- the stories at the link relate to very arduous outback conditions in parts of Australia, especially where corrugations (washboards) are involved over long distances.

Toyota 100 series IFS Torsion Bar Mounts

$$$$$$$$This is the result of the Torsion Bar Bracket breaking. It is a lot more common than Toyota would like you to believe. If you drive this model vehicle fully laden a lot of kilometres on corrugated roads then this is waiting to happen too ...

www.exploroz.com

Fatigue cracking on the front end of "100 series" with IFS is a well-known problem, both at the torsion bar adjuster and also where the torsion bar meets the Lower Control Arm. The more rigid suspension on "80 series" and "105 series" is much tougher.

The failures usually are the product of many, many cycles of up-and-and-down loading/unloading of components as the suspension works hard in tough conditions, amplified by heavy loads. The failure mode is classic fatigue failure -- slowly develops over a long period of time (years) as the steel work-hardens, crystalline structure changes, cracks initiate from some minute imperfection, then propagate slowly until eventually the amount of steel still intact is too small to carry the stresses and a point of final, sudden failure is reached.

Our vehicles are13 years old (2007) to 22 years old (1998) with hundreds of thousands of kilometres (or miles) travelled, some of them loaded beyond the hopefully conservative recommendations of Mr T -- see attached pic which is an extract from my 2006 Owner's Manual. It is inevitable that more and more of these vehicles will have 'fatigue' experiences as time, kilometres or miles, and 'cycles' go by.

The upshot is to try to observe and rectify emerging problems early with inspections and/or crack testing and remediation rather than deal with recovery on the trail. I do not think that the unhappy experience of @AimCOtaco is a "one-off" -- it is just one that he has been kind enough to bring to attention and it is a warning to us all.

There are after-market fixes -- but take care -- as each weakness in any structure is strengthened, it becomes necessary to look for the next-in-line weakness!

For all of that, the evidence is that the "100 series" vehicles even with IFS are wonderful, tough, longlasting units -- this is just one more thing to add to the maintenance program!

 

[ramangain]

Do you have stock or aftermarket torsion bars?

 

[2020 Rocks]

Looks like a simple fatigue break to me... maybe a small material defect involved as seen as the corrosion lines. Looks like there was an old crack at the edge that's corroded but then there are a couple more corrosion stripes in the fatigued area.

View attachment 2442982View attachment 2442983

Mating side, still on truck:
View attachment 2442985

Thanks a lot for the parts offer! I did order new stuff from Toyota and will be happy to go new here given what I've found.

I'm still not 100% convinced that there isn't some odd loading going on here but I haven't found it so I'm leaning toward simple fatigue over a long hard life. Truck has over 250k miles on it, is built heavy, and wheeled fairly hard. I was happy the snap action seems to have loosened up the T-bar splines so pulling the rest apart should be fairly easy. The adjuster bolt was in fine shape and removed without tools so not much corrosion or stretch going on there, I'm going to replace the adjuster, bolt, and both half round thingies to be all new here and rolling with some spares.
I'm tempted to relieve spring tension on the other side and see if the cross member insert where the adjusters mount has any slop, it looks to be mounted on two bushings so I may be able to crank around on it an see if there was any play happening there but it all LOOKS fine and I've never heard of problems there either.

... should be back to breaking things and wondering about strange noises real soon!

there are worse things you could have snapped that is pretty crazy how is snapped so sheer on both sides

 

[abuck99]

Thats a first reported failure I've seen (here). Definitely something to keep an eye on with heavy built rigs that get wheeled- (or Jumped.... aahem Lee ) 48107-60010 is a spendy little part. Might include the adjusting bolt as well if that's been stretched over the years too. Looks like PS has the "nice price". Thanks for posting Andy

 

[IndroCruise]

Do you have stock or aftermarket torsion bars?

My vehicle has still has the OEM torsion bars for AHC with 1HD-FTE turbodiesel. The adjusters were wound clockwise to bring the front AHC neutral pressure back to about 6.7Mpa after the full ARB Deluxe Bar (see avatar) was fitted 5 years ago. Neither re-indexing nor stronger TB’s have been necessary so far. The additional brackets were fitted to both LCA’s at the same time, also by ARB. So basically the TB’s and the anchors at each LCA and the rear TB anchors are carrying the additional weight of the ARB Deluxe Bar plus any added load carried by the front wheels. KING KTRS-79 rear springs keep that area under control. This 2006 vehicle has had an easy life, only 209,000 kilometres (130,000 miles), but the post from @AimCOtaco – thank you -- also has reminded me of the local experiences of others (mainly heavy LC100’s with IFS but non-AHC). So I am looking more closely at the condition of the brackets which anchor the rear ends of both TB’s and house the adjusters, especially with the additional weight of the ARB Deluxe Bar (no winch) swinging on the front of my vehicle. AHC torsion bars are lighter than non-AHC torsion bars.

 

[Yspen]

I am aware of two cases where the bracket broke

Both cases it happened in cars that were heavy laden . One on a trip in Botswana and one in Namibia.
By no means a common occurrence.
A few of my fellow 100 series owners here have strengthened the bracket by welding a steel plate onto the sides of the bracket. It is not my intention to do the same - rather keep GVM low

 

[hickuptruck]

When I did AHC delete, I was def on the fence for getting a new set of adjusters but budget was running low seeing these were about $150 USD each. So I skipped out on them, but I did use a torch on them to get the TB out. Do you think the heat from the torch might have changed the crystalline structure and sped up fatigue in them? Its been years since I took Materials in engineering but you explained it very very well like a materials engineer.

Here are few stories from another part of the world -- the stories at the link relate to very arduous outback conditions in parts of Australia, especially where corrugations (washboards) are involved over long distances.

Toyota 100 series IFS Torsion Bar Mounts

$$$$$$$$This is the result of the Torsion Bar Bracket breaking. It is a lot more common than Toyota would like you to believe. If you drive this model vehicle fully laden a lot of kilometres on corrugated roads then this is waiting to happen too ...

www.exploroz.com

Fatigue cracking on the front end of "100 series" with IFS is a well-known problem, both at the torsion bar adjuster and also where the torsion bar meets the Lower Control Arm. The more rigid suspension on "80 series" and "105 series" is much tougher.

The failures usually are the product of many, many cycles of up-and-and-down loading/unloading of components as the suspension works hard in tough conditions, amplified by heavy loads. The failure mode is classic fatigue failure -- slowly develops over a long period of time (years) as the steel work-hardens, crystalline structure changes, cracks initiate from some minute imperfection, then propagate slowly until eventually the amount of steel still intact is too small to carry the stresses and a point of final, sudden failure is reached.

Our vehicles are13 years old (2007) to 22 years old (1998) with hundreds of thousands of kilometres (or miles) travelled, some of them loaded beyond the hopefully conservative recommendations of Mr T -- see attached pic which is an extract from my 2006 Owner's Manual. It is inevitable that more and more of these vehicles will have 'fatigue' experiences as time, kilometres or miles, and 'cycles' go by.

The upshot is to try to observe and rectify emerging problems early with inspections and/or crack testing and remediation rather than deal with recovery on the trail. I do not think that the unhappy experience of @AimCOtaco is a "one-off" -- it is just one that he has been kind enough to bring to attention and it is a warning to us all.

There are after-market fixes -- but take care -- as each weakness in any structure is strengthened, it becomes necessary to look for the next-in-line weakness!

For all of that, the evidence is that the "100 series" vehicles even with IFS are wonderful, tough, longlasting units -- this is just one more thing to add to the maintenance program!

View attachment 2446584

View attachment 2446586

 

[OwnerCS]

When I did AHC delete, I was def on the fence for getting a new set of adjusters but budget was running low seeing these were about $150 USD each. So I skipped out on them, but I did use a torch on them to get the TB out. Do you think the heat from the torch might have changed the crystalline structure and sped up fatigue in them? Its been years since I took Materials in engineering but you explained it very very well like a materials engineer.

The torch may have accidentally annealed the adjusters.

7 Types of Annealing Explained | MachineMFG

Discover the benefits and applications of annealing and learn about the 7 different types of annealing. Our comprehensive guide will help you get the most out of this essential process.

www.machinemfg.com

 

[IndroCruise]

When I did AHC delete, I was def on the fence for getting a new set of adjusters but budget was running low seeing these were about $150 USD each. So I skipped out on them, but I did use a torch on them to get the TB out. Do you think the heat from the torch might have changed the crystalline structure and sped up fatigue in them? Its been years since I took Materials in engineering but you explained it very very well like a materials engineer.

" ... changed the crystalline structure and sped up fatigue ..."


Mmm -- maybe -- but this would be speculation. What is the nature of this particular steel? How much heat? How long? How uniform? How cooled? Etc, etc.

Whatever of all that, it is difficult to imagine the kind of relatively 'gentle' applied heat mentioned improving microcracks which already have started -- component probably much less than red hot. It is likely that microcracks have long been present. If so, this is beyond the granular level, grain separation already has taken place, and applied heat will cause expansion of the part, induce stresses and accelerate the existing cracking and separation. It may initiate new cracking.

The excellent pictures provided by @AimCOtaco show the striations associated with progressive metal fatigue. The presence of minute rust lines certainly suggest that the cracks, although initially tiny, have been open and active for some time. They have been exposed to air and moisture. There is no visible evidence of 'necking' (or thinning) which is seen when ductile steel stretches in tension and eventually fails due to tensile stresses. Failure due to shear stresses is not visible. Instead we see the progressive and eventually final brittle (not ductile) failure associated with fatigue. The end result may seem 'sudden' but there is nothing sudden about this progressive process.

As mentioned by @AimCOtaco, the outcome is the result of heavy loads, tough conditions and many 'cycles' of stress changes over a long period of time.

It seems likely that the other side of the vehicle will be affected in a similar way because it has been subjected to the same conditions -- but has not got around to failing just yet.

The very good news is that the 'fatigue life' is very long, around 250,000 miles in the reported case. Given that this is not a common failure, fatigue life obviously is even longer in less arduous circumstances of load and operating conditions. However, we should not kid ourselves that it is not happening just because we cannot see it -- worth keeping this area under watch in older vehicles which are being worked hard.

 

[OwnerCS]

I ordered a set with anchor adjusters late yesterday. I will install them in with the new beefed-up suspension.

LCA reinforcements were installed from the first round of suspension enhancements.

 

[OwnerCS]

Got in a set of adjuster arms with the half moons. I will inspect the bolts when swap in these with new TBs.

It is interesting there is a skip in the splines where the white mark is located.

The OEM torsion bars fit tight but there is a small amount of slack between the bar spline and the adjuster.

It will be too easy to separate the bar from the adjuster should I remove the bar at some point in the future.

 

[MongooseGA]

Not quite the same issue, but I did discover a similar one myself today. While installing a cross-member for the Asfir skids, it dawned on my the thing wouldn't fit because my adjuster is bent quite a bit forward. Not really sure how that happened in the forward direction, but it's done now.

Glad I caught this thread the other day so I knew it'd be an easy enough fix.