Everything you always wanted to know about LBJ bolts

[phattyduck]

I can tell you that loctite is not the best way to ensure that.

How crazy do you want to get:

Stage 8 CV Axle Locking bolts - E153 Axles
– Prime MR2

Something like that would be cool... but then you'd get back to worrying about the quality of the bolts again too.

(those inner axle bolts on MR2s, along with Porsches, Corvettes, etc. are always a risk - they like to back out then break)

-Charlie

 

[theesotericone]

Agreed, there's lots of margin to increase preload above what Toyota recommends. Not much of a downside to it, either. And the bolt will fail in tension way before the knuckle threads will yield, provided you have 4 or more threads engaged.

Regarding bolt failures in the field, I've seen a FB post of someone having that happen, but it's not clear how they know it was a shear, rather than tensile, failure. Any chance you have pictures or remnants of failed LBJ bolt joints?

I'm having a bit of a hard time seeing how the joint can fail in shear as long as the bolts are tight. In addition to the friction force, there are two shear cones on the LBJ that should take the shear loads. What happened to these cones to let the bolts fail in shear?

My suspicion is that the bolts start to back out due to the heavy loads you describe, and allow gapping to take place. Once the joint gaps, the impact loads lead to oscillating loads in the bolts, the shear cones are no longer effective, and the bolts do in fact fail either from shear or tension.

That's why I personally think that the most critical thing in the LBJ bolts installation (aside from preloading to the right load, around 10,000 lbs or more) is to ensure the bolts don't back out. And after way too many years in the aerospace industry, I can tell you that loctite is not the best way to ensure that.

I'll search around and see if I can find a few old bolts. I don't think I took any pictures because I'm usually busy field welding the LBJ to the spindle. BTW, the welded LBJ/spindle combo lasted for over 6K miles before I replaced them. For anyone wheeling hard. Weld that shit. lol

You could very well be correct about the mechanism of failure. I do red loctite the bolts and I do check them often given how many I have broken. I only check them by eye though. It's entirely possible they back out or stretch just enough to allow the centering ring to get clear of the LBJ. The centering ring/shear cone is slightly wallowed after I have a failure but certainly not sheared clean off.

 

[JZiggy]

Just wanted to bump this thread since it deserved more exposure. If you look a couple of pages back at the data Leon created for us there is a compelling case to upgrade to the 01-02 OEM black bolts.

 

[octanejunkie]

On FB yesterday

What's a torque spec?

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[Bad Luck]

On FB yesterday

What's a torque spec?

Sent from my Pixel 4 XL using Tapatalk

Looks like they went to 7-8 ugga-duggas. I wonder what the final torque on those bolts were

 

[Spiker Engineering]

On FB yesterday

What's a torque spec?

Likely someone torquing the Black bolt to 59 ft-lbs, a pretty common blunder.

 

[Spiker Engineering]

Looks like they went to 7-8 ugga-duggas. I wonder what the final torque on those bolts were

I'm hoping to get to the destructive torque tests either this week or next!

 

[JohnMc]

What's a torque spec?

Keep on tightening until it starts to get looser again, then back off 15 degrees and let the next person worry about it.

 

[jross20]

So do you guys think it would be worth it to upgrade from the red bolts to the black ones and torque them to 37 (or whatever it was).

I bought the red ones based on that old information I linked a while back. I figure the reds at 59 should be fine but now I'm curious about the black ones... It doesn't matter if you use that dust cover thing? Does that dust coverer fit on all years?

 

[Bad Luck]

So do you guys think it would be worth it to upgrade from the red bolts to the black ones and torque them to 37 (or whatever it was).

I bought the red ones based on that old information I linked a while back. I figure the reds at 59 should be fine but now I'm curious about the black ones... It doesn't matter if you use that dust cover thing? Does that dust coverer fit on all years?

Dust cover fits all years as long as you are using the corresponding bolts for it. I wouldn't worry about it until it's time to change them again. There aren't as many cases of the lower ball joint bolts breaking/shearing as there are lower ball joints separating. Bolt shearing seems to mostly be an issue with rigs that are playing in the big rocks that see a lot of extra stress on those bolts from wheeling. I plan on changing bolts if I change the lower ball joint or need to separate the lower ball joint from the spindle.

 

[octanejunkie]

I plan on changing bolts if I change the lower ball joint or need to separate the lower ball joint from the spindle.

I've unbolted the lower ball joint from the spindle about five times already since installing my ARB bolts, each time torquing them to 54 foot pounds per ARB's recommendation for the bolt.

I've measured them with a caliper against the brand new uninstalled ARB bolt each time I've removed them and measured no discernible stretch / change

I guess the real question is, when do you cycle them out??

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[Bad Luck]

I've unbolted the lower ball joint from the spindle about five times already since installing my ARB bolts, each time torquing them to 54 foot pounds per ARB's recommendation for the bolt.

I've measured them with a caliper against the brand new uninstalled ARB bolt each time I've removed them and measured no discernible stretch / change

I guess the real question is, when do you cycle them out??

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That's a good question. I'm sure that would vary depending on the bolt used. I was more of stating along the lines of I won't go out of my way to change the lower ball joint bolts until I already have the bolts removed.

 

[jross20]

Dust cover fits all years as long as you are using the corresponding bolts for it. I wouldn't worry about it until it's time to change them again. There aren't as many cases of the lower ball joint bolts breaking/shearing as there are lower ball joints separating. Bolt shearing seems to mostly be an issue with rigs that are playing in the big rocks that see a lot of extra stress on those bolts from wheeling. I plan on changing bolts if I change the lower ball joint or need to separate the lower ball joint from the spindle.

Maybe this is a dumb question... But is there enough clearance with a dust cover for those of us who have a "mid travel" setup? i.e. maxed out travel with a stock lower arm.

I've got my next ball joints and a set of the red bolts sitting in my storage room to be used in the next 10k miles or so... So it got me wondering if I should go ahead and swap to the black boots... Hmmm

 

[Bad Luck]

Maybe this is a dumb question... But is there enough clearance with a dust cover for those of us who have a "mid travel" setup? i.e. maxed out travel with a stock lower arm.

I've got my next ball joints and a set of the red bolts sitting in my storage room to be used in the next 10k miles or so... So it got me wondering if I should go ahead and swap to the black boots... Hmmm

That's a good question that I don't have the answer for. You don't need the dust cover to use the black bolts which is what I'm planning on next time the lower ball joints bolts get removed. If you haven't installed them yet then I would get the black bolts.

 

[Spiker Engineering]

I've unbolted the lower ball joint from the spindle about five times already since installing my ARB bolts, each time torquing them to 54 foot pounds per ARB's recommendation for the bolt.

I've measured them with a caliper against the brand new uninstalled ARB bolt each time I've removed them and measured no discernible stretch / change

I guess the real question is, when do you cycle them out??

"Use the data, Luke!" :lightsaber:

Basically, at the initial installation of ARP bolts at 54 ft-lbs you are going to have about 15% less preload than you would with the red bolts at 59 ft-lbs (7385 lbs vs 8691 lbs). If it were me, I'd do all I could to install these bolts to the ~9,000 preload that Toyota is recommending, not at 15-20% lower.

Then, if you start reusing the bolts, you should be bumping up the torque with each reuse - 10% more at first reuse, 15% more at second, 20% more at third (for ARP bolts). Otherwise you'll end up with less than 6,000 lbs of preload by the third reuse.

As for length measurements of the bolt, you should not expect any stretch with reuse, unless you overtorqued (yielded) the bolt - you would need to torque it to over 100 ft lbs for that to happen. So the fact that you are not seeing any stretch tells you that the bolt hasn't yielded (which is good), but it doesn't tell you anything about its degradation in preload vs torque relationship.

I didn't cycle the bolts beyond four cycles, so I don't know if at some later point you'll hit a cliff and the relationship will degrade more drastically - I might do that just for fun, it doesn't take long.

 

[og80gt]

Great timing! I just ordered LBJ's with green bolts, but I guess I'm going to order the black bolts with washers now! LOL

Thanks for the research!!!

Also, I just noticed you're near me! We should meet up sometime....

Jason

 

[jross20]

I'm hoping to get to the destructive torque tests either this week or next!

Any update on the destructive tests? Not trying to rush ya, just curious
:madgrin:

 

[Spiker Engineering]

Any update on the destructive tests? Not trying to rush ya, just curious
:madgrin:

I ran out of bolts . I ordered some more, they just arrived - so the plan is to break some bolts next week :thumb:

 

[jross20]

I ran out of bolts . I ordered some more, they just arrived - so the plan is to break some bolts next week :thumb:

Oh snap. You should have messaged me; I would have gladly bought some to help out!

Alright though, now I'm excited

 

[Spiker Engineering]

The destructive tests are done, quite a good workout if I do say so myself.

I need to do some more data reduction, but one thing I can say already is that there will be a BIG surprise for you all (I was surprised too).

Just a teaser for now of the bolt "bloodbath":