Everything You Always Wanted About Lower Ball Joint Bolts

There can be some problems with stainless in contact with mild steel.

Galvanic corrosion and Bimetallic coupling are two of them.
They can cause an issue where they corrode each other, this can cause a premature failure at the threads, and/or could make the bolt break when removing it.

Anti Seize is recommended ALL OF THE TIME that a stainless bolt is installed in a dissimilar metal. That would change the torque/preload even more than the use of blue Loc-Tite.


I recently had a 3 bolt failure. One bolt held on to keep the wheel on (not sure how that happened, but glad it did).




Not sure which one was the first to break. But I thought it was odd how far up in the spindle the two bolts on the bottom (in this picture) broke off.






Kind of had me reconsidering some of the decisions I've made recently





Now... I get that 37s are adding stresses, and I think I may have taken these bolts out a time or 2 without replacing them. Which is probably the explanation. I thought I was using the highest recommended bolt from this thread, but now I think I'm wrong, because I was not using black bolts. I'm pretty sure they were Toyota Red with blue Loc-Tite.


I think, the way I'm going to approach this... to get the truck back together(for now), is ARP bolts and drill the heads for safety wire. I use safety wire on my leaf spring U-bolt eliminators and it works out well. It would be a little bit more tedious doing safety wire in this location, but worth the added time/effort.

 

Something like these may be a solution on the stainless bolts. They are coated to increase hardness as well as protect from corrosion. They also have rolled vs cut threads. Rolled are stronger and also more consistent for torqueing.

https://www.probolt-usa.com/stainless-steel-flanged-hex-head-m10x1-25mmx35mm-race-spec-lsshx1035fr/




Or these... The expensiver option

 

Interesting, this is one of the first examples I've seen of actual LBJ bolt breakage. Any chance you still have the bolts and the remnants and could send to me to have a look? The bolts that broke deep within the knuckle are indeed an oddity.

 

The bolts that broke off are somewhere on the trail. The bolt that held on... not sure what I did with it. The bolts that are in the spindle... aren't coming out without completely drilling them.

 

Understood. Something very strange happened to those broken bolts, it's a head scratcher.

 

@JTFisherman might have broke his bolts too on the trail. I’ve seen 2 sets break on trucks that were jumped. The ball joints usually fail on trucks that aren’t maintained and bolts usually break on trucks that are off-roaded pretty heavily.

 

That probolt is listed as 316 stainless. hopefully SpikerEng can confirm but the listed tensile strength is 80,000 psi vs 145,000 for a grade 10.9 bolt. I wouldn't hesitate to use the A286 grade he described but I personally would not use 316 for a suspension component. The standard zinc plated OEM bolt seems to hold up well.

And I am quite a fan of stainless. All my drain plugs are stainless etc but none of these are in anyway mission critical.

 

A couple of things here... First of all, 316 stainless is great for corrosion resistance durability (as the Pro Bolt website correctly states), but it is designed for low stress applications. It is by no means a high strength material, probably under 80 ksi, and I would not recommend it for anything suspension related, least of all LBJ bolts. The Pro-Bolt website does not list properties for their 316 bolts, but in general 316 is similar to A4, which is about the same strength as an 8.8 bolt, and is about 30-45% weaker than a 12.9 bolt:

https://monsterbolts.com/pages/metric-bolt-grades

So I would not use 316 bolts for LBJs.

The Titanium option is better, but it is still only a Grade 5 fastener, so similar to 8.8. We're talking ~100 ksi strength. It is great for weight savings and for having pretty coating options, but that is not the concern we're dealing with here.

In contrast, the ARP stainless bolts are listed as having a strength of 180 ksi, which puts them firmly into the 12.9 category. I think that option is going to be pretty hard to beat.

 

Either the black or the stainless ARPs are the way I'll probably go. But I'm still deciding whether or not I'm going to drill and tap the spindle for M12 bolts.

 

The ARP 8740 Chrome moly bolts are a bit stronger than their stainless, but they have very poor corrosion resistance. That's why I'd probably go with stainless.

Good call, I was wondering if that may be a good option. You'd need to look closely to make sure there's enough material around the tapped threads in the knuckle, as well as enough clearance for the larger bolt head/washer at the ball joint. You may want to try socket head bolts.

 

I recently bought the TC uniball conversion. Curious to see how they hold up bolt wise. The indexing in the spindle should help I’d think. Bolts appear to be zinc 10.9’s. Don’t look very special. I’ll see what I can do to break them. Off to a good start since I’ve torqued them two or three times by feel and we aren’t even on the ground yet

 

Ya, I don't like the pictures I've seen of the black bolts rusting. Although, rust isn't as much of an issue out here (West) as it is in the Midwest and the East.

On the other hand, the stainless could react to the mild steel and cause it's own issues. Those issues can be resolved with anti-sieze but I'm not really wanting to go that route on LBJ bolts. As discussed before, anti-sieze and thread lockers change the torque.

That's my dilemma right now.



As far as drilling and tapping the spindles. The holes closest to the wheel (the blind holes) have enough meat on them for sure. Even the ball joints themselves, being drilled for the locator sleeves to be pressed in them are opened, mostly, to around the size hole for an M12 bolt. It's the holes away from the wheel (the two forks) that I'm deliberating over. They seem like they have enough meat around them to work with M12. But I'm considering building them up by welding some plate to them.

 

LOL... Those are the LBJs I'm running.

 

Oh damn I thought you had OEM haha well that’s a big disappointment…guess I’ll be tuning in for a solution and maybe contributing to something if I can.

 

A theory I have about the inner bolts (closer to the wheel) breaking so far up in there is:

There is no thread engagement until the bolt is so far up in that hole due to the alignment sleeves on the Lower ball joints. I believe the bolt broke at the spot when the bolt threads begin engaging the spindle.

 

I could see that. Surprised with the indexing it lets these bolts shear. Would think the sleeves would have some defect. How do yours look?

I wonder if upsizing only those bolts would be enough since there’s not a lot of meat around the others.

 

All (legit) LBJs I.E. OEM, 555, Total Chaos, etc have the indexing sleeves. Even the one's I've seen from AutoZone have indexing sleeves on the outer 2 bolts.

There's enough meat on the LBJ. The holes that have the sleeves in them are already halfway drilled to M12 (to allow the sleeves to be pressed in. There is more meat around the inner two than the outer two. The only issue I see that may need to be addressed is the two inner holes on the spindle it's self may need to be built up to provide more structure around the bolt holes.

The sleeves on the LBJ, where the bolts failed on mine, are worked over. They were damaged with everything flopping around.

 

Is the assumption that these aren’t failing from side loads necessarily, but from essentially being pulled apart at the bolts?

 

The loads that are put on those bolts are both side to side, shear, as well as pulling apart.

THAT is why this LBJ design is so dumb.


The hub is on the spindle, meaning the weight of the truck is essentially making the tire push the spindle UP. While the coilover is pushing the LCA DOWN.

The tire, attached to the spindle, tracking is keeping the spindle straight, while the input in steering, attached to the LBJ, is twisting the LBJ against the spindle staying straight.

 

Yeah they’re getting screwed all the way around for sure, just wondering if the most detrimental thing to the bolts is them getting pulled apart in tension. Would be curious to hear from other bolt failures to see if the indexing sleeves were getting sheared off as well. Would think that would happen if the bolts were getting sheared that way, too.