Why do our LBJs fail?

[Kryptoroxx]

I just replaced mine and while they were leaking the joint still had life in it. I tossed them in the spare box.

Wouldn't it be better to modify the arms so they could use a heim, Johnny or creeper joint? I've seen someone do uniball arms but I'm afraid back east those would not last at all.

I'm just getting started in fabbing my own parts and I'm not foolish enough to make a go at upper and lower arms but there has to be a better design out there.

 

[Nelsonmd]

NelsonMD - I was actually going to suggest the OP do a search for the past LBJ articles where you have commented in detail on this subject.

Yeah, there was one where a couple of us posted some pictures and diagrams of the 3rd vs 4th gen designs. I wish that was in the master thread or something so we could save ourselves some of these reposts. That was actually a pretty good discussion for being on the internet...

Balljoints used in tension have been used in a LOT of applications. Pretty much every Chevy 1998 and down truck chassis was this way. Toyotas, nissans, and even mazdas were all used with tension applied to the lower balljoint. So it's not something unique to the 4runners like this forum makes it seem.

However I will say that a lower balljoint is far superior as a compression vs tension design since it always has the weight of the vehicle keeping it together.

Yeah, I have mostly seen tension ball joints on cars though, not trucks. I certainly don't know for sure, but I'd guess that tension is ok for a low suspension preload application and low load carrying application, but probably not OK for a truck. Trucks need to be designed differently.

The way you guys talk about these, makes it seem like they total crap. Mine are original with 178k on them, no play, no grease leakage. I can understand needing to replace them more often if you go off road, have bigger wheels/tires, suspension lifts, etc. But for a ball joint to last over 100k is not too shabby in my book.

They aren't total crap for sure. The problem is that normal wear items that are so safety critical need to be held to a higher level of design than "just acceptable". Also, knowing that this part will be serviced by the aftermarket, and serviced by lots of weekend mechanics, and dealers/mechanics that don't give a crap about specs, Toyota needs to design these parts to be more robust. You can't rely on a fancy high strength alloy that no one else will use, or that requires special treatment. And you can't have a design that fails before it gives clear symptoms of failure at the regularly scheduled intervals. They know not everyone, even dealers, will be a vigilant as they spec.

Remember, US law says that if Toyota REQUIRES that a Toyota brand part be used to replace a normal wear item, then Toyota is required to provide that part for free to all vehicle owners for the life of the vehicle.

As far as I know mine are original and if in fact they are they have 300,000 miles on them. I have read about a lot of failures on here recently. The other day I ordered a set to replace mine in an effort to prevent ever having to deal with a dangerous situation due to failure.

I believe it was a poor design.

300k on an original wear item is not frugal, it's asinine. I highly doubt they are original anyway. They may be OEM, but not original. This is a 90k life item. IIRC, the manual says to replace them at 90k even if they dont' have any play.

I have had two of these runners with over 220k on original ball joints and are fine

Yeah, there is always anecdotal evidence saying anything. I'm sure ther's people out there that have had them fail before 90k too.

Examples like this indicate that the issue is probably in the manufacturing process, rather than the original design. I've worked in production metal casting, and it's tricky business. There's probably something happening during the process that causes some parts to be weaker than others, but is hard to detect.

But having said that, engineering parts so that it's possible to produce them with high quality is a huge part of the challenge of maintaining the reputation that Toyota has.

I don't know if it is a manufacturing defect or if it's just a lower safety factor than it should have been. If they quote a 90k life, then the failure life should be 2-3x that. I don't think the anecdotal evidence really suggests a manufacturing defect as opposed to design weakness.

 

[krenaud33]

300k on an original wear item is not frugal, it's asinine. I highly doubt they are original anyway. They may be OEM, but not original. This is a 90k life item. IIRC, the manual says to replace them at 90k even if they dont' have any play.

I bought mine with 165,000 on it and it just turned 300k. They haven't been replaced yet. I guess I have been fortunate to not have issues.

 

[D Farms]

i had mine replaced by toyota at 60k and now i have about 250k. i check mine pretty much every time before i wheel, and i havent seen any grease leakage. I think they can fail if a lot of salt or other shitty chemicals get under the rubber. I personally do not think lifting makes a difference since the boot is not being stressed, however wheeling it all the time will definitely put more stress on it than normal and can cause the joint to loose grease and then fail.

 

[Nelsonmd]

I bought mine with 165,000 on it and it just turned 300k. They haven't been replaced yet. I guess I have been fortunate to not have issues.

Well then, I am glad that you are replacing them now. Very smart move.

i had mine replaced by toyota at 60k and now i have about 250k. i check mine pretty much every time before i wheel, and i havent seen any grease leakage. I think they can fail if a lot of salt or other shitty chemicals get under the rubber. I personally do not think lifting makes a difference since the boot is not being stressed, however wheeling it all the time will definitely put more stress on it than normal and can cause the joint to loose grease and then fail.

190k and with wheeling? I'd replace them even if they feel tight as a drum. Even if you don't have looseness, the materials get old, may have some corrosion, may have some micro-cracks, chemically induced hardening, loss of tempering, general fatigue, etc. and could still fail without warning. IIRC there has been 1 or 2 LBJ failures where they failed at the stem of the ball, not with the ball pulling out of the cup. Stem failure will not show up as looseness when you check.

I am not sure exactly what component bottoms out first and second when articulating, but it is possible that while wheeling, you could bottom out the LBJ a bit, which would really be a bad situation for creating microcracks in the stem by putting a bending force on it. I think the UBJ bottoms out first, but it has no preload, so I think it can probably take some beating without failing outright.

I seriously recommend replacing them soon. You can keep the old ones as backups if you want, but I wouldn't want to drive much on them after that long a life. That's like having your grandpa take a kickoff return in an NFL game. He may be able to call some fair catches, but if he gets hit, man, that could be it...

 

[jkoni426]

...maybe its the lifts killing them.

I'm convinced this is the main reason they fail prematurely. Lifting throws off the geometry putting more stress on the lbj at an angle they weren't meant for. That's why so many fail soon after lifting.

 

[jeremyc74]

I don't know if it is a manufacturing defect or if it's just a lower safety factor than it should have been. If they quote a 90k life, then the failure life should be 2-3x that. I don't think the anecdotal evidence really suggests a manufacturing defect as opposed to design weakness.

When you have some parts failing after 90k miles, and others that last 200k, that's the first sign of a manufacturing irregularity. Trust me. I do this for a living. You'd be shocked at all the strange things we see in manufacturing processes that cause failures over the long haul.

Now, it could be that the original spec isn't tight enough and that allows the weaker parts to be considered good, but the failure rate shouldn't be that erratic.

 

[Nelsonmd]

When you have some parts failing after 90k miles, and others that last 200k, that's the first sign of a manufacturing irregularity. Trust me. I do this for a living. You'd be shocked at all the strange things we see in manufacturing processes that cause failures over the long haul.

Now, it could be that the original spec isn't tight enough and that allows the weaker parts to be considered good, but the failure rate shouldn't be that erratic.

Oh, I understand. I'm an automotive engineer, I do it for a living too. I have audited many different manufacturing sites, from making tiny capacitors, up to automotive sub-assemblies, and I have done tons of FA for both manufacturing defects, and oodles of field returns. Actually I am writing during in some down time during a spec review with one of the asian OEM's...

When you have a part that is designed to have a life of 90k, the design, material selection, and process specs are written to achieve a 90k life with a certain safety factor. Most of the time, the actual life span is the max that can be achieved at a certain price point, so it could be adjusted up or down pretty straightforwardly by either cheaping out, or investing in better materials/process. For non-wear items, the failure life is typically in the range of 2-3x the operating life spec'd out (because nothing lives forever). For wear items it has to be different, you can't maintain a 2-3x failure life on an item that is expected to wear out. That doesn't mean they are guaranteed to fail after their lifetime, I mean some little old ladies have gotten 100k+ miles out of their brake pads by never braking hard, despite the pad life only being something like 30k or less. You'll always have some cases that don't see harsh conditions and last forever, and you'll always have some individuals that just seem to last forever, even in harsh conditions. The dimensions all line up in their respective tolerance stacks to make those parts just perfect. Then you have others that don't have anything out of spec, but fail early, because statistics... or because the tolerance stack wasn't perfect (they're harder than you think...).

Even with perfect manufacturing, you will have significant variation in lifespan of things like this because you have imperfect life conditions and imperfect materials. Anecdotal variance between 90k and 200k doesn't surprise me at all. For that matter, I don't recall any that broke right near 90k either. Most don't know how many miles, but the few that did I seem to remember them breaking in the 100k's.

It would be interesting if someone sifted through all the threads and made a list of all the failure mileages.

 

[scrapper]

Oh, I understand. I'm an automotive engineer, I do it for a living too. I have audited many different manufacturing sites, from making tiny capacitors, up to automotive sub-assemblies, and I have done tons of FA for both manufacturing defects, and oodles of field returns. Actually I am writing during in some down time during a spec review with one of the asian OEM's...

When you have a part that is designed to have a life of 90k, the design, material selection, and process specs are written to achieve a 90k life with a certain safety factor. Most of the time, the actual life span is the max that can be achieved at a certain price point, so it could be adjusted up or down pretty straightforwardly by either cheaping out, or investing in better materials/process. For non-wear items, the failure life is typically in the range of 2-3x the operating life spec'd out (because nothing lives forever). For wear items it has to be different, you can't maintain a 2-3x failure life on an item that is expected to wear out. That doesn't mean they are guaranteed to fail after their lifetime, I mean some little old ladies have gotten 100k+ miles out of their brake pads by never braking hard, despite the pad life only being something like 30k or less. You'll always have some cases that don't see harsh conditions and last forever, and you'll always have some individuals that just seem to last forever, even in harsh conditions. The dimensions all line up in their respective tolerance stacks to make those parts just perfect. Then you have others that don't have anything out of spec, but fail early, because statistics... or because the tolerance stack wasn't perfect (they're harder than you think...).

Even with perfect manufacturing, you will have significant variation in lifespan of things like this because you have imperfect life conditions and imperfect materials. Anecdotal variance between 90k and 200k doesn't surprise me at all. For that matter, I don't recall any that broke right near 90k either. Most don't know how many miles, but the few that did I seem to remember them breaking in the 100k's.

It would be interesting if someone sifted through all the threads and made a list of all the failure mileages.

This makes sense. I bought my 2002 new. I used it as my daily
driver seeing clients and going to meetings all over the tri state area
not modifying a single, suspension, wheel/tire, etc. thing until just
recently. I am at 207k with no failure or even replacement of LBJ.
I'll replace them now along with my timing belt based solely on
mileage alone.