What year is your FJ?
How many miles on it?
Any modifications done to the drivetrain, other than the recent half shaft replacement?

 

Thank you for reply. It's a 2008, 183k mi, I installed Bilstein 5100s on the neutral position using the existing springs which are 2 and 1/2-in lift.

 

Kerchow!

 

who replaced the Axle?

 

Is your FJ lifted? How much? Did the ball pop out of the socket or did the stud break? Stock UCA by the looks if it, they don't like lift + high miles.

 

The Steering Knuckle has to be removed to replace the Front Axle ... which involves disconnecting the Steering Knuckle from the Ball Joint on the Upper Control Arm.

Assuming a competent shop ... if the Upper Ball Joint was compromised ... due to age / mileage (or whatever) ... the mechanic should have flagged as an issue and addressed.

Can you tell if the Ball / Socket separated ?

Watch this video ... at 10:42 minutes the Upper Ball Joint is separated from the Steering Knuckle ...

 

The Steering Knuckle has to be removed to replace the Front Axle ... which involves disconnecting the Steering Knuckle from the Ball Joint on the Upper Control Arm. (snip)

Actually only the lower ball joint needs to be disconnected, and the spindle can then be swung out to allow the outer end of the CV to be disengaged from the spindle.

I suppose it would have been possible to overstress the upper ball joint during this process, especially if the joint was already badly worn.

I suspect that the ball pulled out of a badly worn socket, rather than the tapered stud broke.

OP, exactly how did the upper ball joint fail?

 

 

By the looks of it they removed the lower ball joint. There are marks from the impact socket on the bolt for the lower knuckle bracket. It is easier to unbolt that and pull the knuckle away and less likely to do any damage to the brakes lines. Chances are it's just a coincidence. If there was enough wear and tear on the axle to need replacement then the joint could have been ready to fail.

 

Within a 3-day time-frame ... Coincidence ? ... plus the mechanic should have flagged the upper ball joint if the wear was that close (3-days) to the point of failure ... and happened on non-off-road conditions.

 

Can anyone offer an explanation for Toyota's recommendation to orient the gap in the CV axle's retaining ring at the 6:00 position during axle installation?

(From the FSM attached to post #2)

 

Can anyone offer an explanation for Toyota's recommendation to orient the gap in the CV axle's retaining ring at the 6:00 position during axle installation?

View attachment 1219881

(From the FSM attached to post #2)

The only reason I can think of is less chance for the ring to catch the front differential bore when being inserted. Especially due to gravity the ring will tend to settle down, with the gap on the bottom there will be less ring exposed. I've always tried to do it this way.

 

A photo from the rear side of the tire, which captures the ball joint on the UCA is what would be helpful.

You definitely don't need to disconnect the steering knuckle from the ball joint on the UCA to change the CV axels. If fact, disconnecting it would make the job much more difficult, since you'd have the full weight of the wheel bearing to deal with. This is the setup I used when rebooting my CV axels earlier in the year:

Without being able to actually see the ball joint on the UCA, OP, all we can really do is just speculate.

 

A photo from the rear side of the tire, which captures the ball joint on the UCA is what would be helpful.

You definitely don't need to disconnect the steering knuckle from the ball joint on the UCA to change the CV axels. If fact, disconnecting it would make the job much more difficult, since you'd have the full weight of the wheel bearing to deal with. This is the setup I used when rebooting my CV axels earlier in the year:

View attachment 1219892

Without being able to actually see the ball joint on the UCA, OP, all we can really do is just speculate.

You have beefier UCA's / Ball Joints ... with probably less wear-and-tear ... and have the steering knuckle weight properly supported with a jackstand. Midas may not have approached with the same "Touch" (no advertising pun intended).

 

Good last question. Friend recently did the same with his 2005 4-Runner ... Midas for Shock and Front Axle Replacement ... result was they swapped the (stock) front springs so the dreaded drivers side lean was even worse, and also sheared off the ABS Sensor which they refused to address. They did swap the front springs back to the proper sides but not without first arguing as to why it was necessary.

 

Exactly. I wanted to give him a point of reference for how things should be done.

 

Stock UCA with a lift on 180K mile truck is what happened. Tinkering with it could have just pushed it over the edge. I am sure they were not the most gentle, and they would have had to beat on the spindle some to release the tie rod end from it at the very least.

 

Agree ... but still no excuse for ANY shop to not flag a compromised Ball Joint ... within 3-days of road-use failure ... no excuse ... total incompetence no matter the circumstance.

 

The automotive repair space is not regulated. Mechanics that are so motivated ... meaning dedicated professionals ... are ASE Certified ... not an industry requirement, but does indicate a level of expertise and professionalism.



Just because a shop has a National or Corporate name does not change the fact that ANYONE can go out and buy tools and say "I'm a Mechanic" ... so unless the (specific) shop manager is competent themselves ... and has integrity ... the specific "mechanic" working on ones vehicle could be an absolute hack or simply have no clue as to some of the make / model nuances relative to a specific repair. No guarantee ... and this even applies to some Dealerships.



Personally I would NEVER take my vehicle to a "Midas" or "Firestone" or any other Generic (we do everything) shop. A Dealership is probably the best in terms of expertise ... but has the highest labor rate. The second best option is an established independent shop that specializes in Toyota / Lexus. The third best option is an established independent shop that specializes in Japanese vehicles. None of these are a guarantee of competence ... so best to do BBB research and check on-line reviews. Also any law suits brought against a shop is available via public record.



Just because a "mechanic" is nice does not mean they know WTF they are doing specific to your vehicle ... or specific to the repair in question.

 

As an FJ and 4Runner owner, I'm interested in the types of failures that FJs and 4Runners experience. My day job includes failure analysis work, so I have an obsessive interest in exactly how and why things fail.

If along the way I see some 'information' presented in some Forum thread that is questionable, or obviously wrong, I point it out.

The hypothesis that 'clocking' the gap in the CV axle's retaining circlip somehow affects the force required to compress the circlip and get it to enter the side gear might initially seem to make sense, but a more thorough analysis of the mechanics and forces involved would seem to debunk that hypothesis.

You will agree that as the circlip first makes contact with the big conical chamfer on the side gear, any axial force pressing the clip against the chamfer MUST cause the clip to center itself on the chamfer? If simply visualizing this mentally isn't enough, it can be easily demonstrated using an arbor press or hydraulic H-frame press, a side gear, and a stepped piece of bar stock with a circlip positioned on it, simulating the stub shaft from a CV axle. Any CAD program that includes some kinematic capability would also confirm that the circlip self-centers as soon as it contacts the chamfer. Since the clip immediately self-centers on the chamfer BEFORE it even begins to compress, the initial 'clocking' position of the gap is completely irrelevant.

The questions I asked were primarily for the OP who had experienced the ball joint failure ... I was (and still am) interested in exactly how his joint failed, although I suspect that the joint was grossly worn out, had lots of internal clearance, and eventually the ball hammered itself out of the socket.

A few years ago a co-worker had a similar upper ball joint failure on a high-mileage but otherwise well maintained Tacoma that resulted in a loss of control in a location where leaving the road would have had very serious consequences, and his Taco finally stopped about 24" from leaving the road. Unfortunately, he was too shaken to take a close look at exactly how the joint failed, and we never got the full story on the exact point of failure.

My critique of the 'orient the gap' hypothesis isn't a personal attack, just sayin' that under closer scrutiny it doesn't seem to make sense.

 

Apologies first for continuing down a different trail from the OP's issue, but I cannot agree with all that you are saying. (I also do not typically open the forum unless the "Trending Posts" email prompts me to, so my responses are delayed.)

I would say your study of the mechanics and forces involved leaves out a few real-world factors. The first is related to the example of using a press with simulated components, which really is different in at least two ways. One is that the press is oriented at 90° to the direction in which a vehicle's axle would be, so gravity forces are perpendicular as well. The second difference with this example is that no technician I have ever seen uses steady, constant pressure to install an axle. Instead, we tend to use a quick, sharp, hammering force--sometimes even using the inner tripod joint as a sort of slide hammer. Both of those limit the ability of the circlip to self-center, IMO.

Another real-world difference is one that even Sir Isaac Newton could not get away from and that is the force known as friction. While the circlip may be rounded, the slot in which it fits has square sides and fairly sharp edges. This causes the circlip when forced sideway (because it will be) to hang up on those edges.

Again, the Toyota engineers who helped produce the factory service manual recommend facing the opening downward. My years in the field and a non-engineer understanding of the forces leads me to say: It does matter which way the opening in the circlip faces.

I also am still curious about the initial failure of this ball joint and wish we had some better pictures. There have been numerous failures of the lower load-carrying ball joint on Toyota trucks but less with the upper follower joint.

 

Actually I was questioning if anyone could provide a RATIONAL explanation of HOW orienting the open section of the snap ring could possibly have any affect on the ease of inserting the axle into the side gear. An cursory review of the parts and the dynamics of inserting the axle-with-snap-ring into the side gear didn't provide any insight into how snap ring orientation could affect anything.

I realize that the FSM suggests that the snap ring be oriented during axle installation ... my question is why.

 

The snap ring on a factory toyota axle is more of a C shape with the ends bent inward. With the opening at the bottom, only a small part of the ring, at the bend, is exposed around the 4 and 8 o'clock positions. More of a pinching action on the ring when installing or removing. With the opening at the top the entire width of the ring hangs below.
If that ring hangs slightly below the chamfered edge it could be problematic.
If the ring was a perfect circle, like on my aftermarket axle, it doesnt matter as much because you're compressing the whole ring. Was much more difficult to remove and install than the toyota axle. Changed my axle seals last weekend, this was my experience. I can't post pictures for some reason, hope this makes sense.

 

Yup, agree with everything you said, up to a point.

We agree that the snap ring is free-floating in its groove in the axle shaft, and only the 'ends' of the ring are 'exposed' (sticking out of the groove) at the 4 and 8 o'clock positions, correct?

Now we start pressing the end of the axle into the side gear, with the side gear's big conical chamfer at the mouth of the hole.

What happens to the snap-ring when those two projecting ends of the snap ring first contact the conical chamfer?

Does the snap ring move away from those initial points of contact, until some other part of the ring also contacts the chamfer, and only then does continued pressure forcing the axle into the side gear actually start to collapse the snap ring inward?

 

That is absolutely what happens. With the opening facing down, the initial points of contact are much smaller and less exposed, less likely to catch the edge of the chamfer. I would guess that is the reason toyota suggests it be done that way.