Knuckle Arm bolt missing..... (2 Viewers)

[Wayne]

While under my truck, I noticed the right hand knuckle arm was missing a bolt and two of the remaining three nuts were loose . I've replaced the missing bolt (used Locktite) and attaching hardware, and now have all four nuts torqued correctly . Those nuts are torqued to more than 70 lb-ft...... so, what do you think caused them to loosen up and the bolts to back completely out? Anyone else every hear of this or experience it first hand? The ones on the left side were torqued properly.

Wayne S

 

[semlin]

Do you mean the studs? The studs will sometimes come loose during a knuckle repack. PResumably that is because you have to pound on the stud heads to loosen the cone washers.

 

[bjowett]

These 4 studs get sheered off once in a while by the hardcore mini truck guys with big tires on big rocks.... probably a torque issue... I frequently checked the torque on the 4-Runner, and will definetly do so on the Landcruiser. Since one was missing, and two were loose, I would recomend replacing the remaining 3, there is a good chance they were weakened considerably from the steering arm twisting on them.

 

[cruiserdan]

The studs were most likely loosened in a previous knuckle job. The nuts were probably tight when the previous job was completed, but with studs not fully seated. I have seen this more than once and in every case it was at some time after a knuckle job (birf job). The worst one was a case from our own shop. The vehicle was re-assembled and everything was tight. A few weeks later the vehicle came in "on the hook" missing the right front wheel The studs had backed out and the knuckle came apart ON THE FREEWAY. Luckily no injuries and the driver kept her head and didn't lose control. It was a VERY EXPENSIVE come-back but could have been a helluva lot worse.

IT IS IMPERATIVE THAT THE STUDS BE CHECKED BEFORE RE-ASSEMBLY OF THE KNUCKLES. IF THEY ARE LOOSE, REMOVE THEM, CLEAN AND DE-GREASE THE STUDS AND HOLES AND RE-ASSEMBLE WITH LOCKTITE.....


D-

 

[Wayne]

Yes, the studs are listed as "lobular bolts" on the parts list. New ones have a #12 torx tip on the external end that requires an external torx socket to install it in the knuckle. I didn't think about replacing the other three, but I will give that some thought.

Wayne S

 

[Cruiserdrew]

Yes and you'll be glad to know that Toyota is very proud of these particular studs-I bought a set for my FJ60 (I think they are the same) $8 each!!! I have heard not to locktite them-when they do break, then it will be impossible to get the remainder out of the hole. I just seated them very firmly-the Toyota manual does not give a torque spec for the studs, just the nut. I used 50 foot pounds for the studs and 71 for the nuts. I think Marlin might sell them cheaper, but I would buy the real thing from Toyota. This is a mission critical bit-buy the best. I'll bet C-Dan could hook you up. I also agree with the post about replacing all 4. I have seen them broken with some regularity on the Rubicon. Pismo Jim got me checking the torque on these nuts after every run. I think it's good practice.

 

[Wayne]

What do you guys think about using a nylon insert self-locking nut on these studs :-\? They don't even have lock washers under them stock ???. With the potential for a major disaster if the knuckle arm comes loose, some type of lock washer or nut seems like a must . "This is definitely a safety of flight discrepancy."

Wayne S

 

[landtank]

Wayne I'd skip the nylon style nut and go straight to the jamb nuts. These are all metal with a slightly deformed side that jambs onto the stud. They are common in high vibration applications.

 

[cruiserdan]

I respectfully disagree with the use of jamb nuts or nylock nuts.

If fasteners of these types were deemed required, they would be there from the start. Toyota, as a rule, is very conservative. I believe that fasteners of that type would be there if Toyota thought they should be. The issue, as I see it, is studs that have been loosened. ANY nut torqued against a loose stud does not stand a chance..........


D-

 

[landtank]

Dan, what about these new style studs that have been mentioned? Do you have any more info on them? As far as locktite on the studs. I've used heat to break the bond on our applications. Not sure what grade of locktite we use.

 

[cruiserdan]

The lower knuckle studs have been superceded from 90116-12007 to 90126-12005. the new style stud has a #12 inverted Torx end to make it easier to install. That is really the only difference that I see between the two. The new style studs list for $1.57 each. I do not know where the 8 dollar figure cited by Drew came from unless his dealer was short of cash :-\
These studs are also used top and bottom on 79-up 40,45,55,60,62 and solid axle mini. 12-78 and back knuckles have 11mm studs.

D-

 

[landtank]

Thanks Dan. I'll have to keep those in mind for the next rebuild.

 

[Cruiserdrew]

>The new style studs list for $1.57 each. I do not know where >the 8 dollar figure cited by Drew came from unless his dealer was >short of cash

Ouch I even asked the parts guys at the dealer to check if that was right, then I pissed and moaned somemore and we got down to $5 something. It's funny, I have even defended those guys, and they have gone out of their way to help out a couple of times, but if I got screwed out of $4 per stud, I'm pissed and that's the last $ they will see of mine. I guess Mr. Maita had a boat payment due! Live and learn, thanks for the lesson Dan. It looks like I'll be buying my parts in New Mexico!

 

[erics_bruisers]

I just found 32 of these in my parts box -- the 90126-12005s -- they will get used this weekend on my 91, lest they sit around another 60K miles -- that ain't gonna happen --

e