How to install/torque knuckle and drive flange studs (1 Viewer)

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Aug 1, 2017
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Seattle, WA
Did a passenger side knuckle rebuild on by 93 cruiser yesterday. As I was taking the bolts off the knuckle studs, one of the studs came out completely when I tried to take off the bolt and I could tell that two of the others were loose. I gave them all a good tighten with some vise grips but my question is what is the proper way to install and torque these studs? Was thinking I would try the Lisle stud installer but it seems like it might be too fat...

Also seems like the drive flange studs need the same thing. As I was putting that cone washer/bolt assembly back together three of the bolts got on the studs and then got to a point where they just spin and spin without tightening. I was really careful to seat them properly and I feel like there is no way I cross-threaded three bolts but what else might cause this? I saw some stuff about maybe causing an issue by hitting the studs to knock the cone washers loose, which is what I did to get them off....I had to hit the brass hammer pretty hard...

Anyways I tried to loosen them and hit some resistance. When I kept loosening I noticed the entire stud was loosening, not just the bolt. So I'm thinking I need new studs there as well, or at least to torque them properly. Anyone have a good method for this? And why are these studs such a pain anyways? I really don't want to lose steering like some other folks have...
 
Joined
Jan 9, 2004
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1,609
Did a passenger side knuckle rebuild on by 93 cruiser yesterday. As I was taking the bolts off the knuckle studs, one of the studs came out completely when I tried to take off the bolt and I could tell that two of the others were loose. I gave them all a good tighten with some vise grips but my question is what is the proper way to install and torque these studs? Was thinking I would try the Lisle stud installer but it seems like it might be too fat...

Also seems like the drive flange studs need the same thing. As I was putting that cone washer/bolt assembly back together three of the bolts got on the studs and then got to a point where they just spin and spin without tightening. I was really careful to seat them properly and I feel like there is no way I cross-threaded three bolts but what else might cause this? I saw some stuff about maybe causing an issue by hitting the studs to knock the cone washers loose, which is what I did to get them off....I had to hit the brass hammer pretty hard...

Anyways I tried to loosen them and hit some resistance. When I kept loosening I noticed the entire stud was loosening, not just the bolt. So I'm thinking I need new studs there as well, or at least to torque them properly. Anyone have a good method for this? And why are these studs such a pain anyways? I really don't want to lose steering like some other folks have...
If you are trying to tighten them and there is no resistance then you have most likely stripped out the holes or the threads on the studs. Pretty easy to diagnose when you remove them again. If they are stripped out I would recommend tapping etc holes to 7/16" fine thread and use hex drive cap screws. The hubs are actually quite soft and very easy to strip out. I usually drill the existing holes a bit deeper with a 3/8" drill and follow tapping the holes with a regular tap with a bottoming tap. IIRC I use 1.5" long 7/16" fine bolts. Much stronger and no need to add all the extra dowel pins that some sell in their kits. The hardest part is drilling the drive flanges. I use loctite to keep them seated as they will have a tendency to loosen without the tapered cones.
 
Joined
Dec 10, 2007
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7,514
AFAIK there's no torque spec for the knuckle studs, I tighten until the unthreaded portion bottoms out.

FWIW there's a newer High Strength thread locker that doesn't require heat
to remove the fastener, supposed to hold 3X stronger than Blue thread locker. No experience with taking anything apart with it yet however.


If you decide on getting a good used replacement knuckle and hub there
are a couple of vendors/members who part out vehicles reqularly. Check
the parting out section in the Classifieds.
 
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SNLC

OCD
Supporting Vendor
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Boise - Idaho
FYI, new knuckles are available at a good price if you stripped out the stud holes.

Also take a close look at threaded holes for caliper mounting. These stripping out is not super uncommon.

I recommend a new knuckle if you have any issues, the knuckle is a critical part and if taken care of will last the life of the Cruiser. If just installing caliper bolts with the impact, we’ll ya. 🤷🏼‍♂️

Cheers
 
Joined
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Seattle, WA
Thanks for the tips. I'm gonna go ahead and try and torque the knuckle studs this weekend. Just to clarify, its the bolts on the drive flange studs, not the knuckle studs, that spin and spin without tightening. I don't have any reason to suspect that the knuckle threads are stripped but I might need a few new studs for the drive flange.

Regarding the two bolt thing, anybody know what size bolt goes on the knuckle end of the studs? Seems like the threads on the knuckle stud are spaced differently at the different ends. I was thinking I would just use one of the bolts that came off one of the other studs to do it but it doesn't quite fit right on the other end of the stud.

Also I was cleaning up my tools and stuff yesterday afternoon and I realized I may have missed something. I found this little ring on the ground, about the size of a half dollar. I don't remember taking this off specifically. Does anybody know what this is?
19F7F657-9481-41F0-B08C-FCFE03CBCF31.jpeg
 

ppc

M Go Blue
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Nashville, TN
That is called a garter spring that is part of a seal to retain it's form. If you recently did a frontend service that spring is from the inner axle seal. Could be from the old seal or the new one. They come dislodged when the axle is removed or installed. To minimize this happening with a new seal you should place grease around the spring to make it less likely to come off.
 
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Seattle, WA
Thank you @ppc ! It's from the old one. I remember it popping off when I was trying to pull the old seal out but I thought I was careful to throw it in the trash pile. Must have left it laying around! Anyways that makes me feel better. So studs are all I have to worry about...
 
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Charlotte, NC & Alexandria, VA
From your original post, it's hard for me to picture exactly where your problem(s) is(are). I'm assuming that the "bolts" you're referring to are nuts, since a stud is a bolt without a head. For clarity, here are the parts diagrams for the area in question:

Parts, steering knuckle, pg SA-13 (RM432U).png


Parts, front axle hub, pg SA-8 (RM432U).png
 
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Working from the inside out,
there are (8) bolts that fasten the knuckle spindle onto the steering knuckle, sandwiching the gaskets and dust shields between the two. These bolts face inwards, toward the centerline of the truck. According the the FSM, the torque spec for these is 34 ft·lbs;
there are (6) bolts, fastening the disc to the hub (not the (6) road wheel studs, which are pressed into the hub; these studs face outwards, away from the centerline of the truck). These bolts face inwards, toward the centerline of the truck. According the the FSM, the torque spec for these is 47 ft·lbs;
finally, there are (6) studs in the hub which fasten the drive flange onto the hub, sandwiching the flat and cone washers between them, using a nut. These studs face outwards, away from the centerline of the truck. According the the FSM, the torque spec for the nuts on these studs is 26 ft·lbs. There is no torque spec for the studs into the hub; you turn them until they bottom out, securing them with thread locker. Unless you have a stud driver, you must use two nuts, tightened against each other, to do this.

If the drive flange/hub studs spin when you tighten the nuts, either doubly or singly, you have three options. (1) replace the hub. (2) repair the thread using a Helicoil, or similar insert repair part. (3) drill and tap for a larger thread. IMHO, the list is in order of best practices. If you choose (3), make sure you use a SAE Grade 8, or better or Metric Class 10.9 or better bolt or stud, whichever you prefer. Anything less will fail.

FWIW, it's completely acceptable to replace the drive flange studs with bolts (technically cap screws, since they are threaded into a part, and don't use a nut). The studs are a legacy design concept, intended to reduce the number of loose parts lying around during maintenance and to reduce the frequency of internal thread failures, due to removing and reinstalling screws into tapped holes. You have to keep in mind that the first Land Cruisers were copies of US Army trucks which were all over Japan at the time, left over from WWII. The Japanese were smart enough to realize they didn't have the experience designing a wide range of heavy, off-road vehicles and copied what worked from what they saw around them.

HTH
 
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