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404 Steering Knuckle coming apart

16K views 51 replies 19 participants last post by  tjmark 
#1 ·
I have a couple questions. I have a custom 404 / Toyota axle in my crawler and I am having a problem where the steering knuckle joints are backing out. So essentially the axle shaft pushes heavily on the axle tube seal causing it to leak and my CV joint starts to rub on the inside of the knuckle.

1) How can I prevent this from happening? Is there something wrong with my ball joints that I should replace them? The passenger side doesn't have this problem, so I am wondering if it is a wear item or just a common maintenance things.

2) What tool(s) should I use to push it back together. In this picture below it is backed out by about a 1/4 of an inch.

Thanks for the help.
-Sam

 
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#36 ·
As much as you'd think it would 'press down' upon the rigs weight and 'settling', they don't seem to work that way:(
In your pic, the left one seems right, fully pressed down.
The one on the right 'looks' good where the hardened pin sticks thru (depth), but that the bearing cage is loose is bad. It needs pressed down some more. (IMO)
Look for a pin that may be holding it in place, I have heard of some being (roll) pinned to keep that bushing/king pin in location. If that is true, I don't know what to tell you.
 
#37 ·
Makes sense I guess, but to through one more data point in the pot. The other side of the 7 year abused kingpins is tight, but has approx half the clearance of my old loose one and the new one. So at least that much clearance seems OK (theoretically). Clear as mud.........
 
#38 ·
Maybe my outlook on this is too simple but if there isn't a clearance issue during reassembly then it shouldn't matter, that bearing does not take stress in that direction. But I don't really know. If it was mine I would assemble it and take it around the block, maybe wiggle the steering a bit see if it feels sloppy.
 
#40 · (Edited)







Not sure if these will help, had these on my computer when Mo pedal was selling/explaining how he had a machine shop to some work and put bigger pins in. It also looks like some welding was done on the top of the knuckle to strengthin it after the larger pins were installed? Anyhow might give you guys some ideas on OD demensions for what size pins to fit. I have a set of 404's also so this is in the back of my mind too.
 
#41 ·
On a stock Mog with 20" wheels and drum brakes the center of the tire (thus the load applied) is very close to the steering axis. This means there is very little leverage on the kingpins, so when your pounding down a rock trail the shock goes vertically up thru the kingpin. I think when you go to disc brakes and offset the wheels outward your adding a lot of leverage to the kingpins they weren't designed to handle. I think this is why they get loose in the first place. I'm using the stock drums with Hummer wheels backspaced to the absolute max and I haven't had these kind of troubles (yet anyway). The wheels are so close to the drums I've had to seal off the outside of the wheels so mud and rocks don't collect in the wheels (keeps them a little lighter too).
 
#43 · (Edited)
I know there are many opnions on the fix. I have had really good results from the new bolt we made. It is not a mass produced bolt. We only made 2 sets. Since it truly captures the lower kingpin it can no longer slidehammer itself and wobble loose or wollow out the kingpin resulting in broken kingpins. I suspect the only reason the kingpins break is from not seating tight and creating leverage when they back out. Then they break the pins.

Mark
 

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#49 ·
they do require you to turn the kingpin down and machine the knuckle flat so the bolt head sits flat..

I'll see what it will take to make a few more..
 
#51 ·
I have both a lathe and a mill.
I guess if I am going to be machining the knuckle anyway I could just make myself a couple if you don’t want to.
What part of the king pin needs turned?
I see it has an Allen head, did you turn down an off the shelf bolt?
 
#52 ·
It is a 4340 heat treated bolt. One off from solid stock...
 
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