Front axle king pin holes

2

28 fast faton

Member
Hi guys. I had some play in my front wheel so I disassembled the spindles thinking I need new bushings but it looks like the axle hole has worn and is oversized. I read where someone put the kingpin in the hole and run an arc weld vertically down the outside of the hole so it would shrink when cool. Has anyone ever tried this and if it’s possible can I use oxyacetalyn. I also thought about putting JB weld in the hole, surround wax paper around it and install the king pin. Once hard pull the pin and paper and good to go ( I was hoping).
Any thoughts
 
J Franklin said:
There is a wedge bolt that locks the pin in the axle when tightened.
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If the nut on that cotter pin (yes, that IS a cotter pin) is overtightened, the hole can be stretched. Henry used only the BARE minimum of metal so the ends of the axle are not very strong and prone to such damage.
I've heard of using the arc welder to fix it but haven't any experience to pass on in that regard. I recently had 2 axles where the holes were stretched and I took them to a guy who repairs and straightens them. I don't know what he does to shrink the holes but what ever it is, it WORKS.
I'm sure there will be someone over there who can rectify this for you, it's just a matter of finding him.
Filling the gap with epoxy (JB weld) or shims is not good enough. There is not enough metal around the eye to allow boring for a sleeve. The only way is to shrink the eye and have it reemed if necessary.
There is a lot at stake if the axle fails so DO IT RIGHT!
 
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Maybe you need a machine shop or look for an other axle, there are a lot out there. Maybe some shim stock would tighten things up.
 
There is only one way to fix it right and that is to sleeve it.

A word of caution, find a machine shop that has done them before.

Depending on where you are, large truck repair shops do this all the time.
 
Another fix that might work but depends on the amount of clearance that exists between the king pin and the axle bore. If the clearance is within a few thousands (.003" -.010") you could have a new pin chrome plated .001" less than the existing bore. The chrome will have a hardness that is greater than the axle hardness. This is a method used to fix worn or out-of-spec aerospace components.
 
Chrome plating may be more expensive than sleeving the axle bores and it's only effective for clearances that are a few thousandths. Bores tend to get egg shaped on the ends of the axle and need to be trued back up for correct caster/camber. Folks that drop axles usually have to do this due to stretching of the bores during the dropping process depending on what procedure they use.
 
Not much in the way of options. Finding a machine shop that will do the job right at a reasonable price may be just as challenging as finding a serviceable axle. Probably a two pronged approach forward might be considered. The axle has to be pulled either way. If a good axle could be located it would be the surer fix. Please share how you ultimately do the fix.
 
I walked into a local machine shop (one man shop) and he had a Model A axle propped up in the Bridgeport. Recognizing the axle, I got into a conversation with the machinist and he says he does this infrequently, but perfectly (his words.)

"Doesn't sleeving it reduce the material in the axle eye and weaken the axle?"

"Somewhat - but there is some excess for strength - I do have to remove a bit more than is necessary to actually do the sleeve, but I have to use a sleeve thick enough to press in and then machine in place. I've never had anyone come back with an axle failure."

So it is done - not frequently - but perfectly.

Joe K
 
Pete said:
There is only one way to fix it right and that is to sleeve it.

A word of caution, find a machine shop that has done them before.

Depending on where you are, large truck repair shops do this all the time.
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That works fine, so long as there is enough extra strength in the axle eye but not on Model A! Henry didn't leave enough steel for this to be done without weakening it too much. I looked into doing this and decided my (and my passengers and other road users') lives were too important. Imagine the liability issues you could face when it fails! NOT for me on a Model A!
 
Synchro909 said:
That works fine, so long as there is enough extra strength in the axle eye but not on Model A! Henry didn't leave enough steel for this to be done without weakening it too much. I looked into doing this and decided my (and my passengers and other road users') lives were too important. Imagine the liability issues you could face when it fails! NOT for me on a Model A!
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Just curious, how thick was the wall of the sleeve you intended to install?
 
Pete said:
Just curious, how thick was the wall of the sleeve you intended to install?
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The absolute minimum but we decided there wasn't enough "meat" to put in any sleeve safely. The metal around the middle of the eye is very thin - it's a testiment to the quality of the steel that they held together at all, IMO.
 
Synchro909 said:
The absolute minimum but we decided there wasn't enough "meat" to put in any sleeve safely. The metal around the middle of the eye is very thin - it's a testiment to the quality of the steel that they held together at all, IMO.
Click to expand...

Ok.
It seems a .040 wall sleeve worked fairly well in vintage sprint cars. Even after they hit the wall or rolled over several times. No breakage on the 100 or so I have done so far.

The steel was a proprietary Ford formula but was almost the same as SAE6150.
 
Thanks for all the info. Because I am avoiding removing the axle and have nothing to lose, I am trying an experiment. I put jb weld in the axle hole where it appeared to be worn on the top and bottom and wrapped the kingpin with one layer of wax paper and installed the king pin and locking nut ( not 100% tight) Today I removed the king pin and then removed the wax paper and reinstalled the king pin to check for play. It’s nice and tight like it should be after tightening the the locking pin. The question is how long will it last. Any thoughts?
 
King pin knuckle joints not only support the weight of the front end, they also take a lot of beating from bumps in the road at speeds that multiply the force somewhat. There are some pretty good shock loads even with the tires absorbing a lot of that. The front axle or control arms actually bend a little at road speed. This is why they generally always have a toe in setting when being aligned. Plastic bushings don't hold up well and with epoxy in there, that's essentially what you have created.
 
Thanks for that. You are most likely right. If I get the summer out of it I will be happy. I am hopeful though because a bushing is designed as a sleeve for a moving part and this is a stationary part. Maybe some movement as you said due to flexing etc but mostly pressure. I’ll keep you posted.
 
If you must go down the road of using a filler around the king pins, I'd use Loctite No 243 but you'd need heat to take it apart. 243 is the one for taking up slack in keyways and splines etc.
 
Why not use shim stock instead of plastic or other chemical filler? Especially with a locking cotter. Just curious.
 
I did think about shims but it would most likely be aluminum and when jb weld advertises stronger than steel I decided to make my shim from jb weld instead. It has 3900 psi of strength so it’s a test to see what it will hold up to.
 
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