4500 Front Axle kingpin holes repair

UPFord

Member
I will redo this as a separate thread.

I'm prepping to do a rebuild on front axle of a 4500, previous owner included two complete kingpin and bushing kits.
The axle end kingpin holes are slightly egg shaped and allow the kingpins to move about 1/8", measured at upper end, when grabbing the wheel at top and bottom and rocking in and out. I'm planning to heat the axle ends and insert an old kingpin as a mandrel and hammer the axle ends smaller and rounder, and then knock out the old pin. When cool, ream/fit a new kingpin to the bore. then do the bushings.
Does anyone have experience with repairing worn kingpin holes on the 4400 or 4500?
Thanks.
 
The holes the bushings fit in are egg-shaped? In that case the kingpin will be a few sizes too small to make a nice thing to fit them to when heating and beating.

The bushings being worn eggshaped I'd believe. I'd also believe the holes they go in (or were supposed to be in, but they took a walk, or got worn all the way through) being worn egg-shaped - but in that case you need something the OD of the bushing to get that back to shape (or, as I keep dreaming, a portable line boring machine you or I can actually afford - build it up with weld & rebore it.)

Or this is the (supposedly non-moving) part of the kingpin mount that's worn?
 
I would install the bushing , and fill the egged out area with JB weld . It worked for me ....
 
The worn holes are in the ends of the axle, which holds the stationary part of the kingpin. the lock pin is tight, but I'm able to move the kingpin slightly toward the center of the tractor.

" Egg shaped" is a poor description, the upper end of the kingpin hole is elongated slightly toward the center of the tractor and the lower end of the hole is elongated slightly away from the tractor.

The bushing holes in the spindles are fine, just need bushings replaced.
 
If it were me I would bring it to a machine shop.
Have them bore and sleeve the egg shaped holes, weld the sleeves in then ream back to standard.
I wouldn't cost that much to have done - a couple of hours of shop time.
Using JB Weld in an application like that is a very bad idea. The weight of a loader would squeeze it right back out of there.
If I was dictator of all the world the first thing I would do is outlaw that damn stuff.
 
2 out of 3 respondents don't understand the problem. Sad... I, too would strongly consider bushing the axle and machining back to size right now as you have two new kingpins to supply for sizing.
 
OK, I'll jump in here on this one: I don't think your method will work very well. I don't think you could pound it enough to get enough surface contact area on the pin and get it to stay still.

Best solution, short of buying a new axle which I'm sure is not available or is obscenely expensive, would be to take it to a machine shop and have it bored oversize and then bushed back down to fit the standard sized kingpins. This would make the axle like new again.

If I were on a very tight budget and machining was not an option, I would rough up the bore and coat some JB weld inside the bore just before installing the pin. This might require removing the axle and rotating it 90 degrees so the JB weld on the bottom side doesn't run out.

While the JB weld option is admittedly "back woods", you don't have much to lose if it doesn't work. However, I think if you do it right, it would work. I've done some pretty amazing things with JB weld that has saved customers a ton of money. However, I always preface that option by telling them that it is not a 100% guaranteed repair.
 
I think it would work good in this case. The weight of the loader itself will not put any stress on the JB weld - the forces are in the wrong plane for that to be a concern. As long as the surfaces are properly prepped, and allowed to thoroughly dry, I think it will work. The other key here is to make sure the drawkeys are properly installed and checked for tightness after using it a few days.
 
Dunno Bern.
That pin is held captive in the bore and he says the lock pin was intact.
I'm thinking heavy loads in the loader stretched those bores, not wore them.
And you're saying JB - a plastic like material - would not squish out?
I'm more than a little sceptical.
A bore, sleeve, weld and ream job would last for many years and would not be the biggest expense a guy encountered when trying to rehab an old TLB.
Lastly, would I want to remove the axle again when the JB failed and I had to fix it right?
No.
 
I'm with Bern on this one. My preference would be to overbore the axle and sleeve it back to standard. I've done that several times on other applications axle related and it works well. Just make sure the bushings are welded in place. Now... if you need to do a homespun redneck repair to get you back in action because a machine shop is not available for whatever reason... then by all means, go with the JB weld. It will work, I assure you. My baler threw it's wrist pin on the plunger head last year baling straw.. and I had 2k bales laying in the swath that had to be baled post haste... on a long weekend. I filed and ground the rod with a dremel grinder to get he bushings fitted, cleaned it with ether and then put the JBWeld to it, fitted the pin for alignment between the two bushings, then packed the JB in with a rod... and let it sit about 12 hours. Reassembled it in the morning and went baling. Sadly it's still in that same condition... and still working. Probably done 4k bales since then.
As long as the JB has time to set up it will harden probably harder than the steel surrounding it. Under a compression type load it will be fine. Under a tension load it will break.

Rod
 
If the pins managed to stretch/deform the steel where there's no movement of the pin, I would not give JBW (or "plastic titanium", for that matter - best crap I could find at a whopping 18,000 PSI - half mild steel, 10% or less of hard steel) much odds of working. JBW says 3960PSI (straight from the horses mouth, or website, anyway)

Somewhere back in the deep archives may be something about redoing my backhoe pivots - the lower one was terrible. I had the "shoulder joint" section of the hoe welded and rebored at a machine shop, but could not get anyone to come work on the hoe mount side in situ (thus began my wanting of a portable line borer, which comes and goes and has yet to find one where the price seems right.) There I did have new bushings to put in, but the lower hole was worn right past the bushing. In what I freely admit is a terrible kludge, I filed steel keystock to fill as much of the gap on the worn side as possible as tightly as possible, and then glopped it in place with said plastic titanium. I don't know for sure if it's holding up well, but I think it might be. But all it's doing is stabilizing the steel keystock and hardened steel bushing. Putting loads that deformed 36,000 SPI (or better) steel on a 3960 PSI plastic seems doomed to fail.

Might go look at the dead motor 4500 carcass (UPFord - you posted the CL ad?) and see what its front axle looks like, if it's still there with the nose (I saw front tires over by the backhoe, so perhaps the axle is still with it.)
 
Notice I said that machining the bores was my first choice. However, in my years of working for customers, there have been many times when I have been pressed by the owner to come up with cheaper and/or quicker alternatives. JB weld has been that choice on more than one occasion, with success.

IMHO, I can tell you why that bore is worn, and it has nothing to do with the loads of the machine. Someone, at some point in the past, did not install the drawkeys properly during the last kingpin repair, and the kingpin came loose and started to move around in the axle bore. My guess is that at some point later, someone noticed the loose keys and tried to re-tighten them (or maybe it was a subsequent kingpin repair), but the damage was already done. Once you get a little clearance in there, it's all but impossible to keep the pin from moving around.

I've been around more than one machine that has probably had more than a dozen king pin kits installed during its lifetime. It's pretty safe to say that during some of those repairs, the drawkeys were not properly tightened.

When the drawkeys are properly installed, the tapered surface acts like two wedges between the axle housing and the pin, positively locking that pin in place so it can't move, almost as if it was welded in place. I've worked on more than a few of those machines with many, many hours, and getting those kingpins out often took nearly a stick of dynamite to get them out (had to torch them out actually). Properly installed, they don't want to move!

The loads of the machine put all of the weight on the thrust bearing, not on the pin. In other words, the major loads are vertical on the axle beam, not horizontal on the pin. I still think JB weld is a viable repair option here. The OP is out $5 if it doesn't work.
 
Well Bern,
I'm not so sure of your theory on how they got egg shaped in the first place but I wont argue that here.
I will argue whether jb is an appropriate patch however.
I think trying to fix his axle that way is ridiculous.
But you may fix things how you wish.
 
Think of the drawkeys the same way as any tapered joint. Properly assembled, there should be zero relative movement between the two parts - forever! If that is the case, there is no way either part can wear - at all.

As I said, I've worked on more than one of those axles, with lots and lots of hours, where getting the king pin out was a major task, because the parts were locked together so tight. Once out, I spend 30 seconds in each bore with some emery cloth, and the bore is as good as new, waiting for the new kingpin. Once the drawkeys are properly secured, that king pin WILL NOT move, and consequently, there will be no wear. That's the beauty of a tapered joint. The downside of course, is getting them apart sometimes.

As for JB weld, yes, it's not a professional repair, however if the customer understands the risks up front and signs off on it, I'm more than willing to try it. If it ends up saving him several hundred dollars and days worth of time, I'll have a happy, repeat customer. If it does not work, I'm covered that way also.

There's a JD wheel loader running around my area that I repaired several years ago. The rear axle was about to fall off the machine because the owner could not keep the trunnion caps tight. The dowels and holes in the main frame were all egged out. A machinist with a portable boring bar was going to cost over a grand to repair, and he was over a week out. I filled the holes with JB weld, let it dry overnight, installed new bolts, and it is still going strong to this day. To each his own I guess.
 
Thanks, everyone for all the ideas and experiences.

When I tear it down, I will measure the amount of out of round of the holes and go from there.

One thing for certain, I need to stop the kingpins from moving, or it will only get worse.

Guy
 
Just to make you jealous...
I got my axle back from the sand blaster today.
Shot a coat of primer on it.

100_1739.jpg
 
Kenny said you were right, that the pins got loose and wore the bores on the axle.
Only way it could have happened.
He said no way they could have bent or elongated like I suggested.
He also said you wouldn't need to weld in the new bushings. A good press fit would do the job.
So Bern, I'll concede that one and tip my hat to you.
In my chagrin, I forgot to ask him about the JB weld.
I'll give you his thoughts on that in an update.
 

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