Bought a new front axle for a '40 Ford 1/2 ton. The new king pins seem to be fairly loose in the new axle. Had the spindles re-bushed and reamed for a nice kin pin fit. Is there a max. spec. for pin to axle clearance?
Is the axle new, or just new to you? There should be no play in the axle in the ideal world. You can get by with a little, but the wedge pin may make it so the bearing does not sit perfectly flat. The axle can be bushed to correct the issue.
The tolerances are pretty wide in most I've seen over 40 yrs. Some are tight, some loose. As long as the wedge bolt tightens the pin into the axle that's what matters. And don't be afraid to set the wedge with a big hammer. Even if it's a bolt style. Hit it a good one, then tighten nut tight and smack again to seat it.
I had a similar problem on my model A on one side only. I think that the original builder did not tighten up the swedge pins tight enough and the result was increased wear. Since the front end was all chromed I did not want to take it out to be rebushed. I had some really thin shimstock, only a couple of thousands thick and I used it to take up the clearance. The pin fit nice and tight then and I tightened up the swedge pins very firm. It is really solid now.
I did the same on an A axle, the right thickness shim to make the pin a slip fit then cut out a relief for the cotter pin, fit like a new one.
Spec's are all over the place I have 5 axles some new some not...and if the pin temp is warmer than the axle temp the pin will be tight...and the opposite would be true, forgeings will really expand and contract...also if you are using an off shore pin set they tend to be loose...USA made tend to be tighter..if you have ever looked down the pin hole on a really good axle you will see the machine work is anything but perfect...look for obvious wear and if none you should be fine..if the lock pin is not recessing into the axle then that is a good sign as well..after you drive for a while go back and check the lock pin...well thats what I like to call it
Since the axle is new, I would measure both the axle king pin bore and the pin and compare both to standard Ford dimensions. One, or both, could be undersized or oversized. Or could be a bad tolerance stack up. Ford specs nominally found are 0.812 pin and 0.814 axle. Axle can be heated and shrunk instead of bushing. But if it's new axle and found to be oversize spec I would see about having it replaced.
I think I would return the axle and get a different one from a different supplier. Even though they're made overseas I've had really good luck to date with a So-Cal Forged axle or get an original dropped by Anson Axles.
If the king pin bores are over sized i would also be checking the perch bolt bores, no room for play there. I would replace it with a quality item. JW
Yes but anything more than a couple thousands is too much. The lock bolt is loaded with vehicle weight and will wear/compress in time from road shock because it is made from soft material. I could hear the front tires making a different sound when the locks loosened up. I made tooling to bore and bush the axle to hand press fit in the car. Over ten years and have stayed tight.
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