Lock pins too large for axle?

bosstime2

bosstime2

Member
Put a nice new axle in the car and the king pin locking pins seem too large for the holes…bores are less then 9/16. New kingpin set from Synders. Im not sure what to do next. Im surprised the bores are smaller than 9/16…anyone ever encounter this?
 
The spindle locking pin hole should be reamed .561-.563.
 

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Measurement wise,it make no difference if the bolts are put in from the front or back.The hole in the axle is straight,all the way through.But,they need to go in from the front because the nuts are the stops for the spindles.What do the holes in yours actually measure? They should be at Bob's specs.What do your replacement pins measure at?
 
Yes, from the factory, the hole is the same dimension front or back. With each new installation of kingpins, the lock nut on the lock pins is tightened (often severely) against the edge of the hole in the axle. This causes the area at the edge of the hole that the nut rubs against to create a slightly smaller "ridge" around the outer circumference of the hole. Now the lock pin will go through the hole in one direction but not the other direction. A slight filing of that ridge with a round file should restore the correct diameter of the lock pin hole and allow the pin to insert in either direction. For all axles other than early 1928, the pin inserts from the front of the axle with the locknut on the back of the axle.
 
bobbader said:
Yes, from the factory, the hole is the same dimension front or back. With each new installation of kingpins, the lock nut on the lock pins is tightened (often severely) against the edge of the hole in the axle. This causes the area at the edge of the hole that the nut rubs against to create a slightly smaller "ridge" around the outer circumference of the hole. Now the lock pin will go through the hole in one direction but not the other direction. A slight filing of that ridge with a round file should restore the correct diameter of the lock pin hole and allow the pin to insert in either direction. For all axles other than early 1928, the pin inserts from the front of the axle with the locknut on the back of the axle.
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I'm pleased someone has mentioned over tightening of these cotter pins. (what you guys are calling "lock pins") That causes the eyes at the ends of the axle to stretch. I have seen them stretched so far that it was impossible to hold the king pin well enough to prevent wheel shimmy (What you guys often call the Death Wobble). There is NO need to tighten them very tight at all. Once the eye is stretched, it must be shrunk back to spec (a good time to have any twists or bends taken out of the axle). Nearly a century after these cars were built, finding a decent replacement is becoming more and more difficult so repair is becoming more common - if you can find someone able to do it.
 
Thanks, I’ll try a round file and see how that goes. Makes sense that maybe just the ends are off because of the tightening of the nut
 
I have a coupe with a lot of "interesting" things done to it. This was the second time I had seen the nuts on the front. But when I looked behind the axle more nuts! So it has the long hex nuts on both sides. Anyone seen that before. Kingpins are tight so I left it alone.
 
Maybe you had an early locking pin with a later nut on the other side.
 

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I have a dropped axle in my A V8. The holes were too small,probably due to the dropping. A a quick pass with a reamer fixed it. It should be a snug fit.

John
 
Well, I took a file to the bores this morning…that did the trick. Front end all put back together. Thanks for the tips
 
FWIW, I ream mine with a 9/16” reamer (0.5625”), from front to back, when I rebuild a front axle. Typically goes right in the front but sometimes requires a bit of a push to get it out the back.
 
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