That's 1/8 NPT which is roughly 3/8" OD and 27 tpi. That type is fine if you don't submerge the axle, but if you plan on doing that, then running it up to the frame is a good idea. You can stick the capped fitting on the end of the hose to keep the mud daubers out.


Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.