Rear axle thread repair

Phred

Phred

Senior Member
I have heard that when the threaded ends of the rear axle are boogered up beyond rethreading to the original thread size, there is a slightly smaller metric size thread that can that can be used. What is that metric thread size?
Thanke in advance Fordbarn!
 
its supposedly 15 mm ,but the dies are a bit hard to get ,,i had the same problem a while back but decided to pull the diff down and replace the axles ,,i am glad i did because the bearings were stuffed to ,
 
The original axel nut is a special hardened nut (5/8 x 18); check the parts price list. Axel nuts should be torqued to at least 80 lbs. Using a 5/8-18 butter nut is a good way to ruin the axel threads.

Ron
 
IMO, it sure would be better if the thread was "rolled" rather than "screw cut". If a rolled thread is not possible....threads turned, or cleaned up a lathe would be preferred, over cutting a new thread with a die nut.
 
Axles are one place I don't take short cuts. If the axle fails you loose a wheel. If in doubt, I replace the axle with one that has been magnafluxed. Use the proper nuts.

Charlie Stephens
 
Re: Rear axle thread repair- one cause of damaged threads

Have you seen axles with the first 1/2 inch of threads destroyed?

One cause is that someone unscrews the nut a couple of turns and hammers on the nut to remove the drum. This deforms the end of the castle nut. Then when they thread the nut back on the shaft the threads are destroyed.

There are many of these damaged nuts being sold as good used parts.

When replacing a nut on a shaft, if it threads on easily for 3/8ths of an inch and then starts to bind up ... STOP, do not force it any further ... throw away the nut and find a new or undamaged one.

If you force the nut on to the shaft the first 3/8ths to 1/2 inch of the threads WILL be damaged.
 
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Hi Phred,
I'm not able to get downstairs right now to look at my die set, but there is a 9/16-18 (or 20?) SAE thread size which would work just fine on the Model A axle. Check your die chart. If you don't have one, get a buddy who is experienced with starting dies true to a shaft to cut the threads for you. 9/16 Castle nuts can be found, but they can be tricky to find in a grade 8 or grade C hardness. You could always have one of your machinist friends fabricate one for you. Good Luck!
 
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