31 spline axles
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Senior User
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From: Denver, CO
31 spline axles
Has anyone every pulled 31 spline axles out of a van/truck and had them cut and resplined to fit in an early bronco big bearing 9" housing?
I have heard that the bearings are not the same; ball vs. roller.....
Any input?
Thanks,
Chris
I have heard that the bearings are not the same; ball vs. roller.....
Any input?
Thanks,
Chris
Postmaster
Joined: Dec 2002
Posts: 3,594
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From: Southern Oregon USA
I've seen this done before. The biggest concern that I have is that you are using 25-30 year old axles. And they aren't as strong as the aftermarket axles you can get.
Yes, there are 2 different styles of bearings, roller and ball. I've seen both styles used in the truck/ van rear ends so there is no set application. They will interchange in the housings, but I'm not sure if the axles are the same. I've always replaced like for like.
Jason
Yes, there are 2 different styles of bearings, roller and ball. I've seen both styles used in the truck/ van rear ends so there is no set application. They will interchange in the housings, but I'm not sure if the axles are the same. I've always replaced like for like.
Jason
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From: Colville
I know of a local machine shop that narrows rear ends for street rods. the splines usually twist off of the shortened axels. The shop doesn't recomend or waranty shortnening and resplining but will do it for those that are trying to save a few bucks.
Have you ever seen a 9" axel twist off between the bearing and wheel flange?
I have twice, and it aint funny!
Have you ever seen a 9" axel twist off between the bearing and wheel flange?
I have twice, and it aint funny!
Postmaster
Joined: Dec 2002
Posts: 3,594
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From: Southern Oregon USA
Not all of them taper down. I couldn't tell you what does and what doesn't. I know of several guys that have narrowed stock 31 spline axles for spares. This was back when 35" tires were considered big for the trail and you weren't breaking stock axles every trip. And high dollar alloy axles were for drag racing only 
.
I have seen a couple of flanges break off 9" axles. The really scary part was the kid (with the help of his obviously not-so-bright father) who decided that they would just weld the flange back on the axle. I wish I was making that up. The good thing is that it broke almost immediately after he put it back together. And I talked him into at least buying a used axle.
Jason
.I have seen a couple of flanges break off 9" axles. The really scary part was the kid (with the help of his obviously not-so-bright father) who decided that they would just weld the flange back on the axle. I wish I was making that up. The good thing is that it broke almost immediately after he put it back together. And I talked him into at least buying a used axle.
Jason
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From: Southern Oregon USA
I would say yes as long as they are quality axles. But the switch from 28 to 31 spline axles depends on what you use it for and what size tires you are running For me, it made sense to upgrade to 31's because I was swapping to a Detroit at the same time.
There is nothing wrong with 28 spline axles. A friend of mine ran 28's with a Detroit, 35" tires and a torquey 351 for years. He ran it at Tellico, Rubicon, Sledgehammer and many other lesser known trails for 10 years before it finally broke one of the original axles.
Jason
There is nothing wrong with 28 spline axles. A friend of mine ran 28's with a Detroit, 35" tires and a torquey 351 for years. He ran it at Tellico, Rubicon, Sledgehammer and many other lesser known trails for 10 years before it finally broke one of the original axles.
Jason
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From: Colville
The point I was making was that there comes a time to replace your used axels with new ones, or at least have the used axels magnafluxed to check for cracks between the bearing and flange. Worn splines are obvious to the naked eye.
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From: Southern Oregon USA
It is a good idea to have them magnafluxed.
After working for a company that builds alot of 9" differentials, I would say that the majority of problems you see with the axles are being bent, worn seal and bearing surfaces, and twisted or worn splines. Very rarely do you see them cracked or broken.
In all of the times I've seen flange failures, they were caused by severe abuse with the original axles (such as landing a jump wrong). I wouldn't rely on a used axle if you plan on doing stuff like that anyways.
Jason
After working for a company that builds alot of 9" differentials, I would say that the majority of problems you see with the axles are being bent, worn seal and bearing surfaces, and twisted or worn splines. Very rarely do you see them cracked or broken.
In all of the times I've seen flange failures, they were caused by severe abuse with the original axles (such as landing a jump wrong). I wouldn't rely on a used axle if you plan on doing stuff like that anyways.
Jason
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that is good to know. i have never broken a factory axel but i try to be easy on the throttel with the new motor for fear. so now if i do break one i will just buy a good 28 spline and keep the locker i have now.
