Drive Axle retaining: studs vs bolts?

[buswarrior]

I'm wondering if this is another busnut duty cycle weakness?

In commercial service, the axles will be removed on some periodic maintenance cycle, that is measured in months, or at least annually.

In busnut service, they stay installed for years, or even decades.

The longer stuff stays squeezed together...?

Add in that we are less likely to re-new fasteners, and we set ourselves up for trouble the next time?

Fresh in-your-ownership fasteners, an annual tear down of the wheel-end, new gaskets and seals every time, and the trouble goes away?

happy coaching!
buswarrior

[JohnEd]

So many issues and so little time:  Crap!

The cones go on all studs.

The studs have fine thread on the outside and course thread going into the wheel.  If you use bolts you will have COURSE$ threads under the cone and that will aggravate the removal process.

The PROPER stud length will have a smooth, unthreaded, section in the middle that is intended as the "seating area" for the cone.  IF the cone seats on threads it will gouge the threads into the cone and the axle will shift ever so slightly and that is enuf.  Consider the torque on that axle in low on a hill starting out.  Smooth counts.  Rough bolt threads will e far worse that machine fine.  The fine threads are only contacting the cone for the last couple threads.  Over the years you may have had studs changed out and replaced with improper items.  I have eight studs that are much to long thatks to a shop in South Dakota.  The 5 bolts I got in my last visit to an extremely reputable shop and I am amazed.

Don't ever remove the nuts till you have the axle popped free.  Just loosen them up a little and swing away.

This is like Goldy Locks:  Too small a hammer won't work well.  Too large, heavy, a hammer won't work well.  It has to be the correct weight and it has to be swung like you really mean it.  Size matters.

by Dallas:
I'm not saying don't replace with bolts, since I'm not an engineer, but it seems to me that the engineering has already been done, and this is the best answer possible.


You don't need to be an engineer or a D mech or have 50 years in the field.  I have none of that and I have never actually read any of what I have shared. But it is true....or not.  Problem is really what D shared....A freaken wheel may come off due to a deviation from standard procedure and materials.

I think even the use of the stock gasket would enter into getting the correct relationship between stud threads and cone so I would not recommend using a sealer or form a gasket in place of a proper gasket.

Be well and happy Jim,  Don't forget what Clifford said, now.

John

There, now I feel better.  Was it good for you?

[rv_safetyman]

John, most of what you say makes good sense.  My plan was to get bolts of a length such that the cones would seat on the un-threaded part.  As I noted, I have at least two different studs.  One has a very short "smooth" area.

Failure of these studs would not cause the wheel to come off.  The wheel is retained on the hub and the hub is retained by the bearing set.  Failure of these studs would only result in inability to transmit torque.

Buswarrior, I figured that "old age"  (read fretting corrosion) was the cause of my first problem trying to get there cones out.  However, these axles had been removed in the past couple of weeks.  The cones were well lubed.  The lube itself may contribute to the problem.  A lubed wedge can really cause huge radial forces between the bolt and axle.

Hope I can get to the parts place today.  Snowing here now .

Jim

[rv_safetyman]

Interesting visit at the truck parts place today.  I got the gaskets, studs, cones and nuts.  They did not have enough of all the parts in inventory, but ordered them for me to pick up next week.

The interesting item is the cones.  The ones they sell are solid cones (not split).  They said that is all they sell and that is what the axle manufacturers recommend.  He said that he thought the split cones are "aftermarket".

I have mixed emotions.  The cones are not snug on the stud.  I suspect it will tighten a bit, but that will rely on "crushing" the cone a bit.  On the positive side, I think the solid cone will release easier. 

When I removed a couple of the present studs (had to remove them to get the axle out), the cone was pretty locked on the stud. 

Fortunately, the new studs are a bit longer and that will let me double nut the stud to remove it, if needed.

Jim

[gus]

Jim,

No, I wasn't suggesting you remove four of the cones, just telling you what my manual says. And, as I said my bus has no cones at all. There was no sign of slippage or looseness so I can only assume there was a design change after the manual was written. I also have some antique GMC heavy trucks and their manuals have the same instructions.

One thing I forgot to mention, the manual also says the cones must protrude "slightly" above the axle flange or be replaced. I can see the reason for this. However, if the cone happened to protrude a lot more than "slightly" it could be excessively crushed by the nut and make it lock up.

[JohnEd]

From my standpoint....not all that lofty a perch.....I would not use the unsplit cone.  If it is solid it cannot "release" after the axle is whacked and sprung free.  I think solids would be a onetime affair and possibly a real bitcX to remove.  You pull the axle ever year or two so don't shoot off any toes.

The cone MUST protrude slightly or it will not squeeze the stud and prevent ALL relative movement.

The stud smooth part must be the correct length and sit slightly under the flange.

Bolts have an unthreaded  area that is smaller in diameter than the threaded area.   Sometimes.  My U JOINTS are held on with bolts called "shoulder bolts". They have a smooth area that is the same diameter as the threaded area or possibly greater. Install them backwards and the u joint flange will twist itself and chew out the hole and destroy the flange.  And this is similar in principles to the axel stud flange relationship. My point is that I don't think any bolt will fill the bill and if you are looking that hard for that bolt you might as well get the correct stud.

You are right to "correct" me.  A full floating axel doesn't retain the wheel.  In that case the tire wouldn't come off but if you loosened up the axle while underway you might prefer dieing in a firey crash. Figuratively.  I do appreciate the thought.

John

[Bob Belter]

Ahoy, Jim, All,

In my case, I loosened the nuts on the drive studs a turn or so, and 'whacked' the nuts very smartly on the side with a big hammer several times.  Freed everything OK, and I was able to get each drive --  torque axle out OK.

A poor job of seating the oil seal saw me needing to remove one of them, and the method worked OK the second time. 

I never did whack the axle on the end  --  I'm not that good with  a sledge hammer. 

Sheeeesh!!!  you ought to see me golf!!!!

Enjoy   /s/   Bob