Drive Axle retaining: studs vs bolts?

[rv_safetyman]

OK guys and gals, this may seem like minutia, but it is a huge problem on some of our coaches.  My axles (and I think most) are retained by 8 studs with nuts and split cone wedges.  Seems like a good system until you have to remove an axle.  Then it can be a HUGE problem.  The "standard" method is to take off all of the nuts and pound on the end of the axle with a **HUGE** sledge hammer (says that right in the manual as I recall).  I have had to do this a couple of times and it takes hours if they have been on for a long time!  Most recently when we had to be towed the tow truck guys spent well over an hour trying to remove them.  We then installed the axles when they dropped the bus and I drove the bus about half mile to the shop.  They used an electric impact and did not over tighten the nuts.

Yesterday, I went to remove the axles to repair the gaskets.  They were again very hard to remove.  For two of them, I had to double nut the stud and remove the stud (cone locked on the stud). 

SOOOO, my question:  would there be any problem with replacing the studs with bolts (being careful to make sure the bolts had good thread engagement and did not bottom out).  I suspect a person would need to have a couple of guide studs to insert the axle (replaced with bolts before final installation).

Using bolts would GUARANTEE an easy removal of the cones.  From an engineering standpoint, I can't see an issue if the correct length bolt was chosen.  However, every truck/bus has the studs.

Thoughts?

Jim

[Just Dallas]

Removed

[rv_safetyman]

OK, as soon as I post, I think of one possible issue.  The diameter of the stud can be carefully controlled while the bolt may not have the shaft dimension controlled.  That could possible affect the "locking" of the cone on the bore of the axle and the shaft of the bolt.

The stud has coarse threads in the housing and fine threads for the nuts.  Obviously I will need coarse thread bolts.  I will explore what the tolerances are for grade 5 and 8 bolts (as well as allen head).  The split taper should accommodate some difference in diameter.

Jim

[junkman42]

Jim, I think that the cones transfer all of the radial loads to the studs and without them the axle could shift when loads are applied.  Would replacing the studs with cap head bolts do the same?  Regards John L

[rv_safetyman]

Dallas, we were typing at the same time.  My axles do not have any "jack" holes.  The pounding method for my application is strictly relying on the "ringing" process to loosen the cones.  With jack bolts I could see where it would help the process.  For the short distance I drove, we did not worry about sealing the axles.  I will get the standard gaskets and not use any type of sealant unless you think it is necessary.

John, I probably did not make myself clear.  I would still use the cones with the bolts.  My point with the bolts is that the extracting process (turning and moving outward, will assure that the cone will either stay on the bolt, or remain in the axle.  In either case, the axle can be removed without fighting the removal of the cones.

If the bolts were the proper length, the clamping forces and shear forces should be the same (I think).

Concerning the controlled diameter of the studs, I just looked at a couple of them and the surface finish does not look like anything special.

Jim

[Just Dallas]

Removed

[luvrbus]

Jim, I had 3 bad studs and replaced with grade 8 bolts course thread and they leaked , never stayed tight and the space between the 2 different type threads are larger.
I did change my cones and studs a few years back and came up with idea to drill a pull hole in the axle trust me it don't work the way Eagle axles and hubs are made LOL and Jerry Jefferson is proud of that axle.
I have 4 long studs where I made a hook and plate that goes over the studs grabs the axle you back the 4 nuts off and it pulls the axle out saw that used at Southern Oregon because David was sick of buying aluminum wheels.fwiw there is a couple on the market of different types 


good luck

[rv_safetyman]

Clifford, I am trying to picture the puller you and SOD made.  I did some searching and could not come up with anything.

I would think you would need to have the studs push on the wheel and the back of the axle.  There is not much room to grab a hold on the back of the axle.

Anyone got a source for that kind of tool?

Jim

[bobofthenorth]

Jim my problem always is that I'm afraid to hit it hard enough for fear of smacking the studs.  With the duals on it is a really awkward angle to swing a big hammer, at least for me it is.  What I have found works is to have an old axle around that you can have a helper hold against the head of the stuck axle and then flail away at the exposed end of the salvage axle.  Your helper is actually pretty safe too because the head of the salvage axle kind of protects him from stray whacks.  Sometimes you have to really whack them hard. (the axle - not the helper)

[rv_safetyman]

I guess I will crack out and buy the studs, nuts, and cones.  

My hope is that the studs will be long enough that I can double nut them and remove the stud if I have a problem.

Jim

[rv_safetyman]

Bob, I agree that trying to hit the axle is a big problem.  I have gotten pretty good at it.  I noticed that the guys who removed them this time hit the stud at least once.

The other issue is that my axles look like they have been through the last war.  I can't believe that hitting them as much as I have has not weakened them.   Might even think about carrying extras if I can find them AND afford them.  They are two different lengths, so you would need to carry two.

Jim

[luvrbus]

Jim, on mine I have 3/4 of a inch between each stud on the hub to grab the axle that is where I got into trouble drilling the pull holes, for years I laid a piece of 5/8 x 2 inch  plate on the studs and pulled mine with my trusty Proto puller with 1/4 inch hooks on 2 blades scratch your head you will come up with something.
If not wrong I believe OTC makes the puller for around 200 bucks.
You buy 2 axles from Jerry you would think it was 2 sacks of gold lol



good luck

[bobofthenorth]

I have gotten pretty good at it.

I really don't want to ever get good at that job.

The other issue is that my axles look like they have been through the last war.  I can't believe that hitting them as much as I have has not weakened them.   Might even think about carrying extras if I can find them AND afford them.  They are two different lengths, so you would need to carry two.

Each to his own but I sure wouldn't bother. I've seen a few spun axles and I can't imagine how we could ever do it in bus service.

[gus]

Jim,

I just recently went through this on my 4104. I know it is probably different than your setup but I learned a couple of things.

The cones only go on four studs, not all eight, so if yours is the same that could jam four studs.

The 4104 was changed at some time after my maintenance manual was published showing the four cones, so my 4104 had no cones at all?

A  too thick axle gasket could keep the "bell" reaction from working when hitting it with a hammer.

[rv_safetyman]

Gus, my axles have cones on all 8 studs.  I think I will leave it that way since I have a lot of torque available.  I had not thought about the gasket killing the "ringing" of the axle.

I looked at my studs today and I have at least two different configurations in terms of length relationships of the coarse/fire/no thread area.  Some are pretty buggered up. 

I am going to the truck parts place tomorrow to see what they have in the way of studs.  If I am not happy with the length of the fine threads (so I can double nut/remove), I will go to my bolt supplier and see what I can find.

Jim