Weird axle shaft problems

[KC_JoNeS]

I am not trying to sabotage this product, I am merely trying to make these available for everyone running an Axial axle. This thread is intended to make this product as good as it can be.


Ok guys, I have been working on the gunnar beef toobs the last couple weeks, and have been stating in the vendor thread that the stock dog bones will not work with these. The issue I am running into, I am not sure where the fault is, to be honest. Here is the situation that I can see up front.

The stock dog bone and stub combo is slightly longer than the 3Racing CVD set. I know this should not matter, as nothing in the length is effected by using the beef toobs. Perhaps there is something else that I am missing. For instance, when the beef toob goes into the axle, the knuckle is hard mounted to it. There is NO slop. But, with just plastic, maybe there is a bit of wiggle room for the knuckle.

Here is what happens when I try to install my dog bones and stubs.....
When I slide the stub through the knuckle inner bearing, and begin to place the knuckle onto the C, I notice that the mounting holes do not line up. I have seen this now with 2 different axles, but the same shafts...which are new SCX10 shafts and stubs. If I try to insert screws to mount the knuckles, the dog bones get pressed tightly by the stubs, causing a serious bind.

This should not be related to the beef toobs, but I am completely stumped here. I have to be missing something.

EDIT: I also need to state, I am using VP zero ackermann knuckles, and yes...I have used the zero ackermann knuckles before with dog bones and stubs.

Casey

[KC_JoNeS]

As most of you know, the outer bearing for the shaft is flush with the outside edge of the axle housing. With the beef toobs installed, they are in the same location.

No bearing:



bearing installed:

[Duuuuuuuude]

Maybe the toobs are just a hair too long? Since the axles only go in as deep at the bearings will let them...

[KC_JoNeS]

Originally Posted by Duuuuuuuude

Maybe the toobs are just a hair too long? Since the axles only go in as deep at the bearings will let them...

This has always been my opinion as well, but if you look at a stock axle, the bearing is at the outer edge of the housing. With the toobs, it is no different.

OK, a good check for this....tonight I will check the depth from the outer edge of the housing to the bearing seat in a stock housing, and also check the depth from the outer edge of the housing to the toob in a modified setup.

Thanks Duuuuude.

[Crawling Calvin]

Hmmmm wheres the taper on the part where the bearing goes in. Remember what Gunnar did, it was pretty big and steep. I think the inner sleeve of the bearing is rubbing, just me though.

[gunnar]

That's not it Calvin. If the dogbones don't fit, then the end needs to be machined down a few thou shorther(distance between threaded hole and bearing seat face). I'll check them out with bones Friday afternoon/evening, and post up my results.

If that's what the problem is, I'll lathe down all the tubes I have.

[KC_JoNeS]

Originally Posted by Crawling Calvin

Hmmmm wheres the taper on the part where the bearing goes in. Remember what Gunnar did, it was pretty big and steep. I think the inner sleeve of the bearing is rubbing, just me though.

No, this is not the problem. All the parts I sent to Scott are tapered very well. The toobs I am using are tapered enough too.

[cj7man]

i installed my axle tubes today one tube was alittle longer then the other but not long enough to matter i had no problems with my cvds if i can find my old dog bones i'll throw them in and see if i have the same binding problem

[KC_JoNeS]

Originally Posted by cj7man

i installed my axle tubes today one tube was alittle longer then the other but not long enough to matter i had no problems with my cvds if i can find my old dog bones i'll throw them in and see if i have the same binding problem

What do you mean one was longer than the other? Do you mean that when assembled, it looked like this?



From this pic, you can see the left side looks closer than the right side. Did you physically measure these? What was the tolerance difference?

I had these cut at 50.5mm + or - .03mm.

Casey

[KC_JoNeS]

Originally Posted by gunnar

That's not it Calvin. If the dogbones don't fit, then the end needs to be machined down a few thou shorther(distance between threaded hole and bearing seat face). I'll check them out with bones Friday afternoon/evening, and post up my results.

If that's what the problem is, I'll lathe down all the tubes I have.

I will be home in about 7 hours, and will do the check for the depth of the stock bearing seat.

If this does turn out to be the issue, I will make another batch and have them pretty quick.

Casey

[gunnar]

The actual length of the tube is not a huge deal, anything from 49mm to 51mm is fine, as long as the tube doesn't touch the diff bearings, 51mm is about the safe limit though. The critical part is where the threaded holes are in relation to the end of the tube(bearing seat). That distance is going to determine how tight or loose the inner axle will fit. Obviously, the pins on the inner dogbone ball have to line up with the kingpin holes in the C, or you will get a bind when turning.

I have a feeling just 2 or 3 thousands off the end of the tubes will solve any problems with running dogbones.

[Code454]

if one does end up a hair off take a file to it no biggy

[cj7man]

the length of one was 50.44 the other was 50.79 but i have no problems with cvds the tubes work great i was just thinking that the little extra length might effect the stock dog bones

[KC_JoNeS]

Originally Posted by cj7man

the length of one was 50.44 the other was 50.79 but i have no problems with cvds the tubes work great i was just thinking that the little extra length might effect the stock dog bones

50.79? YIKES!

[gunnar]

Originally Posted by KC_JoNeS

50.79? YIKES!

Still within spec, I don't think it will be a problem. I have 18 tubes here, so I measured the shortest(50.31mm) and the longest(50.78mm) tubes from the 18, I will use both of these in my test. I also checked the hole distance from the end of the tube, and could not get any measureable differences(under 1/1000th in.) between all the tubes.

OK, Here we go with my little dogbone test. I got a new housing and removed the bearing seats. I only used a dremel and an Xacto for clean-up:



I removed all 4 seats(2 in each housing half) in under 15 minutes. Now, for lining up the tubes, here is an easy way: Install one tube and line it up as best you can, then start a screw into one side. Be careful! Don't strip the tube, if the screw does not go in, line up again until the screw threads in easily:



Install the other tube, with one screw, then get your diff ready:



Diff installed and ready to attach other half. The short tube is on the left in this pic:



I checked with the other two screws to make sure they lined up. They threaded right in, first time:



Put the halves together and tighten the 4 diff screws. Remove the screws that held the tubes together, and install the C's. I'm using stock plastic C's and knuckles for this test, new inner dogbones and modified stubs(only ones I have, sorry):



The results? I got absolutely no binding at all, even when turning close to 40 degrees, which is what these modded stubs allow.

So, here is what I'll do. Next week I'm going to purchase a complete stock axle. If you want to run dogbones, and install your tubes and find that the tubes cause binding-- PM me. You can send the tubes to me, I will modify the tubes to work properly with them, fit them into the stock axle to make sure they work, and I will send the tubes back. I will reimberse your shipping via paypal, so you pay nothing at all.

[Duuuuuuuude]

Concerning the modified stubs...

Were they clearanced any where the ball end of the shaft sits?

I've had a couple, and I'm not sure why exactly, that I had to grind the recess deeper to get them to not interfere with each other.

Just a thought.

It could also be that the inner bearing of the knuckle is not seated completely, pushing the stub towards the knuckle.

KC ~ try using the stock axial knuckles with the aluminum c's and see what happens.

[gunnar]

They definately could have more clearance near the ball area, which is why I have to get the complete stock axle assembly to make sure. I thought I had all the parts here, but could only find the modded stubs. All other assembly was done properly.

The fix for the tubes is to remove maybe a thousanth or two from the end to free up the axle and stub if there is binding. The dogbone cross pin in my test axle seemed to line up just right.

I'm just wondering if I should turn all the tubes down a small amount anyway, just to try and prevent this from happening.

[Duuuuuuuude]

I would almost bet money that its an aftermarket knuckle or carrier issue. Like I said, I saw it on mine. Now that I have thought about it a bit, I had issues getting the knuckles to line up with the c's too. All the bearings were seated (as far as I could tell) and the only real fix was to grind a bit out of where the ball end of the axle rides in the stub. This was with Axials aluminum c's and knuckles.

[gunnar]

It is a pretty critcal area. On the stock dogbone/stub, the backside of the stub has a small bowl that the ball rides in to keep the axle from moving out. A few thou there could make a difference. When I do the stub mod, I just cut the angled faces with a 45 degree countersink(90 degree total), and leave that bowl area alone.

[Duuuuuuuude]

Originally Posted by gunnar

When I do the stub mod, I just cut the angled faces with a 45 degree countersink, and leave that bowl area alone.

Thats usually all I do as well, but I had to clearance the "bowl" last time. I could get either knuckle bolt in by themselves, but not both at the same time untill I did.