HELP! Read axle/hub problem

[FV80]

I'm at a loss (after over 30 years of FV). I stripped the splines from a hub in the second race of the Atlanta major - I thought it might have been NOT tightened enough. Got the old one off, no problem. Put on a new one and it won't "snug up" as it seats on the axle. Inspected axle - no noticeable wear on the splines - looks good. Tried again -- drum still rocks slightly when all the way up. I figure, it's somehow not seated enough and the axle hasn't pulled fully through the bearing, so tried tightening again to full torque - loosened nut and hub still rocks. Checked against another trans - pulled nut and found what I expected - hub fully seats without nut and doesn't rock AT ALL. Pulled backing plate assembly - got main bearing off - all looks good - checked spacer for measurement against several others and I already had the thinnest one. Pulled the spacer behind the bearing and inspected it .. obvious damage, but not TERRIBLE - but needed replaced. Put in new one - tightened, loosened and same thing. Finally measured splines sticking out from inner hub cover. I find that the splines on the "good" trans stick out about 1/8 MORE than the ones on the suspect trans. (not surprising). Swapped drums between good and bad, and found what I expected.. the bad one won't seat on the splines, no matter how much torque is applied. Went back and pulled the VW washer that's outside the spacer to pick up a few thou' of space .. still same thing.

At this point, I have no idea where to go except to remove the axle tube and axle - but I can't imagine what I might find there. The axle is free to move in/out as expected (carefully, so as to not loose the fulcrum plates behind the paddle). Putting on new drum (tried several hubs - all same result) is a worthless effort since it's obvious that the drum is not properly seated on the splines and will just wobble loose quickly, destroying another drum in the process.

Can any of you out there think of anything I haven't considered?? It just seems that the axle MUST be "mis-manfactured" and have the wrong length from that inner spacer behind the wheel bearing to the end of the splines.

Ideas??

Steve, FV80

[BLS]

Maybe a dumb answer, but wouldn't it be more likely the axle tube length than the axle? The position of the bearing housing etc. is determined by the axle tube, pressed on to the tube IIRC.

[FV80]

Maybe a dumb answer, but wouldn't it be more likely the axle tube length than the axle? The position of the bearing housing etc. is determined by the axle tube, pressed on to the tube IIRC.

Yes - it would be .. however, the hub on the spline position is determined by the items in order..
1). axle - free floats in the diff regardless of the tube length (within reason)
2). the outer axle flange near the splines
3). The beveled spacer that matches the radius'd flange in item 2
4). The main axle bearing that rides again said spacer in item 3
5). The outer spaces that rides the outer surface of the main bearing
6). The (somewhat questionable) spacer washer .. that is usually worthless and destroys itself in aftermarket axle seal kits .. and is often left out .. successfully
7). The hub/drum itself which seats on the splines.. usually FULLY when all said items above are tightened.

I did check and make sure that a hub WOULD seat on the axle without the outer spacer in place. The drum seats nicely.. just as it should. And that ~1/8" of missing length from the outer spacer to the end of the splines seems about what it would take to get it to work...

Steve, FV80

[BLS]

AFTER posting I went and looked to see if I could make any sense of it. I'm guessing here, if the axle tube is long and the housing is pressed on to the outer end of the tube properly, then the axle would appear short even with the amount of float available... Seems I have read of longer than stock axle tubes, but maybe they are way longer. Just a thought.

[Dave]

Check the axle tube,

the bell is probably bent. Dave

[BobShedd]

I have seen an bearing casting moved down onto the axle tube which would act like too long of an axle, same sympton as if the bell is bent and the tube pushed into it.
If the axle tube is off the car, set it next to another tube - bet the one coming off the car is short...

Good luck & saa ya at Savannah

bOB

[brian]

Guys, remember that the relative position of the casting on the steel axle tube determines the depth of the axle in fulcrum plate of the side gear in the tranny. If the casting has been pushed deeper onto the axle tube from a shunt or having been pressed on too far, the axle will be plunged into the side gear too far. An easy way to check if this has happened is to move the axle up and down the full range of the bell flange without feeling the axle getting tight. If you raise the tube and you can feel and increase in friction, then the casting is too far down on the tube. I measure the difference between the tube and edge of the casting id and look for 17mm. If it is less than 17mm. I press off the casting, rotate it 90 degrees, and repress to the proper depth. Drive the pin through and create a new notch in the tube. Make sure the axle will still slide through with two dimples in the tube. If it doesn't, grind a bit off the dimple that will not be used.

Now, let's think about Steve's problem. When you torque the axle nut, it squeezes all the components: spacers, bearing and drum are compressed together. If the drum still wobbles, either the splines in the drum or on the axle, are compromised. It's not very likely that the bearing is sloppy in the casting but you can confirm it's tight by doing a prefit in the casting to confirm the bearing is being held tightly. Make sure you include the backing plate in that pre-assembly. While the bearing is compressed in the casting, stick your spare axle in the bearing to make sure the bearing isn't sloppy. Now we know the bearing is tight, let's look at the drum. If you do have a spare axle, assemble the components, spacers, bearing , seal race and drum on the bench. You will probably need a vice to hold all the stuff. It shouldn't take a lot of torque to confirm the drum gets tight. By process of deduction, (they tried to teach me that at college) you can determine whether the drum or the axle has the issue. If the axle is twisted, even less than the eye can see, it could be the drum is not getting seated. If the drum is loose in installation of different axles, then it's splines aren't happy.

I find that some new drums need to be dressed a bit. Assuming you've really cleaned the axle, I use my glass beading booth to clean salvage axles, and the drum looks good; paint the splines and axle with some blue dykem. Slide the drum on the axle with all the correct spacers, tap it a couple of times with a hammer. Remove the drum and look for shiny spots in the blue areas you've painted. If the drum is binding up, and you have to tap it off, you've found a likely problem. If there is binding, You'll see the high spots as shiny spots in a field of blue and will be able to trace the restriction. Try filing around the shiny spots and try it again. Keep doing this process until there are no shiny spots.

I often reach for the dykem to trace binding and friction. It's the machinist's best friend. Hope this helps.