Stress corrosion cracking in steering shaft?

[Hawkins]

Hey all,

I just got the lower bearing off my steering shaft and noticed a fairly deep line of corrosion, either a stress corrosion crack or or a poorly machined weld that's begining to rust. It's just above the top of the bearing. Hopefully the pics will work out so you can see what I'm talking about. Anyone else ever see anything like this?

I want to reassemble and ride but if it's the onset of stress corrosion cracking, I need a new one, or get this ground out and repaired, or at least get some info on how tough the steel is.

Any thoughts?








.

[b.walker5]

I'd be a little nervous about that, it looks like the beginnings of trouble to me. I'd take it too a specialist machine shop for an opinion and maybe even an xray to determine the extent. I don't think I'd be riding knowing its there.

[tinman905]

"How ya gettin on " Better and cheaper just to replace it. This mainlander from the Crossing has an extra one if you want it ,just pay for shipping.

[Hawkins]

yeah, i don't like it either. Can't imagine it would be much fun to lose steering control. If it turns out to be SCC, it's pretty coincidental that I recently started a thread wondering if these sorts of issues were starting to appear on these bikes. Guess I better have a look at the swing arm bearings and shafts too.

[Hawkins]

"How ya gettin on " Better and cheaper just to replace it. This mainlander from the Crossing has an extra one if you want it ,just pay for shipping.

hey man, hows she goin! That's a mighty nice offer (for a mainlander), and I'll probably take you up on it - I doubt the local boneyard has anything, and machinists charge more than doctors these days. Is it from a Special, or is that part common to both models?

[tinman905]

I have one for a Special and I don't believe it is the same as the standard model.

[b.walker5]

Thats correct, they are different, at least as far as part numbers go, and they aren't listed as interchangable.

[crazy steve]

Personally, I wouldn't worry one bit about that mark. Unless you can see a crack actually going into the metal, that looks like just a common corrosion mark that you'll sometimes find under pressed-on bearings. A bit of moisture got in there somewhere along the line. I've seen this many times on automotive axles and transmission shafts when replacing bearings, and never had one break in normal use. If you're really worried, have it magnafluxed.

Now, some banzai powershifts would sometimes give different results, but that usually resulted in missing teeth or twisted-off splines...

'78E original owner

[oseaghdha]

Don't try to weld it.
That will mostly cause more problems.

[Hawkins]

Tinman is going to send me a replacement, so I won't have to take any chances with the one I have.

The mark is actually just above the top of the lower bearing, not underneath it, and it looks like a crack. Of course, if it's the right type of steel, it might take another 30 years for that crack to grow through the shaft thickness, but who knows for sure. And if it was just me on the bike, I'd be more inclined to take a risk but with wife and kids spending time on the back, I'm erring on the side of caution.

I will get it checked out whenever I run into one of my buds who are into non destructive testing, and if it's ok I'll have a spare to share with an XSessive in need someday.

[DiverRay]

Looking at the Photo, I would think it's from the moisture that gets past the upper seal. I've had water collect in that area, as the grease around the lower bearing keeps the water in. I WOULD agree that it should be check BEFORE going back into service. It SHOULD be ok, but as you said, it is a safety issue.
One thought I've had is to drill and tap the housing for a grease fitting. You could then just fill the area with grease, and not have water in there. That IS going to happen on my '78, and probably on the '79 when I redo the steering stem bearings.