Spindle / bearing load surfaces.. how to tell if...

[GenPac]

I'll try to make this query short and sweet...
How do you know, or how can you tell if your spindle bearing surfaces are too worn for new bearings? I had some slop on one side, and I know the bearings are designed to wear out and not the spindle (unless there's a catastrophic failure) But over time (think 40 years) could the spindle require replacement too?
Here are the pics of my bearing surfaces... Hopefully they are of suffecient fidelity for any experts to be able to determine if their continued use is warranted or should they be retired... ?
pics:





Application is a '69 Chevelle, factory front disc spindle.

[astroracer]

REd X's on the pics but, to answer your question, the spindle surface should see zero wear. The inner races of the bearings carry all of the load and rotational forces and the only time the spindle surface sees any kind of rotatational force is when, as you stated, a catastrophic failure occurs such as a seized up bearing or inaccurate assembly torques.
Mark

[GenPac]

Hmm.. the photos are hosted on photobucket. I'll double check the sharing permissions to make sure they are public.
"Zero Wear" is what I am having problems identifying. I see some marks which could be construed as wear, I suppose but there is definetly no grooves or clear lines as if there was a failure.
I hope the marks I have pictured can be just emery cloth polished away...

[parsonsj]

Dan,

Do you know if those marks used to be there? It's possible they are just the original machines marks.

jp

[GenPac]

Honestly, the first time I looked at them, I thought "Heat markings". On closer inspection, it looks like metal on metal galling. To the touch, I cannot discern any pitting or grooving (by feel or running an edge across it) but it almost looks like a heat related gall.
I don't believe these were here all along, IMO.

[Rhino]

If there's no grooves cut, I'd venture to say you would be ok. The vertical load on the spindle/bearing assembly should be more than sufficient to prevent the inner bearing component. With that said, you should have extremely low wear, even over time.
I can't see the pics either, although I have seen similar markings on spindles in the past. If you can't feel a difference, I wouldn't worry too much.

To be 100% sure it's ok, I would simply take a few measurements down the spindle, using a mic. If there is sufficient wear in an area, it should show up in your readings. Ideally there should be a very small deviation between them.

[GenPac]

Pics are hosted at photobucket but I'll attach here, instead.
Please, if you get a chance, check out the photos. Both are taken in Macro mode, with and without flash.

To be 100% sure it's ok, I would simply take a few measurements down the spindle, using a mic. If there is sufficient wear in an area, it should show up in your readings. Ideally there should be a very small deviation between them.

I've thought about taking measurements but I have no reference point. I could check for any tapering, I suppose... assuming that these surfaces are supposed to be perfectly cylindrical.

[Apogee]

The bearing journals on the spindle should be cylindrical and smooth. It looks like there's pitting from the pictures, but if you say you can't discern it with your fingernail or an edge of some sort, I believe you. It looks like you may have already done some work on it, but I'd take a Scotch-Brite pad and/or emery cloth and clean up the journals...could just need a spit and polish. It wouldn't hurt to have your spindles mag-fluxed and checked for cracks while they're off and clean-ish.

Wheel bearings are installed with zero preload and as such, tend to spin on the pin when (un)loaded just right. You can see the grooves in the shoulder of the spindle pin caused by the inner wheel bearing cone spinning in the past. The only way that I know of to eliminate this entirely is to run bearing spacers and torque everything down.

Tobin
KORE3

[GenPac]

Yes, the pitting is there... Just not enough to make the surface rough. It would probably catch with a razor edge, but my fingernail, metal ruler and fingertips can't feel them / doesn't catch on them.

I am going to use some emery cloth and lap / polish the journals, hopefully enough to clear some of the discoloration (which I thought might have to do with heat/rust/galling) and give the replacement bearings a better surface to sit on.

As far as bearing spacers... do you have a link to an example or previous application? I'd like to know more...

[Apogee]

We've supplied bearing spacers in the past to our vintage racers and a few others who wanted the ability to pull hubs while hot and still be able to reassemble them without worrying about resetting the zero bearing preload and axial end play. The spacers themselves are just a CNC machined steel sleeve that slips over the spindle pin between the inner and outer bearing cones and a stack of shims for setting the end play. This allows you to torque down the spindle nut while maintaining a fixed amount of axial play. The added cross-sectional area of the sleeve reinforces the spindle pin as well, making it more rigid and less prone to deflection when cornering which can be particularly helpful in reducing pad knock back in fixed caliper applications, much like the C3 calipers extensively used in vintage muscle racing circles.

Tobin
KORE3

[GenPac]

So, after a little emery cloth and scotchbrite, the spindles cleaned up easily. I have the most visible wear on the Drivers side inner bearing journal. The pitting is now more visible on the passenger side.
PICS:
Passenger side...



Drivers side...




DOes the wear look within tolerance?

[Apogee]

Now that they've been cleaned up a bit more and the discoloration is gone, that looks a lot like common corrosion pitting. It's not even all that bad by most standards...I'd probably run it as is. There doesn't appear to be any serious wear that would have been caused by a seized bearing or any scoring lines in the spindle pin itself that would give me pause.

Grease it all back up and keep an eye on it. I'd be willing to bet it looks excactly the same 50,000 miles from now.

Tobin
KORE3

[GenPac]

Now that they've been cleaned up a bit more and the discoloration is gone, that looks a lot like common corrosion pitting. It's not even all that bad by most standards...I'd probably run it as is. There doesn't appear to be any serious wear that would have been caused by a seized bearing or any scoring lines in the spindle pin itself that would give me pause.

Grease it all back up and keep an eye on it. I'd be willing to bet it looks excactly the same 50,000 miles from now.

Tobin
KORE3

Thanks, Tobin. I appreciate your experience on the subject.