930 front hub conundrum

[1979-930]

Originally Posted by MBruns

I noticed the inner spacer/grease seal ring appears to be missing, did you remove it ?
Mike Bruns

Check this.^^^ There is a spacer #901-341-623-00 that looks like part of the spindle and the mechanic probably missed it when swapping parts. The bearings seats too far in when it's missing.
I would tow the car back to him. He owes you a spindle and bearings.

[KTL]

What does the race inside the axle hub look like? I think you only showed us the race condition for the larger, inboard bearing that did not fail.

This Timken video is a pretty good one to show various types of bearing failures

https://www.youtube.com/watch?v=hVuReXrZ8Mg

Over the years we've seen some bearings that were not machined properly on the inside diameter and don't fit over the spindle. Someone could have forced one of those on there?

New SKF inner front bearing doesn't fit on spindle....

Or you could have experienced a bearing that had its inner race spinning on the spindle too much. That race is supposed to stay put, like the outer race is pressed into the hub, and the roller cage rolls along the races. Rolling is important. I guess there can be instances of sliding, where the rollers are not spinning, and that's bad.

Agreed that spindle is toast and you need a new strut. That spindle carries a lot of load and you don't want any surface defects compromising it's strength. The load on the spindle will seek out that surface damage and crack/failure propagates from there.

The spindle is a nicely machined forged piece and very strong. But as these cars continue to age, we're going to see things break that normally wouldn't. Nothing lasts forever, even though Porsche generally over-built these cars in a lot of ways.

[KTL]

The inner spindle collar looks like it was there at initial disassembly. I think he unnecessarily took it off during the removal of the toasted bearing? See the above pictures.

[somoney311]

I think y’all are spot on again! I noticed last night looking at parts that I would need to get that there was no inner seal ring on this side. I think I need to have a talk with my mechanic about replacing that strut. Looks like multiple steps were not followed.

I have not checked the other side yet but just a wiggle of the tire confirms the hub is not as loose at the right side was. I will be doing that side also.


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[Craig_D]

If you want to see how all of the spindle/hub components come together on a 911SC, take a look at my thread. I did a full rebuild with raised spindles and new bearings. Lots of pics:

'78 SC Elephant Racing Suspension Rebuild

[somoney311]

The inner spindle and a spacer were on the strut but that spacer was very loose. There also was no O ring on it.

This was also missing.


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[somoney311]

This is the space I’m talking about.

The yellow arrow shows a lot of room between the seal and the race. That was before I did anything to the inner race.


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[somoney311]

Originally Posted by KTL

What does the race inside the axle hub look like? I think you only showed us the race condition for the larger, inboard bearing that did not fail.

This Timken video is a pretty good one to show various types of bearing failures

https://www.youtube.com/watch?v=hVuReXrZ8Mg

Over the years we've seen some bearings that were not machined properly on the inside diameter and don't fit over the spindle. Someone could have forced one of those on there?

New SKF inner front bearing doesn't fit on spindle....

Or you could have experienced a bearing that had its inner race spinning on the spindle too much. That race is supposed to stay put, like the outer race is pressed into the hub, and the roller cage rolls along the races. Rolling is important. I guess there can be instances of sliding, where the rollers are not spinning, and that's bad.

Agreed that spindle is toast and you need a new strut. That spindle carries a lot of load and you don't want any surface defects compromising it's strength. The load on the spindle will seek out that surface damage and crack/failure propagates from there.

The spindle is a nicely machined forged piece and very strong. But as these cars continue to age, we're going to see things break that normally wouldn't. Nothing lasts forever, even though Porsche generally over-built these cars in a lot of ways.

That video was very informative. Thanks for posting it and all the time you put into your reply. Looks like I need to talk to the mech now. Unfortunately I moved across the country so he can’t re-install new parts. I think I’ll have him purchase them and ship them to me to be installed. I’m starting to get an irrational fear of someone else working on my car.


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[Craig_D]

Originally Posted by somoney311

I’m starting to get an irrational fear of someone else working on my car.

That's exactly why I did my own rebuild. Not only that, BUT one of my spindles also did not have that spacer when I pulled the hubs, and the bearing housing was tweaked.

Take a look here: '78 SC Elephant Racing Suspension Rebuild

[Craig_D]

Here's the point in my build where I installed the two "hat" spacers onto the new spindles (I switched from stock Boge to Bilstein raised spindles by Elephant Racing):

'78 SC Elephant Racing Suspension Rebuild

[KTL]

James,

Even a new collar/spacer placed on the spindle is going to have that space in there. That's just how it fits. That said, it's good to pack that void with grease. Reason being is the void provides a place for the grease to migrate into and that takes some grease away from the bearing.

The o-ring doesn't really do anything to hold the collar on there. It's intended to be a seal against grease leakage (when the grease separates and releases oil) seeping past the interface of the collar flange and the spindle. In all honesty the o-ring isn't critical to the install. You could put a small bead of silicone around the neck of the spindle and that would seal it better. Because I don't know that the o-ring really completely seals it all that well. The o-ring doesn't seem to tightly fill the void between the radiused fillet of the spindle and the collar flange. I could be way off base with this. Just a gut feeling.

The fit of the collar is a rather light press fit. Guys have been successful in driving it off the spindle with a hammer and punch. Or if you have a suitable size two jaw puller (usually have to grind/shape the pulling arm hook area for it to grab the edges of the collar) it doesn't require a lot of wrenching effort at all to draw the collar off the spindle with the puller. Reinstalling the collar goes really smoothly if you heat it up with a heat gun or toaster oven. Slips right on with no interference and doesn't take long to cool down and shrink fit itself in place.

[somoney311]

Thanks for the tips for reinstall of the parts. I think I’ll get all the parts just to be safe since that’s how they designed it.

Well productive night tonight. I got both races out. The inner one was a PITA. It took a couple hours. Had to use a punch and just rotate the hub all the time. Patience was key here. The outer race came off in about three hits. Super easy.

Some have asked or wondered what was installed on the hub/spindle. Other than the bearing that failed and turned into about a million pieces....ok maybe about a thousand (no kidding there) here are the only parts that were on the spindle.

That was the inner bearing and seal.

That’s the “washer” for the spindle nut. Looks like it got chewed up pretty bad.

And here is the outer race.


The inside of the hub looks good where the races seat so that’s positive. I didn’t expect damage there but you never know.


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