Nate's front axle rebuild "I don't know what I'm doing and need help" thread

[NaterGator]

Eyup. This is my first time so as I pull stuff apart and start to tear into the axle I'm going to need A Few Good Mudders to give me some guidance.


A brief relevant history. About 20k miles ago I had a fairly catastrophic bearing failure on the interstate on the way to catch a flight to my brothers wedding. See here: https://forum.ih8mud.com/80-series-tech/162109-cruiser-failure;-i-had-get-towed-now-dealership.html

To start, I've just started pulling apart my DS hub. One of the nuts annoyingly ruined the threads on a stud so I'll be getting new nuts and a stud for the hub. Not a biggie, kinda to be expected I guess.

However about 15k miles ago (maybe a bit less, maybe 10k) I had my dealership check and grease my wheel bearings because I was going out of town and felt it needed a once over (the $2k repair fresh in my mind). Here's what I've found that concerns me a bit.

First off this is all DS and this is as far as I got before it started pouring rain (like one of the only times this year, of course b/c I'm working on the cruiser ). This is a bit of wear I'm seeing on the bottom of the spindle from the outer bearing I suppose:


That looks like very abnormal wear to me, especially for a "new spindle" with about 20k miles on it. Following along here is the outer DS bearing:

Again obvious corresponding wear pattern to the spindle. Is this indicative of excessive heat (ie: from improper lubrication?)

This brings me to my final question/issue: this all looks suspiciously colored like moly grease, no? AFAIK moly grease looks greenish/grayish/bluish and regular bearing grease looks red. The M1 syn grease I have for the repack is most certainly red. Here's the overview of the spindle which otherwise seems to be in good shape other than the wear on the outer bottom surface:


So is this a matter to concern myself with? Does this warrant replacing timken wheel bearings that can't be more than 20k miles old? Or am I being a paranoid newbie and everything looks pretty good?

As soon as the rain abates I'll be tearing deeper into the knuckle and moving to the PS side. Hoping to find all is well elsewhere. So far the FAQ and FSM have made this process pleasantly predictable and easy-to-do. I just don't really know from experience what I'm looking at as this is my first-ever bearing/axle R&R on any vehicle

TIA.
-----Nate

 

[OGBeno]

Clean the moly goop off and then get us better pictures.

 

[CreeperSleeper]

That does look like moly to me... It also looks like the preload was wrong on your bearings. But I'm not an expert.

 

[NaterGator]

Beno, will do.

The rain let up for a minute and I went out and prodded around the hub a bit more.

It is most definitely, unquestionably moly grease. The hub is full of fresh moly grease and it's the classic dark blue color of the valvoline syn moly grease I bought to pack the birfs/hubs. So looks like the dealer fxxxed up on that one and I'm glad I caught it when I did. I'm going to pull my service slip and see the date/mileage when I had the bearings repacked. If it's been a decent while I suppose they may be irregularly shaped and I'll have to get new bearings. Probably as good a time as ever to switch to koyo bearings though. I must admit they look pretty good and the bearings themselves don't show nasty wear

 

[Elijah]

Standard, non-synthetic 'wheel bearing' grease is grayish in color. I wouldn't be to alarmed with the grease but the pitting on the bearing and spindle make me think the dealership might not have ever changed them out.

edit - I can't tell if that is pitting, corrosion, or scorching.

 

[NaterGator]

Well we had a tornado warning and about 2.5" of rain at the house (severe flooding in other parts of Tampa and downed trees ) of course on the day I start this project. I'm going to bed and hoping to get a few hrs of sleep because I want to finish the axle rebuild tomorrow and get working on the rest of my projects.

Anyways I finished completely disassembling the driver's side and everything else looked great. The birf cage was full of grease but the grease seemed to be a bit on the dry side, all the other surfaces/races/bearings looked good though and the inner seal had held. So at this point my only concern is with this spindle wear/whatever and whether I should replace the wheel bearings or not.

Here are the pics I could get tonight with a P&S of the cleaned up spindle's bearing surfaces. The first three are of the outer bearing portion and the fourth is of the inner bearing's surface. If these don't suffice I will whip out my DSLR tomorrow and work on a better shot. The backfocused shots are to try and show the relief view of the surface closer to the edges (where you are looking at the very edge of the spindle surface as it starts to go out of view). Not sure if they are useful or informative, but oh well.






IMO (but I'm a newb) it seems to be corrosion. The grease is a little greenish which makes me think water. I'm guessing here but since it is localized to the bottom part of the spindle on the outer bearings maybe my preload was ever so slightly off and my wheel was running a bit toe-out... letting enough moistish grease oxidize the spindle. On the other hand I could be totally wrong, I suppose at this point I just need to know if I'm screwed and replacing another spindle after 2 years of if this is simply something to check up on again at the next axle service.

I'm quite pleased with how this is otherwise going and enjoying it a bunch. Learning alot about the design of the driveline and how/where to look for problems arising and how to fix stuff "on the fly". A good project indeed

-----Nate

 

[Mr. Toad]

I think it looks like corrosion too. Especially in the pic which shows rust in the pits. It could have been a manufacturing flaw that was just waiting to rust when installed. The non-corroded parts of the spindle look very good. If it were wear, you would expect to see stripes all the way around the spindle (like a cooked crank or rod bearing). Edit maybe you have a little of that

FWIW, the bearings don't turn on the spindle (they have inner races which sit on the spindle), so I wouldn't worry about replacing that spindle unless the corrosion is severe AND it's in an area where a seal rides. Hit it with some emery cloth, grease it, and run it. And get your pre-load right.

I don't think the grease type is an issue.

 

[NaterGator]

Toad,

I'm thinking the same thing. H/E I just tore down the other side and the spindle has almost the exact same markings... though slightly less severe. Again this frustrates me because these are about 1.5-2 years old and the new style with the bearings for the axle shaft to ride on instead of races.

The only other problem I've found is the birfs seem massively dry to me. It's like the dealer just didn't pack enough grease into the case and bell... the inner knuckle was pretty darned full but the balls in the birf are super shiny and have little to no grease on them. Overall I'm really quite glad I'm doing this now, even if it is obscenely premature for the wheel bearings (they were inspected and repacked in March) and a bit early (about 10k miles) for the knuckles/birfs.


Off to the parts store to get solvent, more gloves, etc. Much work to do!

 

[Mr. Toad]

. . .
The only other problem I've found is the birfs seem massively dry to me. It's like the dealer just didn't pack enough grease into the case and bell... the inner knuckle was pretty darned full but the balls in the birf are super shiny and have little to no grease on them. Overall I'm really quite glad I'm doing this now, even if it is obscenely premature for the wheel bearings (they were inspected and repacked in March) and a bit early (about 10k miles) for the knuckles/birfs.


Off to the parts store to get solvent, more gloves, etc. Much work to do!

Glad you're doing it now too. The birf cavity (the cavity in the short axle shaft, not the hub) should be packed to overflowing with grease, and the open side of the joint should look pretty messy. Shiny bearings would piss me off if I had paid someone to do it, especially on an AWD vehicle.

Good luck

 

[Nailhead]

Your top picture in post #6 looks like fretting to me. I would say there was movement between the bearing race and the spindle. Either the nut was not properly torqued or the race was so worn it would spin on the spindle. Here's a definition of fretting corrosion.

Fretting corrosion refers to corrosion damage at the asperities of contact surfaces. This damage is induced under load and in the presence of repeated relative surface motion, as induced for example by vibration. Pits or grooves and oxide debris characterize this damage, typically found in machinery, bolted assemblies and ball or roller bearings. Contact surfaces exposed to vibration during transportation are exposed to the risk of fretting corrosion.
Damage can occur at the interface of two highly loaded surfaces which are not designed to move against each other. The most common type of fretting is caused by vibration. The protective film on the metal surfaces is removed by the rubbing action and exposes fresh, active metal to the corrosive action of the atmosphere.​

Fretting corrosion​

 

[NaterGator]

You must be in the field, sounds like that's exactly what it is.



Considering the look and feel of the rest of the spindle and the fact that the corrosion/pitting is hardly even detectable via a fingernail I think I'll lightly polish it and reassemble with the spindles.

I've decided to let my parts soak for a few days and just go to the beach in a different vehicle. I'll resume on Saturday night, when it will hopefully have stopped raining again.

Thanks all

 

['74 UA FJ]

Stop driving through mud/water so much.

And gloves, lol.

 

[NaterGator]

Stop driving through mud/water so much.

And gloves, lol.

Cleaning up is ludicrously easy when you just pull off a pair of nitrile gloves.

 

[Mr. Toad]

. . .

And gloves, lol.

Someday you'll have a girlfriend, and she'll totally dig you because you just fixed her axle, and she watched you do it, and maybe even bottle-fed you a beer at the halfway point, and the grime smudges on your forearms will even kind of turn her on, from a distance anyway, and she'll start giving you those looks and tilting her head and coyly smiling that special smile while you put the tools away after finishing the job. You, in turn will be too P-dazzled to do anything other than grin back, as if you have any control of this situation at all, and you'll drop things and stumble to pick them up and bump your head on your workbench while she giggles and shifts her weight so that her hips swing subliminally as you watch to see how she eats that banana that she so slowly peeled. You'll notice her looking around -- but only when she thinks you're not looking at her because when you are she's too busy flashing invitations to her womb -- for an impromptu nest and as you finally shark-walk over to land the catch she'll smell the 90-wt on your hands and tell you that she can't let you touch her because you smell like Yellowstone Park, and her stepdad did bad things to her there when she was nine, and even though she likes those things now the smell of sulfur brings back bad memories -- and she'll mumble something about having to talk to you about eating bean and cheese tacos before bed -- so you'll furiously scrub your hands off thinking you can still save the moment but when you come back she still smells it and you are left wishing you hadn't scrubbed all that lube off your hands.

Or you could wear gloves.

 

['74 UA FJ]

Someday you'll have a girlfriend, and she'll totally dig you because you just fixed her axle, and she watched you do it, and maybe even bottle-fed you a beer at the halfway point, and the grime smudges on your forearms will even kind of turn her on, from a distance anyway, and she'll start giving you those looks and tilting her head and coyly smiling that special smile while you put the tools away after finishing the job. You, in turn will be too P-dazzled to do anything other than grin back, as if you have any control of this situation at all, and you'll drop things and stumble to pick them up and bump your head on your workbench while she giggles and shifts her weight so that her hips swing subliminally as you watch to see how she eats that banana that she so slowly peeled. You'll notice her looking around -- but only when she thinks you're not looking at her because when you are she's too busy flashing invitations to her womb -- for an impromptu nest and as you finally shark-walk over to land the catch she'll smell the 90-wt on your hands and tell you that she can't let you touch her because you smell like Yellowstone Park, and her stepdad did bad things to her there when she was nine, and even though she likes those things now the smell of sulfur brings back bad memories -- and she'll mumble something about having to talk to you about eating bean and cheese tacos before bed -- so you'll furiously scrub your hands off thinking you can still save the moment but when you come back she still smells it and you are left wishing you hadn't scrubbed all that lube off your hands.

Or you could wear gloves.

lol. Nate doesn't have to worry about such things.

 

[Mr. Toad]

lol. Nate doesn't have to worry about such things.

Yeah, but he's someone's bear.

 

[NaterGator]

Is it safe to drive the truck for one day with one of the drive plate studs (some call them hub studs I guess... where the cone washers are on the face of the hub) out?

It seems like I should be able to replace it after the truck is buttoned up

Thoughts? Mr. T is closed today and I can't get a replacement until tomorrow.

 

[NaterGator]

Before I start buttoning all this back up I have a fairly pressing question (ok that was a terrible pun):

Seeing as though my spindles are new they are also the new design with the bearings instead of brass bushings for the axle shaft to ride on. In searching I haven't seen any discussion on the accepted method for cleaning said bearings: are we supposed to remove the pressed brass fitting and actually clean these by hand? Is a judicious use of brakeleen sufficient to remove the old grease and then repack?

Not sure the FSM has been updated to account for these bearings and I'm not sure how I should proceed. Still curious about driving a bit with 5/6 drive plate studs as well.

Thanks
-----Nate

 

[Elijah]

I'm not familiar with the new spindle bearing design, but you'll be okay driving around without 1 hub stud.

 

['74 UA FJ]

You'll be fine driving with one stud out. Just clean it with brake cleaner, rags, etc, until you think you've done a decent job. Don't over think things.