Ah, purple Amsoil balls.....

[IdahoDoug]

Yep, just finished the birf repack on the new 97. I was surprised how nice the birf grease was - kinda sloppy and whipped looking, but not much oil contamination from the axle seals compared to my 93 at around 90k. Both axle seals were in very nice shape, owing to the fact that I could barely see a wear pattern on them. Both were worn *faintly* at the 12 O'clock position, but these axles were clearly running almost in the center of the seals - the key to long birfield maintenance cycles.

Also found an inner wheel bearing showing some distress, and its race had clearly been hammered in three spots. Strange wear pattern that looked like only half the race and bearings were touching each other. Wonder if this was the slight wander the truck had? I'll find out tomorrow on the test drive.

The knuckle bearings were fine, but I replaced them anyhow so I don't have to open things up for another 100,000 or so.

This subject has been beaten to death, but I have a couple comments.

First, John Davis mentioned in his rebuild that the ABS sensor O rings were looking kinda sad. Mine were too, so if anyone can find a source for the correct size of these it would be great. Don't forget to liberally grease these sensors before reinstalling them so the O rings aren't torn.

Second, if you're going to wheel your rig in wet conditions, consider liberally working fresh grease into the felt seal before buttoning it up. They'll get a little saturated, but it may take months for them to be waterproof.

Third, consider greasing the entire inner axle before inserting it to prevent damage to the new axle seal. Yes, you'll have a half teaspoon of contamination in the front diff, but with the high front diff oil volume it will hardly be noted.

Fourth, the question if oil pumped in the square plug gets to the birf has been answered - yes it will! I put a half tube of fresh grease in there a few thousand miles ago on someone's suggestion (anyone remember who - Rich?) and it had indeed been churned into the birf. Not sure how much of this successful churn was because the existing grease had been thinned and undoubtedly allowed more turbulence in the knuckle than fresher uncontaminated grease might have. So, an interesting find.

So, at 138,000 everything looked pretty solid in there except for a bearing.

While it was apart, I sanded the front rotors to take the gloss off. I also elevated the front diff vent. Anyone who's interested in prolonging their birf health has got to do this simple mod. For fun, I timed this and it took me 3 minutes, including installing 2 zip ties with the wheel off. Drop the new hose down from the engine bay, lean in the wheel well with pliers and pull the spring clamp off the existing hose after pulling it off the nipple. New hose attached. 1 zip tie to the old hose. Stand up and cut the hose up in the engine bay to the preferred length. 1 zip tie in the engine bay next to battery box. Done. I'll get a cheap fuel filter on it later to prevent bugs, dirt from getting in.

So, after a quick spin around the block, the 97 joins the 93 in having birf balls covered in purple Amsoil...

DougM

 

[Rich]

...
Fourth, the question if oil pumped in the square plug gets to the birf has been answered - yes it will! I put a half tube of fresh grease in there a few thousand miles ago on someone's suggestion (anyone remember who - Rich?) and it had indeed been churned into the birf.
...

Credit accepted. Glad you were willing and able to do the test.

 

[powderpig]

While the grease will get into the main area of the housing, it will mix with it, it will not lube the inside of the birfield. If you think grease will get inside the birf you are not thinking real well. Unless the grease is so thin that it will some how flow past the balls and all the tight wear area. This is why some auzzie company has taken to drilling and putting a zert fitting on the end of the birf (mostly for the mining companys). This truly will lube the birf. I do think having more grease inserted into the knuckle chamber will help the loss of grease from the birf(slow down the movement of grease). This is best done with the wheel turned out on the side you are working on, thus putting the hole over the knuckle chamber, thus allowing the grease to get into the knuckle champber easier . later powderpig

 

[IdahoDoug]

Powder,

I've felt as you posted for years, having done a repack years back and studying the design while it was apart. I also concluded that it would not get into the birfield joint itself. However, my observation yesterday changed my view. There was no question the fresh grease I put in mixed into the grease in the birfield joint itself as I used a different color and this color was present uniformly in the birfield itself. I suspect I underestimated the amount of turbulence that occurs in the birfield and the amount of grease exchange this would cause between the grease in the birfield and the greater steering knuckle.

So, even though you think I am not "thinking well", I assure you I was as surprised as anybody - which a search on my past posts on this topic will confirm.

DougM

 

[powderpig]

So you say that the grease was the same color mixed both inside the birf anf the outside. This would be a real suprise. I think this would happen in the tight cofines of a car cv with the rubber boot. but in the knuckle of the 80 with a few place (and space)for the grease to go and the spinnig of the birf that this just does not seem possable. But stranger stuff has happened in the world we live in. Great find. Later Powderpig

 

[e9999]

good news indeed.
However, I never got why everybody seemed so bent on declaring that there was no way for the grease to get in there. I mean if you fill most of the knuckle up with grease and the birf is spinning at high rpms, there is bound to be some migration...

 

[IdahoDoug]

Easy E - I was the staunchest supporter of the "no mix" position. At the moment I'm dealing with this #$%@ sword I seem to have fallen upon and you're twising it <grin>.

Yes, there was uniform mixing. Only places the fresh grease was unmixed were right at the fill plug depression, and a couple creases high up in the steering knuckle housing outside of the birf chamber. It was interesting to note that some of the fresh stuff also goes directly to and out the sweep seals (triple seals) which is also good. This means if your birf outer balls are dry and you're planning to go wheeling somewhere wet it would be an extremely good idea to pump some in to rewet the seals and prevent dirt/water ingress. Within a few days of pumping the fresh grease in, the balls began to get the proper film of grease though it was spotty at first due to stiff felt. From the inside, I could see that fresh grease had gone directly to this area over the top of the birf chamber since that's where the square plug is. I'd turn the front wheels inward to get grease directly to these sweep seals, and outward as noted by Powder to focus on the birf chamber's open side.

I also forgot to mention that these outer balls had been run dry for quite some time - perfectly dry. Yet the rubber lip was not noticeably rounded where its square edge drags on the ball, so still sealing well. However, a rust line had formed in several places where the truck must have been parked after driving in the wet. What happens is the felt seal is no longer saturated with grease, so it soaks up road water and sits wet. I used a razor blade and abrasive pad to remove these back down to smooth steel.

DougM

 

[T Y L E R]

Ohhhhhhhhh .. ok. Sorry


I figured with the family gone you were commenting on another set of purple balls ..



TY - all about tech !

PS: Aww the embarrassment ... look away .. look away , nothing to see here

 

[Rookie2]

Credit accepted. Glad you were willing and able to do the test.

I'll take that credit. See post #10 and #12.

https://forum.ih8mud.com/showthread.php?t=47146&highlight=grease+die

I actually presented this theory of circulation twice and don't recall anybody falling on this side of the fence of even plausability except maybe Raven.

Thanks Doug for doing the test. I was almost prepared to do another teardown to prove it.


Rookie2

 

[e9999]

this is good work! and very useful. Gives me some more peace of mind and more excuses to delay doing the Birf job!
Glad to see that the Toy engineers did not (completely?) fumble this one!

 

[IdahoDoug]

I also came up with a foolproof way to clean the birf without disasassembly.

Get 4 cans of brake cleaner for each side. Once they're cleaned and wiped as much as possible with rags, stand them with the opening facing down in a bucket or wherever you want the grundge to drip. Put the straw tube on the cleaner and jam it all the way into the joint and start spraying. Keep turning the birf and inserting the straw past each ball in turn. A single lap around will exhaust most of the first can. Then flip the birf up side down and spray brake cleaner into it so you're filling it like a cup until you can barely see the fluid level. Now run the upper section of the axle (the inner axle) around in circles which mixes and dissolves the grease. This is harder with the left side as the inner axle's heavy (yeah, I know - whimper). Then turn it over and pour the grundge into the bucket. Repeat this until the cleaner comes out clear. Use nitrile gloves to keep that nasty cleaner off yourself. Then prop the axle in a corner with the opening down to continue draining any excess cleaner.

Before installing mine an hour later, I used a blow drier to ensure all solvent had dried, and the warm birf seemed to help me get the fresh grease packed down in with a thin spatula (glad my wife's out of town - hopefully she won't notice it missing).

DougM

 

[Beast II]

I cleaned the birfs that exact same way and clamped them in a vice with the opening side down overnight to ensure that all of the brake cleaner was gone. Worked like a charm.

Now if only I'd used the appropriate grease in the hubs (which I just changed back to Mobil 1 Synthetic) and if I'd known that the bearing races were not part of the packaging, I wouldn't have had to do the birf twice and the hubs three times.

 

[Rich]

...I'll take that credit. See post #10 and #12.

https://forum.ih8mud.com/showthread.php?t=47146&highlight=grease+die
...
Rookie2

Rookie, maybe this will refresh your recollection.

Ok, 5K miles before somebody does a repack they need to fill the knuckles through the plug with some bright red or bright blue grease. Then, when the birfilelds are pulled 5K miles later you will see to what extent the grease migrates throughout the knuckle.

I'd think once warm the grease would migrate around quite a bit and end up flowing towards the bottom of the knuckle.

https://forum.ih8mud.com/showthread.php?t=35084

 

[IdahoDoug]

You 'da man - now I remember. I think I put only a few thousand on it, but suspect the mixing occurred pretty fast - like the first freeway drive where things get high RPMs and heated well.

DougM