80 series axles what could I have possibly done wrong? (1 Viewer)

[84lumberman]

Okay, I have no idea why this would look like this. I replaced the original axles with RCV birds and new hardware and I followed everything torqued down to spec from the factory and I do not understand why it looks like it's leaking again. This should not happen as far as I understand and I don't know what could be causing this. Does anyone have any idea on what to look at? I have a full shop with lifts and tools and equipment so I don't have any limitation on how to access anything. I just need to know what to tear apart to check on this because it seems like I'm going to have to remove everything again and redo it all but just using the same parts

 

[77mustard40]

How many miles on the knuckle job and what seals did you use?

 

[Broski]

Did you use OEM seals ?
It's possible that the axle vent is clogged, this is common
Some will drill it out to a larger hole when they it out including me.

 

[baldilocks]

I’ve had three separate issues with RCV shafts not being machined properly. The surface where the inner oil seal rides on the shaft might not be exactly the correct size or location. A tiny scratch on that surface and there will be a leak (first hand experience here).

Another mistake I’ve made is deflecting the oil seal too much as I pass the shaft though It and that tiny spring that’s on the back side of the seal ends up down in the bottom of the differential where it’s not doing it’s intended job anymore.

Did you install that shim under knuckle trunnion pin? If I remember correctly there is usually one thin shim between the knuckle and the lower pin.

No matter the cause you are going to have to disassemble to inspect and install new oil seals.

 

[mudgudgeon]

Take the square plug out of the top of the knuckle, dip a zip tie in and see if you have grease or birf soup in the knuckle.

Doesn't look terrible, not awesome, but not terrible.
The knuckles always weep a bit.
Oil separates out of the grease and weeps past the bolts

 

[Broski]

Take the square plug out of the top of the knuckle, dip a zip tie in and see if you have grease or birf soup in the knuckle.

Doesn't look terrible, not awesome, but not terrible.
The knuckles always weep a bit.
Oil separates out of the grease and weeps past the bolts

This is true.
But gear oil is not supposed to be in the knuckles in the first place.
If there’s gear oil in there there’s another issue at play.

 

[mudgudgeon]

This is true.
But gear oil is not supposed to be in the knuckles in the first place.
If there’s gear oil in there there’s another issue at play.

Grease contains oils.
IME the oils separate out over time and heat cycles.
I've had knuckles weep oil at the bottom, without having birf soup.

 

[Rusty Marlin]

Grease contains oils.
IME the oils separate out over time and heat cycles.
I've had knuckles weep oil at the bottom, without having birf soup.

Same here. In fact mine look like that all the time.

 

[azusa]

I know Valvoline vv985 or vv986 full synthetic grease and I also believe synpower grease, whenever I have used those greases, oil from the grease continuously bleeds off/separates. What grease did you use for the birfs?

 

[Broski]

IMO it looks like more then a weep.
Here's mine, it's been 10 months since a full service on the front axle. To be fair I don't DD it but it see's a lot of hard off road miles. and some street miles

What I have been using

 

[Kernal]

IME the Valvoline Palladium doesn't separate very much of the lube oil held in the grease, Mobil 1 on the other hand does.

As mentioned a few times above, best guess is there's a problem with the OP's seals or shaft surfaces.

FWIW: my method to eliminate the possibility of oil from the grease working it's way past the threads of the studs is to seal the knuckle studs when installing ie: super clean all threads first (stud and hole), then apply blue thread locker on the stud and hole threads (both because it's not a blind hole). Then install the studs tightly, ensure the top of the stud holes (inside the knuckle) are dry (Q-tip to absorb any excess thread locker), then add a dab of FIPG (brand your choice) down into the top of the stud holes from inside the (cleaned) knuckle. I've never seen gear oil dripping off my knuckle nuts/studs after that process.

Edit: to be clear, for either of those tips to work, the metal has to be absolutely squeaky clean to start using a strong detergent (Purple Power etc) and Acetone. There needs to be zero oil, zero grease or grime on any components which means the knuckle must be taken off the vehicle, thread cleaning tap (not cutting) run down the holes repeatedly, blow out the holes and cleaning tap with Acetone (Green can CRC brake cleaner), cleaned more with strong detergent cleaner with final rinse using Acetone anywhere the thread locker/sealer or FIPG will go. A quick swipe with a dirty rag won't be enough.

Saves a little time to start with new (clean) OEM knuckle studs which come with a little thread locker/sealer on a couple of threads (I still add more blue loctite). The new studs come with a hexalobular (E-Torx) head which makes it easier to install. FWIW

 

[CrabCake]

Interesting that it's almost identical for each side....will be interested to hear a few more details such as mileage on job, grease, is it actually birf soup, etc. From my recent experience, if you see oil dripping off of the nuts like that, it's going to be gear oil infiltration...pointing to oil seals as they are the only thing really separating the gear oil and birf grease.

 

[Broski]

FWIW: my method to eliminate the possibility of oil from the grease working it's way past the threads of the studs is to seal the knuckle studs when installing ie: super clean all threads first (stud and hole), then apply blue thread locker on the stud and hole threads (both because it's not a blind hole). Then install the studs tightly, ensure the top of the stud holes (inside the knuckle) are dry (Q-tip to absorb any excess thread locker), then add a dab of FIPG (brand your choice) down into the top of the stud holes from inside the (cleaned) knuckle. I've never seen gear oil dripping off my knuckle nuts/studs after that process.

I like this idea.
And what I like about the community, I'm always learning !

 

[GeoRoss]

Grease contains oils.
IME the oils separate out over time and heat cycles.
I've had knuckles weep oil at the bottom, without having birf soup.

Same here. In fact mine look like that all the time.

Same here. It mildly bugs me and I’m sure it is just separating and seeping down the studs. I’ll try the @Kernal rtv trick the next time I do the front axle.

 

[Broski]

Same here. It mildly bugs me and I’m sure it is just separating and seeping down the studs. I’ll try the @Kernal rtv trick the next time I do the front axle.

Same here. In fact mine look like that all the time.

What Grease are you all using ?

 

[GeoRoss]

What Grease are you all using ?

 

[Broski]

I’m thinking that the synthetic oil contributes to the issue. Be interesting to know what the original poster is running.
I’m to cheep and in there to much to run synthetic.

 

[Rusty Marlin]

Valvoline or STP EP Moly grease. What ever is at AutoZone.

 

[80t0ylc]

I’m thinking that the synthetic oil contributes to the issue. Be interesting to know what the original poster is running.
I’m to cheep and in there to much to run synthetic.

You may be right, my Amsoil synthetic grease has always had a separation issue, but still maintains a superior lubricating quality in temperature extremes. TG polyurethane knuckleball seals have really helped leakage. But after six years and 25,000 miles, the knuckle nuts are just starting to show some seepage.