Birf grease leaking from Steering Knuckle Studs

[OGBeno]

If you're going to use the Valvoline (I did) then just buy the #986 full synthetic in a 1lb. tub. Also, I packed the trunnion (knuckle bearings) with the same moly grease I used for the birf.

They (the bearings) live in the same spot and need a grease capable of withstanding high pressures. The weight of the front end and all dynamic loading is directed to this spot.

Good luck.

Moly in the trunion bearings Flint?

As I've read and understood (and how I actually did it in Oct. 04), M1 goes into both the trunion and wheel bearings. Moly is only for the knuckle housing and inside of the birfield core itself.

That's my understanding (though as all of you know, I am wrong a lot of the time... ).


Tech Check, Tech Check; Aisle: Birfield


-onur
Akron, OH

 

[Biff]

Beno,

Should I just repack the steering knuckle, and ignore the one that is completely dry or do both knuckle and get it over with. Keep in mind this birf job was just done a few months ago.

 

[OGBeno]

Beno,

Should I just repack the steering knuckle, and ignore the one that is completely dry or do both knuckle and get it over with. Keep in mind this birf job was just done a few months ago.

I'd check the bolts underneath first to make sure that the dry knuckle will not end up looking like the dirty, leaky one. Torque them up too.

I'd just work on the one that has issues...open it up, clean, repack, and replace seals/gaskets if needed (I think you might), and re assemble making sure everything is tight.

Again, I am no expert considering I've done it only once before. (Never thought I'd be getting questions.... )

I think others on the board will have better opinions (IDoug, Jim, NorCal Doug, CDan, CDrew, Rookie2, etc.) than myself.

But that's my .0000000000000000000002.
-o-

 

[Biff]

I'd check the bolts underneath first to make sure that the dry knuckle will not end up looking like the dirty, leaky one. Torque them up too.

I'd just work on the one that has issues...open it up, clean, repack, and replace seals/gaskets if needed (I think you might), and re assemble making sure everything is tight.

Again, I am no expert considering I've done it only once before. (Never thought I'd be getting questions.... )

I think others on the board will have better opinions (IDoug, Jim, NorCal Doug, CDan, CDrew, Rookie2, etc.) than myself.

But that's my .0000000000000000000002.
-o-

Thats what I figured, I'm just going to work on this one and retorque all the steering knuckle bolts. Hopefully its only the inner axle seal.

 

[flintknapper]

Moly in the trunion bearings Flint?

As I've read and understood (and how I actually did it in Oct. 04), M1 goes into both the trunion and wheel bearings. Moly is only for the knuckle housing and inside of the birfield core itself.

That's my understanding (though as all of you know, I am wrong a lot of the time... ).


Tech Check, Tech Check; Aisle: Birfield


-onur
Akron, OH

Yup, all I've done here is use a higher grade grease than called for in the FSM.

FSM calls for a MP (multi-purpose) wheel bearing grease for the wheel bearings, a lithium base grease for the trunion bearings, and moly fortified grease for the birfs.

I used the same moly grease for the trunion (knuckle) bearings because it provides greater film strength than lithium alone. I did not use a grease that is incorrect for the application....only a grease that is "better" than what is called for.

Additionally, if you look at where the trunion bearings reside, (inside the birf. housing)... you'll notice that the bottom of the bearing and the "kingpin" are exposed to same grease you packed the birfs. with....should any of it migrate.

The wheel bearings could be packed with a MP grease as is called for in the FSM....but like you, I chose to go synthetic there as well.

When we say "moly" grease we're not talking about pure Molybdenum Disulfide, but a mixture of some percentage (fortified). They do need to be rated at the industry standard NLGI #2.

 

[IdahoDoug]

Biff,

I wouldn't jump all over this unless you simply have the time and it's no big deal. Personally, I'd lay a few old rags under those four bolts, wipe off all the excess grease you can see squirted out there, then liberally spray the entire area with brake cleaner to get ALL the grease/oil off the bottom surfaces (don't get any on the birfield ball or soak the felt/rubber seal).

Then you can simply watch this area over the next few weeks to confirm if what I'm about to give as my prognosis is correct or not.

I think you simply had some M1 grease on the bottom of the knuckle housing when you bolted the steering arms/bottom cap on, and also I see some around the bolts as well. Naturally, it squeezed out like we see it - the red stuff that's been forced when the surfaces came together. Then, some of the oil did indeed separate out of the grease and run down and wet things a bit. I spoke with the Mobil technicians about the tendancy to separate and the short answer is that "it's oversaturated with synthetic oil to maximize lube properties and yes it separates a bit because of this". No big deal, and that has been my experience with the M1 in bearings also.

I think if you clean the area up, you'll not see a drop come out over the next weeks and months and it will confirm my prognosis. I really do - unless by coincidence you actually are positive there was absolutely no grease squeezed out there when you reassembled.

However, I'd check the torque on the bolts of both sides just because I'm a safety nut.

Finally, I agree the M1 is not the best choice for the birfs but honestly I think the M1 is seriously good stuff and you will not have a problem at all since it's top shelf.

DougM

 

[Rookie2]

Thats what I figured, I'm just going to work on this one and retorque all the steering knuckle bolts. Hopefully its only the inner axle seal.

I honestly don't feel like what your seeing there is a failed inner axle seal, but rather separation of the synthetic grease. It's almost like once the grease separates, the highly liquid portion of that is like penetrating oil and can seep past any little seam available. Now, loosened knuckle studs, is also possible and you should definitely double check that. I would be more concerned about not having Moly fortified grease in the knuckle as specified in the FSM. Seems like I recall reading there is a specific reason for having the Molybedinum Desulfide additive present for this application, and the lack thereof could result in wear inside the birf. over time. Frankly, I'm not educated enough about the reasons, but personally wouldn't buck the FSM on this one. Sure.. while you're in there, replace the axle seal. No reason to do all that work, and not have all your bases covered. Talk to C'Dan about it when he gets back from vacation.


Rookie2

 

[Curran]

Biff,

I wouldn't jump all over this unless...

DougM

Doug, I'm going to respectfully disagree with you on this one 'cause I think that it is a real safety issue. Regardless of the grease's tendency to separate, it should not migrate down the studs and out the cone washers if the studs are properly tightened. Amsoil Moly separates similarly and with all the maintenance freaks on this board packing their birfs and knuckles with either Mobil 1 or Amsoil, this wouldn't be an unusual sight if it were par for the course.

My PS side steering arm looked like this a couple of months after I repacked the birfs. And I did pretty much what you suggest above. I cleaned the area real well with a degreaser; retightened the nuts on the steering arms and waited for a bigger sign that something was goofed up.

Additionally, I think that the interface between the steering arm and the knuckle needs to be free of grease 'cause i have a hard time believing that those studs are sized to operate solely on shear strength.

One could argue that my failure came at the end of a hard day wheeling but C-Dan has seen the same failure on a mom-mobile that never ventured off pavement that resulted in the whole knuckle separating from the axle housing. The woman driving was OK, but the truck was darn near totaled

Biff,
Without taking everything apart remove the nuts and cone washers on the inner most studs (It’s much harder to get to the outer studs with the dust shield in place). Then, try to see if you can turn the studs with a pair of pliers or vice-grips. If they don't turn easy, then I'll get off my soapbox and concede to Doug's recommendation. But if you can spin the studs, I'd get on it sooner rather than later.

 

[Biff]

Well I tripple check all the steering knuckle studs and they are super tight. I notice a red liquid appearing now. Could it be the red grease liquifying/breaking down, what do you guys think?

I've tried wiping the area down several times and the grease always comes seeping out.

 

[IdahoDoug]

Biff,

That's new news that you've already done what I suggested by wiping it down and more is coming out. I have made the observation on my knuckle repacks that the steering arm CAN be forced to 'jam' crooked on the bottom of the knuckle if the 4 stud nuts are not carefully tightened a bit at a time. You can definitely end up with the arm crooked and go to full torque without it straighening itself out and ending up square. I believe this may be what's going on here and it will take you only a few minutes to do. You'll know that this is what happened if when you loosen the 4 nuts it is a lot of pounding to get the arm to come off, or if it comes loose with a bang. Since you just reinstalled it, it should come off easily unless you've got it cocked slightly.

With that new info, I'd loosen the 4 nuts and pound the arm loose, then retighten it carefully in a cross/circular pattern like you would do with a head, or wheel lugs. And yes, the oil coming out of the M1 grease is red, but it will turn brown when running down something like that dust shield.

 

[Kalawang]

Victor--

The birf should be repacked with Moly grease (gray, dark peanut-buttery consistency stuff)....not the M1 which is red and is for the trunion and wheel bearings...

Cool?
-o-

I might be in trouble. The stuff I used was a beautiful jewel blue.


Kalawang