How Low Should Steering Knuckle Grease Get?

[turbocruiser]

Hi all, I was repacking my steering knuckles tonight and thought that about six squirts of grease was what was recommended (based on search) but with six squirts, I could see that the grease was barely beyond the half way up point of the knuckle. How much should I squirt in there? Should I really do what the FSM states and repack the whole knuckle? Between the search and the FSM I am confused; I do not want to overpack the thing and blow out the felt seals. I also do not want to let them get dry from half way up. Thanks.

 

[Riley]

I'd consult the birf repack tech notes. I think they say from about 1/2 full to 2/3 full. I wouldn't measure in squirts but in how full the knuckle is.

People usually talk in squirts in regards to doing regular PM in which they squirt into the knuckle from the plug hole. This is done to compensate for the grease lost through the seals over time.

Riley

 

[IdahoDoug]

Turbo,

Clarify what you're doing here. Are your knuckles disassembled and you're repacking them, or are you actually merely putting grease into the removable square plug atop the knuckle?

DougM

 

[turbocruiser]

I am just putting the proper grease in through the square plug at the top of the steering knuckle. This is the first time I have had the plugs out too so i want to fill up the knuckle but not overfill it. When I spotted a stong light through the threaded area for the plug, I could see that the grease was only up to the half way up point of the knuckle so I wanted to add much more than the six squirts that was the consensus from the search. It seems so simple but I want to do it right. The FSM states to 'repack' the entire knuckle but even after twenty squirts with the grease gun, there is still room for more grease. Thanks for putting up with this simple post, I appreciate the advice.

 

[ryanjl]

Putting grease in the hole you are using doesn't really accomplish much. Complete knuckle dissasembly is the only real way to get the grease where it needs to go. The knuckle should only be about 2/3 full of grease when done; overfilling can blow your seals out.

 

[IdahoDoug]

I see you've got some extra ponies on your 80, and a lift and other goodies that indicate it may see some offroad work. I mention this from the perspective that these indicate a bit more aggressive maintenance schedule from a mall cruiser.

If you've never been inside the steering knuckles, you may not have the internals framed in your mind. So I'll attempt to do so and you can make the call. The actual birfield resides in a cave that is open into the steering knuckle housing, which could be regarded as a second larger cave. The square plug is in the ceiling of the larger cave and putting grease into it doesn't really get any into the smaller cave to speak of. It would kind of merely be like rain falling across the opening of the smaller cave the birfield lives in. But that grease in the steering knuckle housing has a purpose, which is to provide grease to constantly weep out the felt/metal/rubber seal (known as a 'sweep seal') and keep it lubed for a good seal. The weeping acts like tears in the eye, which also constantly weep out of the lids and similarly carry debris and dust away from the seal edges.

To me, there is really no danger in overfilling the steering knuckle housing. Doing so merely accelerates the rate at which it goes out the sweep seal. There is really no way to create excess internal pressure in this housing, as the seals are not pressure tight. So, your call.

Putting a few squirts in whenever the shafts are lubed is simply a way of maintaining a reasonable level in the housing between complete repackings. If you're between halfway full and 3/4 full I think you've done a proper job of this task.

My opening comment is just to alert you, in the absence of any info when a proper repack was done, that you might consider more attention to the birf health as part of your task in maintaining a more powerful engine'd rig that's used off road.

HTH,

DougM

 

[Big_Moose]

I agree with Doug, and the other reason to maintain close to full levels of grease in the knuckle cavity is to lubricate the knuckle (kingpin) bearings, axle seal, and spindle bushing (or roller bearing).

Joe

 

[turbocruiser]

[quote author=IdahoDoug link=board=2;threadid=10876;start=msg97749#msg97749 date=1075702513]
I see you've got some extra ponies on your 80, and a lift and other goodies that indicate it may see some offroad work. I mention this from the perspective that these indicate a bit more aggressive maintenance schedule from a mall cruiser.

If you've never been inside the steering knuckles, you may not have the internals framed in your mind. So I'll attempt to do so and you can make the call. The actual birfield resides in a cave that is open into the steering knuckle housing, which could be regarded as a second larger cave. The square plug is in the ceiling of the larger cave and putting grease into it doesn't really get any into the smaller cave to speak of. It would kind of merely be like rain falling across the opening of the smaller cave the birfield lives in. But that grease in the steering knuckle housing has a purpose, which is to provide grease to constantly weep out the felt/metal/rubber seal (known as a 'sweep seal') and keep it lubed for a good seal. The weeping acts like tears in the eye, which also constantly weep out of the lids and similarly carry debris and dust away from the seal edges.

To me, there is really no danger in overfilling the steering knuckle housing. Doing so merely accelerates the rate at which it goes out the sweep seal. There is really no way to create excess internal pressure in this housing, as the seals are not pressure tight. So, your call.

Putting a few squirts in whenever the shafts are lubed is simply a way of maintaining a reasonable level in the housing between complete repackings. If you're between halfway full and 3/4 full I think you've done a proper job of this task.

My opening comment is just to alert you, in the absence of any info when a proper repack was done, that you might consider more attention to the birf health as part of your task in maintaining a more powerful engine'd rig that's used off road.

HTH,

DougM
[/quote]


Wow, Doug, thanks so much for the post, that was awesome, and, that was appreciated. As far as the offroad work this vehicle has seen, most of it (mild to mildly moderate) has happened since I got it about two months ago. The PO rarely wheeled it and when it was wheeled, it was wheeled to simple places to go to campsites and such. Actually the PO regretted the fact that it was rarely wheeled with him; he put so much thought and so much time into modifying this vehicle but because of a busy personal and professional life, he was not able to work it like it could be worked. Slee Offroad did both the front and rear axle service completely about ten thousand miles ago so I am sure that the 'smaller cave' you described so well was adequately full of grease, I just dont think that the larger cave was replinished since Slee did it. Thanks again so much for the advice. I had searched the subject but was somewhat confused between the search and the FSM. Your description of the internals was easy to read and easy to understand. Thanks again, i really appreciate it. Happy wheeling!

 

[Pitbull]

I asked this same question about 6 years ago on 80's cool and Norm from OZ (who is considered the guru of 80's) stated the 6 squirt process at every oil and filter change interval. I had filled mine clear up at the time and was affraid that I might of done the wrong thing. He stated that it would not cause any damage but just work its way out. He was right and I have used the 6 squirts for the past 6 years and no problems.

 

[Wayne]

This is a great thread....... . Very informative.

Wayne S

 

[landtoy80]

On the LCML, they don't beleave in adding grease in the fill hole.
At least that how it was when I had the 60

 

[turbocruiser]

[quote author=landtoy80 link=board=2;threadid=10876;start=msg98227#msg98227 date=1075776107]
On the LCML, they don't beleave in adding grease in the fill hole.
At least that how it was when I had the 60
[/quote]

Why? Thanks.

 

[landtoy80]

THey said it does nothing when you add grease in the fill hole.
I said,Why would Toyota put it in the 60, 80 (and I bet its in the 40 among others) and have it serve no purpose?

 

[turbocruiser]

[quote author=landtoy80 link=board=2;threadid=10876;start=msg98263#msg98263 date=1075777941]
THey said it does nothing when you add grease in the fill hole.
I said,Why would Toyota put it in the 60, 80 (and I bet its in the 40 among others) and have it serve no purpose?
[/quote]


Amen to that; to go through the trouble to create two chambers, use seals that are designed to weep some grease out (so that lots of dirt cannot come in), then drill and tap an area for the plug...it goes on and on, not likely an accident of engineering. Also, I would think that if those felts are bone dry and dirty, they could create a helluva abrasive effect. Anyway, Mr. T tells me to replish so I replish, my knuckles runeth over!!! Thanks for the advice, it is appreciated.

 

[ryanjl]

[quote author=turbocruiser link=board=2;threadid=10876;start=msg98279#msg98279 date=1075779907]
Amen to that; to go through the trouble to create two chambers, use seals that are designed to weep some grease out (so that lots of dirt cannot come in), then drill and tap an area for the plug...it goes on and on, not likely an accident of engineering. Also, I would think that if those felts are bone dry and dirty, they could create a helluva abrasive effect. Anyway, Mr. T tells me to replish so I replish, my knuckles runeth over!!! Thanks for the advice, it is appreciated.
[/quote]

When you ever have one apart you'll know that filling the hole doesn't get grease into the bearings in the birfield, where it's needed most. Here in this picture you see the birfield and the fill plug:

You can see that by putting grease in the fill plug (top right of knuckle), you'll never get grease inside the birfield (bell shaped thing opening towards the center of the vehicle located inside the knuckle). The ring with teeth you see is obstructing your view of most of the birf. That's the ABS ring, here's one without it:

Like Doug said, putting grease in the hole is usefull to keep the wiper seals lubricated. Another use? If your grease begins to go south, normally from water and/or differential oil contamination, it will tend to level out more in the knuckle. The "grease fill plug" in this case can serve as a hole to insert a clean stick or something that will let you look at the condition of the grease in the knuckle once the stick is removed. Kinda like the dipstick is used to check your engine oil.

That said, if Slee just did the job 10,000 miles ago and you havn't seen any grease leaking out through the wiper seals, I don't thing you really have anything to worry about.

I think that the best pictures to get an idea of the overall order of things in there are found on George's site:
http://www.geocities.com/george_tlc/birfield.html

Norm's write-up is good too:
http://www.safari4x4.com.au/80scool/tech/birfield_repack/repack.html

 

[cruiserdan]

OK, I'm going to toss a grease gun in the works :

Agreed, filling the knuckle by using the hole in the top does not directly get grease into the joint. That being said, think about this:

If you have grease in the joint and grease in the knuckle there is equilibrium. the grease in the knuckle retains the grease in the joint. As the grease leaves the knuckle it opens up space that will allow the grease to leave the joint. If the knuckle cavity is kept supplied with grease the grease within the joint has no place to escape to.


D-

 

[Pitbull]

[quote author=cruiserdan link=board=2;threadid=10876;start=msg98436#msg98436 date=1075821630]

OK, I'm going to toss a grease gun in the works :

Agreed, filling the knuckle by using the hole in the top does not directly get grease into the joint. That being said, think about this:

If you have grease in the joint and grease in the knuckle there is equilibrium. the grease in the knuckle retains the grease in the joint. As the grease leaves the knuckle it opens up space that will allow the grease to leave the joint. If the knuckle cavity is kept supplied with grease the grease within the joint has no place to escape to.


D-
[/quote]

Dan that makes sense. I love logic.

 

[Beowulf]

Christo posted a picture of an 80 front diff where the owner had aggressively used the "square plug" approach to birfield maintenance. It was not a pretty sight.

Can anyone (Christo? Robbie?) repost that picture in this thread. I've looked several times and cannot find it.

-B-

 

[IdahoDoug]

Dan's got an excellent point. The volume of grease outside the inner cave will help prevent grease flow out of the inner cave.

The second picture above is a good illustration to use in understanding the "inner cave/outer cave" layout. The grease gun is putting grease in the inner cave, whose edge is the silver edge just to the right of the grease gun. Look beyond this edge and you'll see the rough inner surface of the outer cave, which also has a shadow on it. That's where the grease inserted via the square plug goes, and you can plainly see that it will not get through the slot where the grease gun is working. In point of fact, the grease gun here is merely putting a top layer on after the regreased birf was inserted. Much deeper into the inner cave are the bearing surfaces of the birf that actually need fresh grease.

DougM

 

[malcolm]

I bought a 95 a few months ago and got enthusiastic about greasing the knuckles. I thought it was just a big ball and socket joint and if I greased it right grease should come out of the joint. I got the proper fittings and pumped a tube into the knuckle. I can remember lying under the truck with that uh-oh type feeling when no grease came out (where'd it go?). I researched this site and got educated on birfs and did the repack. What was said about the inner and outer cavities is true, and in fact is kind of a bad design. In the inner cavity contains a bushing that holds the birf in place and it needs to be greased. By the way, the tube o' grease went into the differential and when I drained it came out like [you guessed it].

It turned out that the side that got the tube was very well lubed, even inside the birfield. The other side had a leak past the oil seal and the oil washed out the grease and the bushing got dry and started sticking to the shaft. I had to replace the spindle assembly. Oil leakage is a bad sign in addition to clicking, grinding, or any other percussion type sounds.
Good luck.