adding/inspecting birf grease through abs sensor hole? (1 Viewer)

[semlin]

this just occurred to me while reading Curran's scary post about the studs backing out of his knuckle arm and letting grease out. Why can't you service the birfs by popping the abs sensor off the top of the housing and adding fresh grease right into the knuckle housing where it will do lots of good? I expect it will be tricky to get the sensor off without pulling the hub and rotor off but not impossible and even if you do have to pull the rotor that is still way less work than a full repack. Also, wouldn't this enable you to sample the condition of the grease inside your knuckle housing if you suspected birf soup?

 

[Rookie2]

Semlin:

I'm not sure I see the advantage of adding grease through the ABS sensor hole instead of the plug hole. They both would be filling the knuckle housing cavity. I guess the ABS hole is a little bigger and if you remove the wheel to get at it, may give a better vantage point of inspecting the grease.

Although the ABS sensor seemed to come out easy enough, messing with it seems to just create one more opportunity to screw it up.

Just my .02.


Rookie2

 

[TLCgrappler]

Having just been in there, but not having the Cruiser in front of me at this moment, I think the hole for the ABS sensor is all of about 3 inches from the normal knuckle grease plug hole. To my eye, putting grease in one would be roughly the same as putting it in the other, except that the toothed wheel on the birf is just underneath the sensor so it might be tough to get the grease gun in there.

Seems like it would be better to just use the grease plug hole and leave the ABS teeth alone.

 

[semlin]

if you can see the abs ring teeth of the birf does that not mean you can get grease through that hole into the inner knuckle housing?

 

[IdahoDoug]

IIRC from my repack the ABS ring is well outboard of the chamber the birf itself rides in. I believe it's out on the outer axle stub. I agree with the comment that it's very close in function to accessing via the factory plug - good for filling the knuckle chamber but not effective for getting fresh grease into the birf.

DougM

 

[RavenTai]

The abs ring is where the bell meets the stub shaft, this would be the outer portion of the knuckle chamber same as the plug,

Some say putting grease here does not do much good for getting grease where we really want it, the inner knuckle chamber,

As far as I can figure this is probably very accurate when gear oil starts washing out the grease from the birf and inner knuckle area, the grease you add is not going to move up stream, and eventually only birf soup will remain in the inner area no matter how much you add,

If the inner seal is holding and the birf is properly serviced then you may get some of the grease to move back and forth between the inner and outer parts over time




P.S. Just a side thought would have been nice for Toyota to make the stub shaft a bit larger in Diameter with a narrow tube in the middle with a zerk fitting at the drive plate end, you could pop the dust cap and inject grease directly into the bell of the birf purging out old grease and wear metals, oil etc in the cv joint

A machine shop could bore a small hole the stub shaft but it would weaken it, not sure if the CV would still be the weak spot afterward

 

[Scamper]

Think it would be possible to drill and tap a hole for a zerk right behind the upper trunion bearing on the knuckle? That way you could pump grease right into the knuckle cavity behind the birf. Of course, you'd have to do this when the knuckle was apart for a repack.


BTW Raven: nice diagram!

 

[Arya Ebrahimi]

Hmmm, Raven, you might be onto something for Bobby Long to incorporate into his longfields. The inner most part of any axle shaft adds very little strength. That's how the comp guys get away with gun-drilling 35-spline D60 shafts and still not breaking too often. Granted a 35 spline D60 shaft is 1.5" across, but they're drilling 1/2" diameter all the way down. I think you could get away with a 3/16" hole and still maintain strength. If you guys think my thinking is correct, I'll contact Bobby and see what he says.

 

[cruisermaine]

where would the old material purge from? You wouldn't want to blow one of the seals. Are you thinking the existing grease port? Sorry if this is a dumb question but I haven't yet done a front axle tear down so I'm not up to speed on this yet.

 

[erics_bruisers]

nice pic, raven -- i might make a t-shirt out of it --



e

 

[Curran]

where would the old material purge from? You wouldn't want to blow one of the seals. Are you thinking the existing grease port? Sorry if this is a dumb question but I haven't yet done a front axle tear down so I'm not up to speed on this yet.

The old grease could purge from the existing plug hole.
I think the hole through the stub axle sounds like flippin' great idea. IIRC back to the old college days, sometimes the a hole in the middle of an axle can reduce the axial strain on a component and result in a more durable axle. But that class was several years and many manny beers ago. A grease supply channel doesn't need to be verry big. 1/8" inch?

 

[Tools R Us]

Looking into it, the problem is drilling a 1/8" hole centered through 8" of hardened steel. Not something your going to do with a Makita battery drill.

http://www.gearingdynamics.com/greasecv.htm

 

[ryanjl]

Great diagram Raven! Hope you don't mind, I added some descriptions to it for those who are not familiar with the area.

The only way you could possible get grease into the inner birfield cavity, where it needs to be, is by drilling a hole through the stub shaft. Niether the abs hole nor the upper or lower trunion holes will get the grease inside the birfield.

 

[RavenTai]

Looking into it, the problem is drilling a 1/8" hole centered through 8" of hardened steel. Not something your going to do with a Makita battery drill.

http://www.gearingdynamics.com/greasecv.htm

LOL, not only has somebody already thought of it they already are already making them for the smaller birfs, yes defiantly a machine shop operation, hopefully someone with the skill and tools could bore a 1/8" or better yet 1/16" hole centered down the birf

Seams to me that a hole would make it weaker even if only by creating a stress riser, mass for mass a hollow tube is stronger but that implies a larger diameter for the hollow one, here we are making it hollow without making it larger, but I don’t think stub shafts are prone to breakage so there may be some extra strength there to take away without any problem. The hole should be as small as possible and the bore as smooth as possible

Yes somebody contact bobby long and see if he thinks this could be added or possibly an option

I am thinking if you only add a little grease at a time the old stuff will make its way to the wiper seals and out, if you added to much it would probably push its way past the inner axle seal and mingle with the gear lube

Shocker, nice labeling, I got that from the new car features manual, all I did was blacken the background

 

[Arya Ebrahimi]

I sent Bobby Long a PM on PBB, I'll report back with his reply.

Ary

 

[semlin]

Awesome diagram and interesting idea on the hollow birf stub axle shaft. The only trouble is the only way to implement the mod is to pull the birf at which time you probably don't need to go back and use you new mod for another 60,000 miles!

On the other hand it seems to me this is a doable mod to an oem birf. There is already a centred threaded hole at the outer end of a stock oem birf to put in a temporary positioning screw. This gives you an accurate starting point from which to drill and also a threaded spot to install a cap to prevent grease migration out of the birf into the hub and to install a temporary zirc when servicing. I am betting a machine shop could drill it fairly cheaply since all they have to do is clamp onto the birf shaft amd make sure it's vertical and then tap down through the existing hole without touching the threads. Give me a good enough drill bit and I could do it on my drill press.

I am still not so sure I agree with the universal pessimistic response to the abs sensor idea. Unlike the grease plug hole, the abs sensor hole allows very good access to the inner knuckle housing. If you tucked a curved grease hose into the sensor hole and snaked it into the inner knuckle housing to the top of the birfield bell housing and then pumped, I think a lot of grease would get into the inner housing area beyond the birf bell housing. Once you get it in there dripping down the open face of the birf bell and on the axle shaft some of it will find its way into the inner birf housing the same way that diff oil leaking through the axle seal manages that feat. I am assuming that this happens either by centrifugal force coming off the axle shaft or because the bell housing is partially immersed in grease at the bottom and is constantly dipping into this reservoir.

It would be good if someone tested the viability of this theory with an actual exposed birf housing. If it worked then so long as your axle seal had not failed you could do this instead of a birf job.

 

[nakman]

This is a cool thread, those diagrams are sweet Raven. I kind of side with the pessimistic though, and agree that the only real way to get grease where it needs to go is to yank the birfield and repack it. Removing the ABS sensor is a little risky, like R2 said above.. plus it opens the door for allowing dirt & other crap to now fall into that nice big hole, much worse IMO than running a little low on grease, I'd rather have less clean grease than more contaminated grease.

Personally, I never add grease to mine, would prefer to just tear into it every few years and see what's really going on, it's a Saturday well spent.

 

[e9999]

Awesome diagram and interesting idea on the hollow birf stub axle shaft. The only trouble is the only way to implement the mod is to pull the birf at which time you probably don't need to go back and use you new mod for another 60,000 miles!

On the other hand it seems to me this is a doable mod to an oem birf. There is already a centred threaded hole at the outer end of a stock oem birf to put in a temporary positioning screw. This gives you an accurate starting point from which to drill and also a threaded spot to install a cap to prevent grease migration out of the birf into the hub and to install a temporary zirc when servicing. I am betting a machine shop could drill it fairly cheaply since all they have to do is clamp onto the birf shaft amd make sure it's vertical and then tap down through the existing hole without touching the threads. Give me a good enough drill bit and I could do it on my drill press.

I am still not so sure I agree with the universal pessimistic response to the abs sensor idea. Unlike the grease plug hole, the abs sensor hole allows very good access to the inner knuckle housing. If you tucked a curved grease hose into the sensor hole and snaked it into the inner knuckle housing to the top of the birfield bell housing and then pumped, I think a lot of grease would get into the inner housing area beyond the birf bell housing. Once you get it in there dripping down the open face of the birf bell and on the axle shaft some of it will find its way into the inner birf housing the same way that diff oil leaking through the axle seal manages that feat. I am assuming that this happens either by centrifugal force coming off the axle shaft or because the bell housing is partially immersed in grease at the bottom and is constantly dipping into this reservoir.

It would be good if someone tested the viability of this theory with an actual exposed birf housing. If it worked then so long as your axle seal had not failed you could do this instead of a birf job.

I don't get this, from the diagram above and going by (shot) memory, it doesn't look like the ABS sensor is much -if any- closer to the open end of the bell then the existing access hole. Seems like the way to go would be to snake a flex or insert a piece of bent tube in the latter to get it close to the bell opening. Still, the grease won't go in much probably.

As far as drilling the hole in the stub axle, doing the hole straight is no problem, they do that all the time with self-centering bits for drilling gun barrels. Trivial. But here the metal may be harder, don't know about that...

E

 

[e9999]

why not drill and tap the main axle housing just above the bell opening so you can squirt it in? isn't there a spot that is not swept by the moving felt seal etc?
E

 

[reffug]

Great diagrams guys, sometimes I just wonder where do you come up with the time?