Greasable birfield CV joints done

[Beowulf]

And you don't need to be injecting a ton of new grease all the time. Just a pump or two at each oil change should do wonders. And with this approach the new grease is getting added right where it's needed too!

I am with Tom on this one. I cannot see why you would fill the knuckle cavity with grease if you have this setup. The only thing that needs grease is the inside of the birfield joint and we pack the knuckle because there is no way to get to the inside of the joint so we have to rely on the huge quantity of grease to do the job.

Thoughts?

-B-

 

[spdwaver]

This really needs to be in the FAQ.

 

[e9999]

Not sure you will need a safety valve.
What if you just open the square plug before pumping grease, and just stop when grease comes out the top?

well, if you have to go to the trouble of opening up the plug, you're halfway done pumping grease in there through the plug. (Most of the time I spend filling the knuckles through the plug is cleaning the dirt from the area first.)
Much less compelling to install the zirks in that case.

 

[Shipwreck]

I am with Tom on this one. I cannot see why you would fill the knuckle cavity with grease if you have this setup. The only thing that needs grease is the inside of the birfield joint and we pack the knuckle because there is no way to get to the inside of the joint so we have to rely on the huge quantity of grease to do the job.

Thoughts?

-B-

I would still be inclined to fill the cavity 3/4 full with grease . In addition to lubricating the inner ball and cage I think the grease also aids in dissipating heat. More grease = less thermal breakdown.

Thoughts?

 

[FirstToy]

I am with Tom on this one. I cannot see why you would fill the knuckle cavity with grease if you have this setup. The only thing that needs grease is the inside of the birfield joint and we pack the knuckle because there is no way to get to the inside of the joint so we have to rely on the huge quantity of grease to do the job.

Thoughts?

-B-

Well you need grease to keep water out. Also, it doesn't make sense to use as little grease as possible. Considering grease is a few bucks and everything else in there is a lot more $$, I think just following the FSM is best.

This is a great way to make sure the birf is lubed though, I really like it.

 

[Pin_Head]

This is a fix for what problem? Birfields routinely go for 150 - 200 K and I have never seen one fail from lack of lubrication.

 

['74 UA FJ]

well, if you have to go to the trouble of opening up the plug, you're halfway done pumping grease in there through the plug. (Most of the time I spend filling the knuckles through the plug is cleaning the dirt from the area first.)
Much less compelling to install the zirks in that case.

Is it really that much trouble? I grab a crescent wrench and open it up in approximately 2 minutes...

 

[Wrench]

Ya why not just use the square knuckle plug? That's why Toyota put it there. This is just way to obsessive and over thinking things. People are so paranoid.

 

[Kernal]

It's all good (the discussion), that's why we're here. For sure I don't have the right answer as to how much to grease or even if it needs extra grease in-between service intervals; probably just a few pumps during oil changes at the same time I'm greasing the U-joints and yolks, and probably open the plug to see if I can see anything. If grease oozes out of the knuckle port I'll know I've added too much; IIRC the FSM says 3/4 full so don't want to overpack it.

 

[NLXTACY]

I finally have my replacement birfs sitting on my work bench. This is SOOO getting done

 

[Ebag333]

IIRC the FSM says 3/4 full so don't want to overpack it.

That's because OEM there is no way to relieve the pressure if it builds up in there, which results in a blown seal.

The mining trucks are all setup with greasable birfs (same basic idea) and a relief valve. They get something like 5-6 pumps of grease a day, and go 150k-200k on the same set of birfs.

They're also heavily used, driving uphill or downhill and turning side to side pretty much all day. Little straight level driving.

If it works for them, it should work for us. I plan on either getting a set of the greasable birfs shipped across the pond or a new set of OEM birfs and having this mod. Then drill and tap the fill plug for a relief valve.

 

[Beowulf]

This is a fix for what problem? Birfields routinely go for 150 - 200 K and I have never seen one fail from lack of lubrication.

We've seen pictures of several that have failed due to lack of lubrication. I think the main advantage of this mod is to forego the 60k birfield repack interval. With this setup you just squirt a few pumps at each oil change and drive the truck until the front seals are worn out. You'll only need to do the wheel bearing repacks at 30k intervals.

Like James said, keeping water out would be a good reason to fill the knuckle cavity he is right that grease is cheap.

-B-

 

[Kernal]

Finally got around to installing the greasable birfields, thought mudders would like to see some greasable birf porn. I counted the pumps as I greased them using a standard size manual grease gun loaded with Valvoline Palladium grease. After priming the grease gun with about 10 pumps I then attached it to the first birfield which took 40 pumps before the grease just started to show on the balls after moving the cage/star/balls around with the axle shaft (middle photo). I was a bit surprised that it took so many pumps just to barely fill the bottom of the bell. It took 50 pumps for the grease to just start to oozing out through the cage while the axle shaft/birf was off center, the last photo shows about 60-70 pumps. By experimenting how to best pack the birfield using this method I learned that by rotating the birfield and axle in small increments while at the same time keeping the birfield at an angle to the axle shaft it allowed the grease to push out past each ball/cage/star opening. If I kept the axle shaft and birfield in line with each other you could feel the hydraulic pressure try to push everything forward although grease would still ooze out from wherever it could. For the birfield attached to the short shaft I pumped 85 times until I called it good, for the long shaft birfield I continued to pump until 100 which was too much, I just wanted to see if any air would come out and none did. The birfields were completely and easily packed using this method.

 

[Kernal]

Here are some more photos, first is about 55 pumps, middle is 100 untouched, and last is 85 after I smoothed out the grease that had been packed by the grease gun. It took one tube of the Valvoline Palladium grease for both birfields. From what I've seen here about 85 pumps would completely pack a dry birfield and about 60 pumps should be enough to replace most of the old grease in an already packed birfield.

 

[Ebag333]

Great info, thanks for sharing.

 

[Dutchie]

Great Mod !

 

[Dave 2000]

I would like to add to this if I may? My now sold heavily modified Discovery used hardened CV's (Birfs) and shafts/flanges ect and they could wear if used every day similar to the Longfields ect. I did not want to drill as per the OP (hats off to OP BTW) so to enable me to use them as a daily driver I elected to grease on a super regular basis i.e. once a month! I also decided to try an experiment, I packed with molybdenum disulphide grease (grey) and then one month later packed with the same type of grease but red! The following month I took apart the CV for an inspection and found to my disatisfaction that the CV still contained quite a bit of the grey grease and much of the red still outside the CV cage! It could be argued that the presence of the new red grease prevented the grey being expelled and it was in fact still doing it's job but it's worth noting the 'new' grease did not get fully into the joint. So I stripped and cleaned anyway and of course there were no issues to be found but all the same AFAICT unless you have a small oil seal leak that will lead to some 'soup' in the bif housing then the new grease will NOT be reaching the inside of the birf so may not do much to reduce wear.

So a greasable CV/Birf is IMHO the way to go and may indeed be the way forward to being able to use the Longs on a daily driver.

Just my 2 cents

regards

Dave

 

[ShawnTRD]

I know what I'm doing when mine are out...

 

[Kernal]

When I took my birfields apart I found that in my PS birf (less worn and tighter) there still was some relatively normal looking grease inside the bell or cup of the birfield even though I had gear oil and birf soup leaking out of my knuckles for many months. This even after I had sprayed about half a can of brake cleaner and half a can of carb cleaner into the star/cage/balls while the birf was still attached to the axle shaft. Previously I would have thought that the birf soup would have washed all the solid grease out of the birfield but it apparently didn't. It seems like the old grease already in the birfield does not mix completely with any new grease (or soup) we add to the knuckle?? I guess one advantage of being able to grease or pack your birfs via the zerk to the bottom of the birf cup/bell is that you are forcing out the old grease which otherwise is stuck there unless you disassemble it. From the photos you can see that it works like a bearing packer, out with the old in with the new.

About prolonging the life of Longfields; I'm not the expert (on anything) but IMHO I can't see this mod helping that much (don't even know if it would help prolong the life of OEM style birfs). The Longs apparently wear out very quickly due to the lower Rockwell Hardness and before the grease inside the bell would be used up or degraded IMHO. I think the main advantage of this mod would be what it was originally developed for, forcing out any water or grit that has gotten into the knuckle before it gets into the birfield (I'm guessing), and replacing old grease with fresh grease inside the birfield bell/cup. It could decrease the frequency of having to pull the birfields out for service particularly if the Marlin HD axle seals are used, at least that's what I'm hoping for.

Edit: Trivia point: one thing about the number of pumps it took to completely pack the birfield; seems like last time I added grease to my knuckles using the inspection/fill port I didn't get near as many total pumps (over 200) out of one tube of grease using this same gun and grease, think I got a little over 100 when just pumping into the knuckle. So I'm thinking maybe when you pump through a zerk each pump delivers less volume than if the hose is not connected to a (restrictive) fitting. Either way, one 14 ounce tube filled both birfields packed this way and then some.

 

[cme4lyt]

Great write up....

Thank You for taking the time to detail this mod. This is why this forum works so damn well !!

I'll be contacting you in a couple of weeks for more details about the guy who did your mod. I'll be pulling my birfs soon and I am sooooooo doing this.

Rgds....