Separating and reassembling the birfield and inner axle assemblies (1 Viewer)

[96r50]

This thread is a result of Driley's front axle rebuild thread, and will hopefully clear up some of the questions associated with separating the birfields from the inner axle shafts, reassembling the birfields, and reinstalling the axle shafts. Some people may do this simply to clean out all the old grease during a rebuild, others may swap the birfields to the opposite side to coax some more life out of them, and some unlucky folks may do this after their tire passes them on the shoulder of the road

Part A: Separating the birfield and inner axle.

1. Buy a 4' piece of 1.5" inner diameter ABS pipe (the black plastic stuff). Cut it so it is 4"-6" longer than the long side inner axle shaft
2. Place the inner axle shaft into the pipe so the birfield sits on the top end of the pipe.
3. Place a heavy folded up shop blanket on the floor (or stuff the bottom end of the pipe with a couple of shop rags). This will prevent damage to the splines on the differential end of the inner axle when you slam the end of the pipe against the floor/blanket.
4. Hold the pipe in one hand and the stub shaft of the birfield in the other and slam the end of the pipe against the floor/blanket.
5. Repeat until the inner axle separates from the birfield and drops to the bottom of the pipe. Presto!
6. Congratulate yourself for not putting too many dents in the floor
7. Remove the old snap ring from the axle shaft, disassemble the birfield, and clean all the old grease off. Keep all the parts together and label what side they came from.
8. Repeat steps 2 through 7 with the short side assembly.


Part B: Rebuilding the birfield.
These photos courtesy of Driley (it's still too cold to wear shorts in my neck of the woods!)

1. Clamp the empty birfield (tulip) open-end-up in a soft jawed vise.

2. Take a look at the cage and notice that it has a flat edge and a tapered edge. The flat edge goes to the outside of the truck (facing down into the birfield in the vise).
3. Next look at the star piece. One edge of the splined hole (where the axle engages) has a groove where the C-clip will sit when the inner axle shaft is installed. This faces the outside of the truck (down into the birfield in the vise). The edge on the other side of the star has splines that taper down slightly as they near the edge. This is to help guide the axle splines during reassembly.

4. Assemble the cage and star, keeping a close eye on the orientation of both parts, and install into them into the birfield.

Tapered edge (cage) and guide splines (star). This side faces towards the differential (up in the birfield in the vise).

Flat edge (cage) and C-clip groove (star). This side faces the outside of the truck (down into the birfield in the vise).

Installing the cage and star into the birfield.

5. The 6 balls can be installed one at a time by aligning the grooves in the star with the slots in the cage and the grooves in the birfield, and then tipping the star and cage assembly up. The ball should drop in to the exposed space with little to no force (depending on the mileage on the birfs). If you have to push it in with more than one finger, something might be amiss. Check everything again. Drop the remaining 5 balls in, and presto, you have one assembled birf!

6. Drink up!
7. Now, take it all apart, coat everything with moly grease (leave a bunch of grease inside the birfield) and put it all back together again. Practice makes perfect, right?


Part C: Installing the axle shaft.
These photos courtesy of woody (was it that tire? )

1. Decide which axle shaft is going in which birfield. If the birfields are clicking during turns, swapping them to to opposite side can extend their useable life somewhat.
2. Install the C-clip in the groove in the axle shaft. It will be loose.

3. Use a ziptie or hose clamp on top of the C-clip to compress the clip around the axle shaft.

4. Align the greased axle splines with the greased splines in the star and press the axle into the star. As the ziptie/hose clamp reaches the star, it will keep the C-clip compressed until it slides into the star.

5. Push the axle in the rest of the way, remove the ziptie/hose clamp and check that the axle will not come out of the birf.
6. Congratulations, you now have one assembled inner axle assembly!
7. Repeat steps 2-6 for the other birfield and inner axle shaft.

 

[bbb18c1]

Thanks for putting this together!
I am planning to do my axle rebuild on the next few weeks and I was unsure if I wanted to do the birf swap or not. Now that I can see it isn't too hard of a job, I may as well do it since everything is apart!

and btw that brif isn't in a soft jawed vise. It appears to be in between a mans crotch

1. Clamp the empty birfield (tulip) open-end-up in a soft jawed vise.

 

[Tenzig Norgay]

I personaly am happy you managed to fit step 6 in so perfectly in each catagory. A++ It makes the job look downright enjoyable

 

[Driley]

Adam, it snowed here on Tuesday and is supposed to be in the 80s by Sunday! Living at the base of a mountain range breeds some weird weather!

As far as a soft vise, I have been using the Susan Summers Thigh Master so I think I can get at least a couple hundred pounds of force!

Nice job Adam! Thanks for putting that together!

Riley

 

[bbb18c1]

A serious question now:

Would it be better to pack the birf after installing the c clip? It seems like it will be hard to line up the splines if there is grease in the Birf.

 

[Driley]

I was thinking the exact same thing. I seriously think that it would be better to get the axle and birfield connected prior to filling with grease. When I break everything apart, if I do not do the martack method, I will put a light coat of moly grease in the birfield then install the cage/star/balls then get the axle shaft engaged with the circlip prior to loading the birfield with grease. That way I will know that the clip is where it is supposed to be. I really, really do not want to open this thing up again for at least 60,000 miles! The reason I did not see the broken clip was because of the grease. I know now what to look for, but at the time, I just thought I was OK. You live, you learn...

Thank you for the observation.

I am not happy that I have to go back in so soon, but I am still learning.

Riley

 

[Beowulf]

Would it be better to pack the birf after installing the c clip?

I would not recommend this. Once the axle shaft is in the hole you loose access to the inside of the joint. There is a great picture that someone took while using a grommet to fill the birf with a grease gun. I'll see if I can find that picture.

-B-

 

[psfpilot]

A serious question now:

Would it be better to pack the birf after installing the c clip? It seems like it will be hard to line up the splines if there is grease in the Birf.

I would not recommend this. Once the axle shaft is in the hole you loose access to the inside of the joint. There is a great picture that someone took while using a grommet to fill the birf with a grease gun. I'll see if I can find that picture.

-B-

I gave it a light coating of grease to ease assembly and then used a grease injector attachment on the grease gun to backfill grease behind the cage/balls/star assembly after it was fully reassembled with inner axle shaft c-clipped in place.

 

[turbocruiser]

I would not recommend this. Once the axle shaft is in the hole you loose access to the inside of the joint. There is a great picture that someone took while using a grommet to fill the birf with a grease gun. I'll see if I can find that picture.

-B-

Agreed, I fully fill the birf as its assembled then take a convex rubber cone washer which fits over my pneumatic grease gun and is a little larger than the opening to the cage to really get the grease in there. When I get to the point of putting the shaft through grease gushes out everywhere, now that's the proper packing; anything extra can simply be smeared on the shaft all over and on the seal all over to avoid any damage done to the seal while installing the assembly into axle housing. HTH.

 

[bbb18c1]

Agreed, I fully fill the birf as its assembled then take a convex rubber cone washer which fits over my pneumatic grease gun and is a little larger than the opening to the cage to really get the grease in there. When I get to the point of putting the shaft through grease gushes out everywhere, now that's the proper packing; anything extra can simply be smeared on the shaft all over and on the seal all over to avoid any damage done to the seal while installing the assembly into axle housing. HTH.

How do you line up the splines with that much grease in there?
Do you just go by "feel"?

I was watching the axle rebuild DVD and in it, they repacked the Birf without disassembling it.

Any tips on lining up the spines after filling it up with g rease?

 

[turbocruiser]

How do you line up the splines with that much grease in there?
Do you just go by "feel"?

I was watching the axle rebuild DVD and in it, they repacked the Birf without disassembling it.

Any tips on lining up the spines after filling it up with g rease?

It is basically by feel although I always take my finger and flush a fingertip's worth out of way to see the splines too. But, it is basically by feel and it is really extremely easy to feel it when its right.

No insult intended to Mariachi but I basically strongly disagree that the birf is properly packed while assembled and because its basically so easy to disassemble the birf, inspect everything inside and reassemble the birf I just don't see the sense in "saving" the time there. Again no insult intended to Mariachi. I do my birfs every 50K and my bearings every 25K and even with extra intervals like that I simply won't save the thirty minutes to try without disassembly and reassembly. One thing is that you cannot properly clean the birf without disassembly ... many moons ago I soaked my birfs for some time in my motorized parts washer while I was working on some #6's ... I was amazed that at time of disassembly there was a wad of dried up dirty grease at the bottom concave bit of the birf. The other thing is that you cannot completely inspect the birf, the balls, the cage etc without disassembly. And, the last thing is that if there is an air pocket at the bottom of the birf, it will take some time to totally migrate out of there and get gooped back up by good grease ... during that time you are actually "running dry" and it isn't worth the worry to me. Keep in mind I'm really OCD about all these things so several grains of salt are always warranted with anything I advise! JMHO but I hope it helps.

 

[ndega01]

Does anyone know if swapping the birfields would cause ABS problems. After swapping my birfields I took my rig out for a test drive and found that my ABS was activating when the truck was coming to a stop. The truck pulls to the left and the break pedal vibrates. The brakes worked fine before doing the complete knuckle replacement and swapping the birfields from one side to the next. Any ideas as to what my ABS problems could be?

 

[wxm]

Does anyone know if swapping the birfields would cause ABS problems. After swapping my birfields I took my rig out for a test drive and found that my ABS was activating when the truck was coming to a stop. The truck pulls to the left and the break pedal vibrates. The brakes worked fine before doing the complete knuckle replacement and swapping the birfields from one side to the next. Any ideas as to what my ABS problems could be?

Don't think that has anything to do with swapping birfields. Are you sure that you put those shims back properly for the upper and lower bearing housing? If so, I'd double check the housing are seated properly and torqued to the right number, especially the lower one. The FAQ covers that in great details.

 

[ndega01]

WXM are you talking about the trunions? I'll check them out and see. But I'm pretty sure they were done just like the forum on rebuilding the front axle said to do.

 

[wxm]

WXM are you talking about the trunions? I'll check them out and see. But I'm pretty sure they were done just like the forum on rebuilding the front axle said to do.

Yes, the trunion bearing housings. Top has two nuts and bottom has four. They should be torqued down to 71 ft-lb. The top may also have shims under. They are for preload adjustment and should be put back the same as they were taken off. The bottom takes some effort to be seated properly especially the driver side. Here is quoted from the FAQ by IdahoDoug

[FONT=&quot]I took some extra time on this repack to consider common failures people have experienced after repacking their birfields:
- loosening of the 4 nuts/studs on the bottom of the knuckle
First, the 4 knuckle bolts. I have done this 3 times and have always had to fiddle with reinstalling the steering arm on the knuckle - which is attached by the 4 nuts. The fit of the arm is extremely precise and will often bind while you are tightening the bolts before it is all the way on. This will leave a gap of only a few thousands of an inch, but the arm is definitely NOT on. I verified this today by playing with it a few times and it sis easy to do. So I used a hammer to tap the arm upward every few turns of the nuts, preventing it from binding. It worked perfectly. Considering the fastening system is quite bombproof, I think these failures are simply due to the steering arm binding up just before seating all the way. Many have bought the newer torx head bolts (including me!) in fear of this loosening phenomenon, but I think tapping it with a hammer continuously until it is all the way home solves the problem. I did not use the new bolts, and am not sure what I'll do with them.

So, I'm suggesting that the FAQ birfield repack instructions should be amended to add light tapping with a hammer as the nuts are tightened on to prevent this bind.

DougM[/FONT][FONT=&quot]

[/FONT]

 

[Kernal]

Anyone have a photo of where we should be tapping so front axle virgins (like me) don't bend something? How hard, like tap tap with a 2 lb deadblow, or bang bang with a 5 lb sledge? Is this required because we aren't disconnecting the tie rods??

 

[turbocruiser]

Anyone have a photo of where we should be tapping so front axle virgins (like me) don't bend something? How hard, like tap tap with a 2 lb deadblow, or bang bang with a 5 lb sledge? Is this required because we aren't disconnecting the tie rods??

Kernal, I wouldn't recommend the hammer technique; it is a pretty brutal process. Instead, use the PVC tube technique where you take a 2.5 to 3.0 inch diameter PVC tube about 4 foot long, stuff several heavy rags in one end, hold the PVC tube vertically with the rag end down, put the assembled birf in the other end with the shaft end down, hold the birf and tube together tightly with two hands, pick the whole thing up a few feet and slam the rag end of the PVC tube down towards something super firm like concrete. Within a few slams down the shaft will spit out safely and get caught and cushioned by the rag end, and you then can completely clean and properly pack the birf. Always use new c-clips when you reassemble. HTH.

 

[96r50]

Anyone have a photo of where we should be tapping so front axle virgins (like me) don't bend something? How hard, like tap tap with a 2 lb deadblow, or bang bang with a 5 lb sledge? Is this required because we aren't disconnecting the tie rods??

I tapped between the four knuckle studs as well as on the front and rear edges of the steering arm. I used solid taps with a 16oz ball peen hammer, but I wasn't wailing on it. The point of the tapping is to ensure that the steering arm seats properly in the knuckle housing, and I would do it regardless of whether or not I disconnected the TREs.

 

[turbocruiser]

I tapped between the four knuckle studs as well as on the front and rear edges of the steering arm. I used solid taps with a 16oz ball peen hammer, but I wasn't wailing on it. The point of the tapping is to ensure that the steering arm seats properly in the knuckle housing, and I would do it regardless of whether or not I disconnected the TREs.

Hmmm, maybe I misunderstood the question then ... are we talking about disassembling the birf or seating the trunions?

 

[96r50]

My understanding was that Kernal was asking for clarification of IdahoDoug's quote in wxm's post (#15).