Birfield joints are normally fastened to
the inner axle with a small circlip. This clip is a devil to install, and even
harder to remove. Installation requires ten or twenty spare
fingers, and a sailor's vocabulary. Basically, you put the clip onto the inner
axle, then slide the inner axle into a greasy Birfield while trying to keep the
slippery little clip compressed enough to stay in the groove -- all so that you
can slide the axle and clip into the Birfield. When the clip slides in past
inner bearing race, the clip expands and retains the axle in the Birfield. Removal, once you get the inner axle and
Birfield out of the axle, is even more entertaining. You can use a CV-joint
splitting tool, or beat the hell out of the joint... I 've had some success
repeatedly dropping the axle and Birfield assembly into a pipe that would fit
the axle but not the Birfield. All of these techniques basically do the same
thing, force the Birfield to cut through that circlip. Tired of fussing with those clips, Marlin
Czajkowski, of Marlin Crawler fame, started thinking. The clip isn't intended to
keep the Birfield from pulling off the axle and heading outboard from the
centerline, because the Birfield's stub is stablized and constrained by the hub
and spindle. The only real purpose for this clip is to prevent the axle from
sliding out of the Birfield, toward the center, and into the differential.
Normally, the axle floats inboard and outboard a small amount, constrained by
the clip at one end, and a bigger c-clip on the axle.
 | The tack weld should be placed in the location shown in the picture,
on the splines that go into the 3rd member. The last 1 3/8 - 1 1/2"
of the splines should be left clear. The weld needs to ground down so
that it is the same height as the splines. |
A few more moments thinking, and Marlin
had his solution - a couple of tack welds at the differential end of the
inner axle shaft. These tack welds prevent the inner axle shaft from jumping out
of the Birfield and into the differential, and you'll never have to fight with
those little circlips again. Trail repairs just got much easier... and if you
want never to worry about breaking a Birfield again, you can install Marlin's
new Marfield joints. Marlin tacks two places on the axle,
just over one and a half inches outboard of the inner end of each axle where it
slips into the differential (red dots in the diagram). Any old welder will work:
arc, MIG, or TIG. Just tack it lightly, you want to deposit a small amount of
rod but minimize heat transfer. When you reassemble, you can leave out the end
circlip (blue arrow in the diagram), but be sure to include the
square-shouldered clip (green arrows in the diagram). 
Total cost is a few inches of welding
rod. The big cost on this one is time --- undressing a Toyota front axle far
enough to get to the Birfields and inner axles takes a while. Next time you have
the axles apart, though, you should give this serious consideration. If you would like to have Marlin place
the welds on your axles just send the axles in and he will add the tack weld for
free!
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