Ever wonder what your front axle would look like *without* all that
grease an oil caked on it? Well, I did, but didn't want to find out
*that* bad. However, after getting my Birfield joints replaced with
Marfields, I started experiencing an oil leak on the passenger side of
the axle. Attributing it to a worn felt and rubber seal on the steering
knuckle, I picked up a new seal kit and replaced the outer seals on
both sides. It seemed to work for a few months then all of a sudden my
little leak was a BIG leak, I had oil all over the rim, tire and
underneath the truck.
Here's how I did this project:
Start by getting a container to hold the nuts/bolts in.
Next, cone washer encounters of the
I tried the above technique on my cone washers and found it worked on a
few, but not all of them. After some experimenting, I found that a
narrow bladed screwdriver and small hammer worked 100% of the time.
Just line the screwdriver blade up with the cone washer slot and give
the screwdriver handle a few raps with the hammer. Anyway, the idea is
that you push something into the slot in the washer, expanding it a
bit, causing the cone washer to push against the tapered hole and it'll
just climb right up the stud. Works like a charm and is much more
elegant that beating on the hub with a big club! See below for an
animation of the process by Joshua Carlson:
Then again, on my spare axle, which appeared to be totally stock and
had never been taken apart, the screwdriver technique didn't work but a
quick tap with a hammer on the hub popped off one after another cone
washer with ease (several of which flew off with such force, that if I
didn't have the nut loosely on the end, I would have lost them as they
flew off into the grass).
A third technique is to use a small chisel to turn the washers and
break them loose. Fit the end of the chisel into the slot of the washer
and angle it to one side. Tap with a hammer to loosen the washer.
A forth technique for removal, submitted Peter Bonefant of Ontatio
Canada, is to simply remove the stud and the cone washers as a unit, by
double-nutting the threaded end of the stud, then back out the stud
from the hub body. I imagine this would work well for cone washers that
are slightly more deformed. Sounds like a good last resort, a bit more
time consuming, but should work in most every case.
The important point is that there are many techniques to try, if one
doesn't work, try another...
Now that you've the hub completely disassembled. It's time to get the
races out of the hub body for the bearings you want to replace. I use a
brass bar. It's sort of tricky getting those races out since there
isn't a very large surface of the race to hit on. Just hit a little on
this side, a little on that, side, going back and forth and it'll come
out, but definitely use a brass *something*, not steel!
Cone washer encounters of the second kind:
So, what do you do with that big, greasy Birfield/axle assembly. You
really need to clean it well and the best way to do that is to separate
the axle and Birfield. A large metal tube, long enough for the inner
axle to slide into and small enough to contact the Birfield housing
works great. Put a rag at the bottom of the tube (to prevent damaging
the splines when it pops loose), drop the inner axle into the tube and
slam the whole Birfield assembly onto the tube until the inner wire
clip breaks and lets the inner axle drop out.
Then, clean that sucker out really well. I used a parts washer and left
the solvent pump circulate solvent inside the housing for an hour of
so, to dissolve every trace of crud in there. Then dry it off and use a
blast of brake cleaner to get the solvent residue off. Refill the joint
with CV Joint grease, its specially formulated for CV joints, of which
the Birfield is a variety. Some folks use a moly fortified wheel
A couple of tips for handling the bearings and races.
That is the question.
I say tack, but you need to do it in the right place. I had my inner
when the Marfield joints were installed and guess what, the MarTack
led to the oil leak that led to me rebuilding my axle. On the left,
you can see the "official" MarTack, place 1-3/8"
from the end of the splines. On the right, you'll see my TrueTack
spaced only 1-1/8" from the end of the splines. My front TrueTrac
differential carrier is apparently a bit narrower than the stock unit,
upon which the crucial MarTack
distance was determined.
I recently swapped my 4-cyl. 3rd member w/ TrueTrac for a high-pinion
FJ-80 diff with an ARB RD23 air locker. I found that once again, the
"right" location for the tack welds was between 1-1/8 and
1-1/4". This time I also made sure and placed all three welds, I
had trouble with a single weld wearing through.
Anyway, what the MarTack does, is to prevent the inner axle from
slipping too far into the axle housing. This serves two purposes, one
is to keep the spline engagement about equal between the differential
carrier splines and Birfield, second is to keep the raised, machined
oil seal surface under the inner oil seal. In the picture on the left,
you can see the inner axle pulled out to reveal the shiny raised
surface. The picture on the right shows how far the axle should push
into the housing. You'll notice the flat surface has just disappeared
into the seal, but no more. Before moving the tack weld, it went a full
1/4" farther in, causing the oil seal to leak around the smaller
axle shaft itself.
The c-clip on the axle prevents it from moving too far into the
Birfield, so between the tack and clip, the inner axle can move about a
little but not too much. You can feel when the inner axle seal drops
off the sealing surface the axle can move around a bit more. If this
can happen by hand, it WILL happen when you put the axle back together
and it WILL leak gear oil and you WILL get to rebuild the axle again! I
used a depth gauge on a cheap caliper to measure how far the axle moved
in after the axle dropped off the seal and used this to place the final
tack weld. Once I got it set right, I added two more tack welds around
the same depth, 120° apart, ground them flush and that was it.
Some differentials don't seem to require any tack welds or clips inside
the Birfield as the "guts" of the diff prevent the axle
moving in too far. Conversely, other types need something to prevent
this from happening. On the other hand, you don't want to put the tack
welds any closer to the end as you need. The axle should have room to
float around a little, otherwise it will put pressure on the inner race
of the Birfield, probably not a wise thing to do, either.
Anyway, you have three options for installing inner axles:
Which option you use depends on your axle and your differential
carrier. Use whatever works for your situation.
Here is another writeup
showing a very similar technique for determining the proper MarTack
Of course the above implies that you have separated the Birfield joint
from the inner axles. I find a length of metal pipe just large enough
to slip the inner axle into and long enough to enclose the inner axle
works well. Stand the pipe up on end on a rigid surface, concrete or
rock works best; dirt, wood, and asphalt can be too "bouncy".
Put a rag down the tube to protect the end of the inner axle and drop
the whole assembly down onto the end of the tube. The impact and
inertia of the inner axle will pop it loose from the birfield, usually
leaving the inner clip intact. If a low drop won't work, gradually
raise the birfield up higher and drop it. On the short side axle, you
may need to "throw" the axle into the tube to get it loose.
An alternate method, and a good trail fix, is to ram the inner axle and
birfield into the round tube crossmember that runs across the top of
the frame in the rear wheel wells. Its the right size to fit the inner
axle in. Do the long side first and then you can use the long inner
axle to push the short side axle out if it stops in the middle.
Then you may feel inclined to clean and paint the hub/axle/etc. while
you've got it this far disassembled. I used a combination of rotary and
orbital sanders to remove the pitting from the steering knuckle ball.
It took some time to get it smooth but I think it will help the seals
both seal better and last longer. Also be sure to remove the old inner
axle seal and replace it while the knuckle is open.
Here's a really cheap trick, that can be done anytime, but is easy
while you have the axle torn down. Pull those square plugs on the
knuckle housing (you know the ones you try to pump grease into, not
gear oil, right) and drill and tap a hole for a grease fitting. I
installed a 45°angled grease Zerk in each plug and now its easy to
shoot a little extra grease into the knuckle if needed. With the
crossover steering arms in the way, access to those plugs is limited,
but its easy to pop a grease gun on the Zerk.
Below, you'll find a diagram of the parts assembly for the steering
knuckle, bearings and spindle.
One tip is that the above diagram is missing one crucial component in
the assembly of the spindle. That is the brake backing plate or backing
plate eliminator (a.k.a. spacer). Some folks opt to purchase a pre-made
spacer ring to eliminate the bulky factory backing plate, others just
trim away all but the inner ring of their backing plate to make this
part. But in any even, you need to run something there for proper
assembly of the spindle. So in the above diagram, you see the knuckle,
a gasket, the spindle, another gasket and finally a seal. The
critically important missing component is the backing plate or
eliminator piece. It MUST be placed outside of the
spindle as shown below. The thick ring of the backing plate or
eliminator fills in the recess in the rim of the spindle and provides a
flat surface for the outer hub seal to bolt to. So the order of
assembly is the knuckle -> gasket -> spindle - > backing plate
-> gasket -> seal. Also, the seals may fit best on one side or
the other, so make sure to test the bolt hole alignment before
proceeding. In the far right image below, you can see the completed
assembly. If you leave out the spacer or backing plate the seal will be
deformed into the recess in the spingle flange. And if the spacer is
put between the spindle and knuckle, it will push the hub too far
outwards for the brake caliper to fit properly. One nice upgrade for
the spindle attachment is to install studs into the threaded knuckle
holes. Then it is a much simpler process to slide the various gaskets
and pieces over the studs for assembly. This is 10x easier than trying
to hold 2 paper gaskets, a heavy steel spindle, a bulky brake backing
plate (or eliminator ring) and a seal in place with greasy hands while
trying to get 8 small bolts inserted into deep holes and threads
started in order to hold things in place. So knuckle studs = thumbs UP!
Once the knuckle bearings are installed, insert the inner axle and
birfield into the axle housing. Be careful to support the inner axle
(especially on the long side) as you slip it in past the inner seal. At
the very end, you need to do two tricky movements at once, that is
getting the end of the inner axle into the splines on the differential
carrier and at the same time getting the flats of the birfield joint
past the knuckle bearings. It helps if someone can turn the pinion
flange back and forth while you work the birfield into position. I like
to start with the short side first, since its a lot easier. Once
installed, put on the spindle, brake backing plate and seal and the
retaining bolts (or stud kit).
There seem to be two schools of thought pn how much grease to use, one
is to pack the knuckle full of grease and the other is to just put in
"enough". I like the latter, the birfield itself gets packed
full (that's where all the action is anyway) and then put some around
the knuckle to keep the knuckle bearings lubricated. I like to leave
some air space to allow for expansion when the axle heats up and
prevent the excess grease from being forced out past the felts. In
areas where lots of deep water and mud exist, the full pack might help
to keep water out of the knuckle. But since the areas I wheel are
fairly dry, I prefer to use a minimum amount of grease, since whatever
grease you pack in there while rebuilding will have to be cleaned out
the next time you have to open up the knuckle.
Then proceed to assembling the wheel bearings:
Now there are two schools of thought on properly tightening the wheel
bearings. First is the method documented in the Toyota Factory Service
The second method seems to produce similar results and is a bit more
The idea behind the second method is to ensure the bearing is fully
seated in the grease and then the final torquing sets the pre-load
fairly accurately. I used the second technique on my first rebuild (I
didn't have a spring scale then) and I found the bearings a bit tight.
In fact they seemed to be getting a bit hot on a highway trip to go
wheeling. However, after two days crawling rocks, they seemed to settle
right in. When I got back, I picked up a scale and measured the bearing
drag and both sides were about 8 lbs. total (don't know what the oil
seal drag was and I wasn't about to find out :-), so I guess it worked
In any event, you are on the home stretch and the procedure follows:
Description P/N Qty Cost('98) Comment
Knuckle Rebuild Kit 04434-60015 1 $92 Gaskets and shims
Outer axle oil seal 90311-62001 2 20/pr. Optional
Inner axle oil seal 90311-33085 2 12/pr. Recommended
Steering knuckle Bearing 90366-17001-77 0-4 30/ea Dealer or rebuild kit
Wheel bearing, inner 90368- -77 0-2 /ea Aftermarket cheaper
Wheel bearing, outer 90368-45087-77 0-2 44/ea Aftermarket cheaper
Another nice option, is All pro Offroad's Knuckle Rebuild Kit,
it seems to include all the gaskets, the two different oil seals, a
full set of knuckle bearings, and new "star" washers for the
spindle nuts, in one package. You may need to purchase wheel bearings
and races separately, if needed. Another neat kit All Pro Offroad
offers is a spindle stud kit, which replaces the bolts that hold the
spindle to the knuckle (really fun trying to line up the spindle,
gaskets, oil seals, brake backing plate and get the bolt into the hole
in the knuckle) with easier to use studs and nuts. I'm planning to
install this kit next time the axle is apart.
Tools/supplies you'll also need:
- Expect about 2-2.5 hours per side, longer if cleaning/painting.
If you'd like a second opinion on this project, I researched this
project and found a few good write-ups on the web:
[Last updated: 26.October.2018]