If
you like to push your rig to its limits, you're probably familiar with the
sight at right.
You've probably just thought: "Yeah, that's what happens when you
push things too hard".
Well, you may be surprised to find out, sheer abuse is not always
the culprit here.
Your
stock Dana 35 axle shafts are equipped from the factory with Spicer 5-297X
u-joints, and are retained by small half-round C-clips in the yoke. When
pushed real hard with locking differentials & oversized tires, the
joint's bearing caps often will try to 'spin' in the yoke as the joint
operates. As it rotates, it often "spits" off it's clip and then
the cap is free to walk out of the yoke, departing from the axle (if it doesn't
get crushed by the balljoint stud first). The u-joint trunnion then rips
apart the axle yokes, causing a catastrophic failure like above (you can
be sure this is what happened if you find the joint's cross (main body) is
not broken).
A full-round clip that fully encircles the joint's bearing cap can quickly
put a halt to this type of failure.
Unfortunately, just putting a
full-round snapring on the cap isn't possible to do without a bit of work
to the axle yoke. Read on for how to make this possible (If you have a
swapped-in Dana 44 axle, this modification will still provide the same
benefits, as the joints are identical :-) .
Start by removing the clips and pressing out the old joint (a shop press
makes real quick work of pressing them out (<even a homemade one lol).
You can also purchase or rent a C-frame press (balljoint press) from some
retailers that will do the same job. It basically looks like a large
C-clamp, but has a receiving cup on one side for the bearing cap to press
into.
If the joint is stubborn from rust, a good smack with a hammer while it's
under pressure will usually pop it free.
Here
you can see why a round clip won't fit, this shoulder on the yoke is in
the way. This is primarily to blame for the c-clips coming off... As
the cap spins, the clip wants to spin with it. The end of the clip hits
against the shoulder, and basically ejects itself.
This shoulder has to be removed from the yoke.
Using an angle grinder, carefully grind down the shoulder, being careful
not to grind below the level of the flat area on the yoke, until it is
almost even.
Next,
using
a Dremel (or similar) hi-speed rotary tool, carefully dress up the yoke
until a 1-3/16", external-type snapring sits perfectly flat on the yoke.
While it is possible to do this with the angle grinder alone, I like the precision afforded here so that it's much less likely you'll whip
off too much material at once and weaken (or ruin) the shaft.
You also want to make sure there are no high spots left, as this can
create a stress point which could cause the cap to crack around the clip
groove.
Keep checking your progress until you've determined that the clip sits
down flat.
Here is the round snapring (aka,
retaining ring) shown next to the original c-clip.
They can sometimes be found at
auto parts stores, as well as some hardware stores.
Shown
is a new Spicer 5-760X replacement joint next to the old 5-297X. These
joints are an updated design and have a cold-forged cross which has
repeatedly been shown to be much stronger than the 297's hot-forged cross,
with a much longer fatigue life. This should help to further put the
brakes on broken u-joints.
I have found this cross is next to impossible to break, the needle
bearings in the caps generally will crush and disintegrate before the
cross itself fails (that is if the splined end of the shaft doesn't twist off first).
Note the circular forging on it vs. the smooth center on the 297. These
joints are currently priced around $25 or so each. Well worth the $$
over cheap "house" brand joints (which still use hot-forged
parts)
Position
the snaprings on the joint and install it into the axle yoke. Install the bearing cap over the
trunnion, being
careful none of the needle bearings fall out of place, and press the joint
into place.
With
the joint fully in place, use a set of snapring pliers to position the
rings into their grooves. Using pliers with a 45° angled tip can make
things a bit easier in some cases.
Repeat for the opposite shaft.
Your shaft is now ready to put the power to the ground!
With the full-round snapring clips, the caps can spin in the yoke all they
want, and won't ever come out.
While you have the grinder out, give the TTB
center slip shaft a bit more clearance on it's yoke as well.
I have found that this joint with it's limited movement, can be prone to
binding (and subsequent failure) on suspensions that have been modified
for large amounts of travel.
A small amount of clearancing as shown below at right can help to
eliminate failures at this joint as well.
Whatever you do though, never grind on the ENDS of the yoke to gain
clearance (the loop part). This will weaken it..
Below shows the additional operating angle that can be obtained (top
shaft) next
to an unmodified shaft (bottom). While it may not look like a whole lot,
it adds up to having several more inches of available bind-free suspension
travel, and can easily make the difference between busting, and flogging
it with ease.
The simple modification of
adding round clips to the caps (combined with using the 5-760X joint) can
add 10-15% or more durability to your stock shafts (to put that into a
better perspective, that's about the difference in torque your shafts see when
running 35" tires vs. 31" tires). This could be enough to
eliminate the need for costly aftermarket alloy shafts in some cases.
Some guys will often just tack-weld their caps to the axle yoke. While
this effectively accomplishes the same thing (and is much quicker/easier
to do, if you have a welder), you are no longer left with the option of servicing or replacing
the joint in the future. The snaprings will not hinder serviceability of
the shafts should the need arise. ~TRS
