Ford first started using a disc-braked, open-knuckle
D60 in 1976. The more-desirable high-pinion D60 didn't
come around until mid-year 1977. It was used in the
F-350 and the F-250 with the "SnoFighter" package. This
axle was used until the end of the 1979 model year.
When Ford switched to the new body style in 1980, they
also did away with the Reverse-Cut Dana 60. F-350s were
instead equipped with a leaf-sprung Dana 50 TTB. The
RC D60 returned in 1986. This diff was offset 5" more
toward the driver's side in order to accommodate the
large TTB engine crossmember.
The factory did it this way, why can't I?
Ford always used a leaf-spring suspension on their 1-ton
trucks. They also used a coil-sprung 3-link radius arm
suspension on the 66-79 solid-axle Broncos. Either of
these arrangements will hang your axle. Depending on
what model year the Bronco is, one option might be
easier to install than another.
Which D60 am I looking for?
For a 78-79 Bronco, a 78-79 D60. Weld on c-bushing tabs,
and build a track bar bracket. Reuse your radius arms,
coil spring perches, and bolt it up.
For a 92-96 Bronco, you want a coil-sprung 78-79 D60
too. You can use a 86-97 D60 with coil springs and a
custom radius arm or 5-link suspension. But if you're
building a 5-link, you don't need this FAQ.
For a 80-91 Bronco, a leaf-sprung 86-97 axle can be hung
in a weekend. A coil-sprung 78-79 axle can be done as
easily as for the 92-96 trucks, but the crossmember mods
make it significantly more difficult.
So what's the easiest way to hang my new D60?
For a 78-79 Bronco, leaf springs are not an easy swap.
Due to the arrangement of the steering box, major frame
modifications or +10" of lift are necessary. A 78-79 D60
will easily accept radius arms and coil springs using
66-79 Bronco parts.
The 80-91 Broncos will adapt to a D60 pretty easily.
Aside from notches in the front frame horn to accomodate
the leaf spring shackle, the frame of an 86-97 F-350 is
identical to the frame of an 80-91 Bronco. A 86-97 axle
with a leaf-spring suspension is nearly a bolt-in swap.
A front spring mount needs to be built, and rear spring
mounts and shock towers need to be purchased or salvaged.
Factory steering can also be used.
For a coil sprung, radius arm suspension like the 66-79
Bronco, the 78-79 D60 is much more easily adapted.
However, this axle had the diff housing closer to the
center of the vehicle. While this gives much more room on
the driver's side for mounting radius arms, it also means
that the diff won't clear the engine crossmember. If the
Bronco is going to be lifted 8" or more, this may not be
as much of a consequence. For a rock crawler or trail
truck with a shorter lift and low center of gravity, the
crossmember will need to be hacked and reinforced.
Similarly, the 78-79 D60 can be mounted using leaf
springs, but some crossmember hacking will be necessary.
Because the spring pad spacing is narrower, the springs
will also be closer together, making some additional
fabrication necessary. However, due to the spring perches
being farther from the tire, identical spring travel will
give slightly more flex than a leaf-sprung 86-97 axle.
The 92-96 Bronco has a accordian impact zone built into
the frame forward of the steering box. This section is
designed to crumple in a frontal impact, and is
certainly not strong enough to support a leaf spring
suspension. Like the 80-91 Bronco, the engine
crossmember will require some hacking to clear a 78-79
diff.
So how much has to be fabricated?
For a 78-79 axle with coil springs, c-bushing tabs must
be salvaged or purchased and welded in place. These tabs
will fit snugly against the D60 axle. However, the D44
tube is 1/2" smaller in diameter than the D60 tube. In
order to mate with the radius arms and c-bushing caps,
the tabs must be ground down on the curved side. Spacer
plates can also be made 1/2" thick to go between the
radius arm and the cap. A new hole, drilled 1/2"
forward, will provide a solid mount for the coil spring
perch.
A 80-91 truck with leaf springs and a 86-97 axle will
need spring hangers at a minimum. Going with the factory
arrangement, the frame could be notched and a shackle
bracket and shackle could be bolted in at the frame
horn. Aside from some sawz-all work on the frame, this
is literally a bolt-in swap. However, the forward-mounted
shackle isn't the best arrangement for a wheeler. The
frame can be boxed and pre-80 front shackle brackets can
be bolted in place. The spring shackle is then installed
at the rear using a factory 80-96 rear shackle bracket.
A 78-79 axle under a 80-96 truck will likely take some
crossmember hacking. Be wary of simply removing material
from the crossmember without reinforcing the area. Aside
from supporting the motor and motor mounts, it is the
only crossmember forward of the transmission
crossmember. It can and will tear. An excellent
modification to make would be to remove the bulk of the
crossmember and build a new one that clears both
access to the oil pan and the differential.
|