Disc Brakes
Now for the fun part, the disc brake conversion. It's easy to relocate shock mounts and spring perches, the fun comes when trying to convert an odd-ball, 30 year old axle to new technology (disc brakes).
Rotors - The rotors from my TSM kit fit over the axle shaft flange. This is good news because the diameter of the
hole in the rotor often differs from the flange on the outside of the axle shaft.
So the rotors fit!
Backing Plate - One of the important things to remember when doing a make-shift rear disc
kit is where everything was when you started. For example, this axle has the bolts
going through axle tube flange, then the backing plate is sandwiched between the
tube flange and the retainer-oil seal plate to proper seat the bearings on the
axle shaft to the race in the tube. When you replace the drums you have to eliminate
the backing plate. So I cut out a "spacer" from the backing plate to properly
press the bearing when this is all said and done. If this doesn't make sense,
I'll post some pics to show it clearly.
Caliper Bracket - This is the tricky part of the whole conversion. This is because this axle
had rather large drum brakes and there was a large space between the axle shaft
flange and the flange on the axle tube flange. When you put the rotor on the outside
of the axle shaft, there is about a 1.5" gab between the inside of the rotor and the axle shaft flange. In the dana 44 disc conversions I have done, the caliper bracket bolts to the inside of
the axle flange but with this axle, that is not possible because the rotor is
spaced too far away for the caliper and pads. In addition, this axle has a 6 bolt
set up and not the 4 bolts on the Dana 44 axle tube flange. BUT! the good news is that the 6 bolt pattern is the same as Dana 44 front axles at the
splindle!
I just so happen to have a left over set from my front 44 swap a few years ago
(c:
So, what I did was "notch" the front caliper brackets to go around the axle shaft
and to bolt them to the retainer-oil seal plate.
Here you can see how the set up bolts up. From the axle tube flange, you first
have the backing plate spacer cut out, then the retaining-oil flange and the caliper
bracket is the last to be bolted to sandwich everything together.
Caliper & Pads - Because I have to use the front caliper brackets, I then have to use the larger
GM calipers and pads. The other dana 44 disc conversions used the smaller caddy calipers (with the ebrake on the rear calipers). So that means no ebrake unless I can figure out something else......
The problem with this set up is that I'm using caliper brackets from an 8 lug
J20. Both the brackets and calipers rub the 15" rims so it requires some grinding
for clearance. The pic above shows everything installed and the grinding done to the bracket and caliper
to clear my 15x12 wheels.
Lines and Hoses - I will use the caddy front hoses that I had on the scout axle and run a new hard line to the driverside hose. I will use the same "T" brake hose from the frame to the axle tube with the 2" spacer.