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pre '75
3/4 Ton Dodge Disk Brake Swap
By Bill Cooke
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If you are running a pre-1975 Dodge W200 Dana
44 front axle then you know how much drum brakes suck! Forget panic stops, even
with a power booster on the truck. They just CAN'T stop a truck like disk brakes
can. Trouble is how do you convert to disks? It's easy, fairly cheap and well
worth the effort. Here's all you need to know.
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The first thing you have to
do is find a Chevy 3/4 ton front axle. It can be a Dana 44 or the later
and more easily had GM 10 bolt front axle. All you will be using from this
donor is the spindles, backing plates, calipers, rotor/hubs and outer axle
shafts. Rotors are dirt cheap to replace so don't worry if they are shot.
The best part about Chevy parts is they are cheap and readily
available! |
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Here's why you need the out
axle stub shafts. The dodge shafts are shorter. How much depends on what
year your truck it. They truck was using mid 50's Dodge spindles and hubs.
That makes the shafts a LOT shorter. The late 60 thru 74 axles have a
shaft that is just about .2" shorter than the Chevy shafts. They are
all 19 spline shafts and you CAN make it work but you are better off
getting the shafts from your donor axle and replacing them. Make sure you
get new u-joints too. This is not where you wan to be skimping on parts! |
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Strip your Dodge axle down to
the knuckle like this. Set the brake backing plate up on the leaf spring
with the brake lines still attached. You'll be transferring the line to
the new calipers in a minute but why make a mess now. Some gear oil might
come out of the axle tube. TO avoid this work on one side at a time and
raise this end higher than the other. That will keep all the fluid inside
and off the ground. |
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Only real difference between
the Dodge and Chevy knuckles is the bolt pattern rotation for the
spindles. The Dodge knuckle is on top. The Chevy is on bottom. You can see
that the Chevy has it's top stud at the 12 o'clock position while the
Dodge is more like 12:45. This will provide one problem later on. Keep
reading. |
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Sorry, no pic here
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It's now time to put it all
back together. Stick the axle shafts back in, put the Chevy spindles on,
the backing plates and torque the nuts down in cross pattern. Then grease
up your new bearings (you did get new bearings, right?) and install them
in your Chevy hubs. Slide the hub/rotor on the spindles and adjust the
spindle nuts back torqueing it to 50 ft. lbs. and then back off 1/4 turn.
Then torque to 35 ft. lbs and back of between 1/4 and 3/8 of a turn, or
until the rotor spins very easily with no wiggle top to bottom. Put the
lock ring in and torque the outer nut to 100 ft. lbs. This will JAM THE
HELL out of the inner nut and will tighten up the bearings. Now install
the locking hubs and bolt the calipers on with your new brake pads (c, mon!
get new pads at least!) |
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Transfer your flexible lines from the old drum
brakes to the new calipers with the banjo fitting pointing up from the
hose as shown. The clearance will be tight but it will clear the axle ears at full
lock steering. You'll also have to rotate the fitting on the axle
tube slightly to make it work. Disk Brake hoses are just a bit longer and
work better so if you are buying new hoses get the '75 and up 1/2 ton or
3/4 ton lines.
The bottom pic is the comparison between
the Dodge lines and stock Chevy lines. The Chevy lines are just WAY too
long to work. |
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Dodge |
Here is the only
draw back to this swap. The Dodge knuckles clock the caliper higher up.
This moves the bleeder screw past the highest point and makes bleeding a
bit more troublesome. One solution, park on a steep hill before bleeding
the brakes. Don't forget to block the tires. The other is to remove the
top caliper mounting bolt and rotate the caliper away from the rotor on
the bottom bolt until the bleeder is straight up. This means no "pump
and dump" bleeding. You will need a power or vacuum bleeder for this
job |
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Chevy |
That's it. It's pretty easy and well worth the
time and money. There is just no excuse for NOT having disk brakes. If not for
yourself, for the poor guy in front of you!
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