1961-1971 Sweptline W300 Rear Disc Brake Manual
W300 Single Rear Wheel Disc Brakes
Price: $350 plus shipping and two servicable hubs exchange
Disc brake installation instructions
I have tried to make the installation of this disc brake kit as easy as possible. No grinding, drilling or modification to the knuckle or calipers should be required. We install each set on a test fixture and check them both for proper fit and with a dial indicator for run out (the run out in thousands of an inch is written on the face of each rotor flange.)
Axial (lateral) run out should be .006" or less, radial run out can be as much as .010" without causing problems. Ours are .002" to .005" measured at the outside edge of the rotor ( 12.5" dia ) all of this assumes that the run out on your rotor is 0.000".
Be sure to mount the hub with the lug bolts marked "L" on the left side of the truck and the one with "R" on the right side. Please refer to your particular trucks shop manual for proper procedures for removing and installing original parts i.e. hubs etc.
Additional parts and tools needed
2 ea. 1994 Ford F350 front 4X4 rotors (for single rear wheel truck, not dually)
2 ea. 71-78 GMC 3/4 ton 4X4 caliper (One right and one left)
You will also need a 1/2" socket type allen key for tightening the rotor bolts.
Installation of rear brakes
1. Remove the old hubs, drums, shoes, wheel cylinders and backing plates from the rear axle flanges. It should now look like the Photo below. If your rear axle hasn't been serviced lately this is a good time to do a complete tear down and replace the seals and bad bearings.
2. Install the caliper brackets on the outboard side of the axle flange with the ears pointing rearward. Use the six 1/2" NC X 1 1/2" bolts and spring lock washers provided to install them on the knuckles. Torque bolts to 70 ft. lbs.
3. Place the rotors on the hubs as shown below.
4. Find the ziplock bag of eight 5/8" NF X 1" socket head bolts and use them to fasten the rotors to the flange ( make certain that there are no burrs, dirt or paint between the rotor and the flange). If the rotor that you are installing is a "tight fit" it may be necessary to install the bolts and use them to seat it (tighten the bolts evenly going from one to the other).
Use four bolts per rotor skipping every other bolt hole in the rotor. Use a 1/2" socket type Allen key on a 1/2" drive torque wrench to torque the bolts to 80 foot lbs (Use a wheel inside down on floor to hold the hub and rotor while tightening the rotor bolts).
5. Install new inner hub seals. Pack the bearing cones with high temp. disc brake grease (also the entire interior of the hubs) and install the hubs on the spindles. You should read the appropriate chapter of your trucks maintenance manual for proper installation of the hubs and their nuts.
7. Next install the calipers with their pads in place (make sure that the bleeding nipple is pointing up and the cylinder is to the inside).
8. Insert the caliper pins from the back side through the calipers, then through the 7/16" NF threaded holes in the caliper bracket ears, under the inside pad hooks, through the holes in the outside pads, and finally through the outer caliper holes. After you tighten down the caliper pins against the caliper pin bushings it should look like this. Be careful not to cross thread the caliper pin. Use your fingers to start it as you wiggle the opposite end to get the alignment right.
9. Below is a close up of the caliper pin installation, notice how the inside pad has a hook that rides on top of the pin. Failure to install both of these hooks as shown may allow the pad to drop down out of position resulting in partial or complete brake failure.
Hooking up to your hard lines.
Below is a photo of the rear axle of an M37 with disc brakes installed. Your axle will probably have a similar method of attaching the end of the hard line to the axle. Screw the caliper hose onto the metal line making sure that it will not chafe against anything.
9. Below is a photo of the rear caliper flex hose taken looking down on the caliper cylinder.