Anyone who has owned an '84-'98 3/4- or 1-ton Ford knows they can be quirky. They can come loaded with the burliest components, but the most mundane and seemingly insignificant parts can develop issues and make a good thing seem bad. For example, our '89 F-250 has a really strong 460 and C6 drivetrain that hasn't given us a lick of problems, no matter how much heavy towing we put it through, but most of the electrical switches and motors don't last longer than a gimpy antelope at a watering hole full of hungry lions.
TSM's disc-brake conversion...
TSM's disc-brake conversion kit includes the caliper brackets, spacers, hardware, and rotors. We also had the company ship us new GM calipers with parking brakes (PN 3120), a pair of short cable holders for the e-brake cables (PN 3111), and flexible rubber brake hoses (PN 3701).
A case in point is the Ford Sterling 10.25 rear axle. With a big 10.25-inch ring gear and full-floating 35-spline axleshafts, it's right at home coping with big tires or a heavy trailer. However, we've noticed that the rear drums just don't want to stay in adjustment, despite a full rebuild with new shoes and adjuster hardware. It got so bad that we were contemplating a Dana 70 or GM 14-bolt swap for the rear just so our front tires wouldn't lock up during panic stops when the rear brakes weren't working.
Thankfully, TSM in Castle Rock, Colorado, put the wraps on its new disc-brake conversion kit for the Ford 10.25 axle before we got around to removing our rear axle, taking it to the desert, and blowing holes in it with a Barrett 0.50-cal. The company's kit (PN 2670) includes caliper brackets, spacers, hardware, and 12 3/4-inch vented rotors. You can either supply your own '79-'87 GM 4x4 calipers without parking brake or large GM calipers with parking brake, or buy new ones from TSM. We chose to go with all new parts from TSM. Read on for the install.
 The first step is to chock...  The first step is to chock the front wheels, set the rear axle on jackstands, and remove the rear tires. The drums on the Sterling rear will come off without removing the hubs. Check out the light area on the front shoe (arrow), indicating the shoes have hardly seated to the drums. Despite having more than 20,000 miles on them, the rear brakes have hardly worn at all because they constantly required manual adjustment. |  With the drum removed, you...  With the drum removed, you can remove the axleshaft bolts and remove the axleshaft. Sterlings have a nice rubber O-ring that keeps the shafts from leaking at the hub, but make it a bit difficult to remove the shaft. A few gentle taps with a hammer and brass drift will unseat the O-ring without damage. |  Slide the axleshaft out and...  Slide the axleshaft out and set it aside. Although the Sterling's axleshafts are 1.5-inch, 35-spline at the carrier, they neck down to about 1.36 towards the hub to allow for some torsional twist and flex. The torsional twist helps soak up shock loads that, if transferred directly to the carrier, could damage ring-and-pinion teeth. |
 Whatever you do, please don't...  Whatever you do, please don't use a screwdriver and hammer to remove the hub nut. Special sockets are available at your local auto parts store for around $15. The hub socket is necessary to get the proper bearing preload when reassembling the hub. |  With the hub nut removed,...  With the hub nut removed, carefully slide off the hub assembly, making sure you don't damage the inner grease seal. With the hubs removed, you can pinch off the frame-to-axle brake hose with a pair of Vise-Grips, and disconnect the hard brake line from the wheel cylinders. |  Now that the wheel cylinders...  Now that the wheel cylinders are disconnected, you can disconnect the e-brake cables, remove the four 3/4-inch nuts and bolts that hold the backing plate to the housing, and remove the backing plates from the axles. There's no need to disassemble the shoes and hardware from the backing plate. |