Mustang Monthly
April 2007

How to Install 11-inch Rear Drum Brakes
By: Jim Smart

Photos by: Jim Smart

In our never-ending quest for better performance from our vintage Mustangs, we tend to think about four-barrel carburetors, hotter cams, dual exhausts, and larger engine modifications. But better braking is just as crucial to performance as a more powerful engine. After all, what good is a hotter engine if you can't stop your Mustang?

Front disc brakes have always been a key to improved brake performance. In more recent years, rear disc brakes have become a popular upgrade because they virtually eliminate brake fade under the most demanding conditions. The downside to them is cost -- they can be expensive. Now you can get larger, more powerful rear drum brakes with a super-large 11-inch drum-brake conversion kit. Actually an off-the-shelf Ford drum brake designed for intermediate and large Fords with large-bearing and 9-inch rear axles, the kit also fits 8-inch rearends with small-bearing axles in classic Mustangs.

After spending time with this new drum-brake here's what we know: It installs with great ease, although you may need to tweak or replace the rear-axle brake lines for correct fit. Although it'll fit most 14-inch wheel applications, it won't fit them all. We suggest this kit for 15-inch-and-larger wheel sizes.

When we first heard about this kit, it made us think of the vintage Fairlane station wagon 10X2.5-inch rear drum-brake package upgrade that has long been popular. But the brake shoes with the kit are 2 inches wide, providing more brake-friction surface area. Parking brake performance is also better than most rear disc-brake kits.

The only variation you'll find is brake-line angle. With the large 11-inch brake, it's straight in instead of at an angle. This calls for line modification (bending) or new lines from Classic Tube.

1. Chuck removes the 10-inch drum, then he rattles off four locknuts securing the backing plate.

2. Axle-shaft removal is next. This is a good time to inspect and replace the axle bearing and seal. The axle bearing is pressed on, meaning you need to visit a machine shop with a hydraulic press.

3. The original 10x2-inch drum brake offers less friction-surface area than our larger 11-inch brakes. Chuck will remove the brake and clean the bearing pocket and flange. This rearend is packed with sludge.

4. Brake-line disconnection is next. Chuck uses a tubing wrench to prevent rounding off the fitting. Truthfully, this brake line needs replacement due to rust and corrosion.

5. Chuck removes the brake assembly.

6. Do you see the sludge? When a rearend looks this bad, it's time for a complete rebuild. Sludge indicates extreme heat and poor lubrication, calling for a complete cleaning and a differential rebuild.

7. As you can see, the larger 11-inch, large-bearing drum calls for a larger hub. Because this is impossible with a small-bearing axle, you must use an indexing spacer/adaptor, available from any automotive supply house.

8. Remove the old gasket and debris from the axle flange.

9. Gasket adhesive isn't always necessary, but Chuck likes to use it.

10. Chuck installs the new gasket between the backing plate and axle flange.

11. Also clean the axle-retainer flange.

12. Next, the new 11-inch drum-brake assembly is positioned as shown.

13. Parking-brake cable transfer is easy. To disconnect the cable from the old brake, depress the retainer fingers. The cable attaches here after it penetrates the brake backing plate.

14. Next, install a new gasket and reinstall the axle shaft.

15. Run the locknuts down to 30-40 lb-ft. Chuck snugs them here with an air impact.

16. You're going to need this indexing spacer/adaptor for proper drum alignment. This piece isn't included in the kit, but it's available from most automotive supply stores. Don't operate your Mustang without it.

17. Finally, install the drums.

18. Once the brake line is installed, flush and bleed the brake system.