Since the purpose of our project car, Valiant Effort, is to be a daily driver, we decided that in the interest of safety, she should be treated to a good set of disc brakes up front. Disc brakes weren't available on Valiants in 1967, and they didn't have the 5-on-4 1/2-inch bolt pattern to match the Rallye wheels given to us by a friend (thanks Ron).
After the car is supported by jack stands and the wheels are removed,you must release the tension on the torsion bars. Back out the bolt thatsticks down between the walls of the lower control arm.
When introduced, drum brakes were an almost-sufficient way of stopping a vehicle. But, as cars became heavier and capable of higher speeds, halting that moving mass with drum brakes became more problematic. The difficulty with drum brakes is they tend to "fade" after prolonged use, as in traveling down a long grade or stopping instantaneously, for example. Early types of disc brakes (e.g., Kelsey Hayes) were better than drum brakes--cutting-edge braking technology in their time.
Next, remove the brake assembly by taking out the cotter pins in theupper and lower ball joints, as well as the outer tie-rod end. Thenremove the nuts. We were also planning to replace the brake lines, so wejust cut the old, rusted steel lines. Cutting the lines was easier thanit should have been, so we're glad we planned to change them.
However, in 1973, Chrysler went to the bigger 5-on-4 1/2-inch bolt pattern for their wheel mountings, and since the Valiant now sports the bigger bolt pattern in the rear, the same pattern in front makes sense. We want to avoid the necessity of two spare tires don't we?
While finding a disc-brake setup off of a Duster or Dart may have been possible, a used assembly would have unfortunately cost $200 or more. Factor in the cost of new rotors, calipers, and ball joints (you would change them, right?) and your cost is close to that of a new aftermarket kit. Keep in mind while performing this conversion that the spindle on a disc- brake car is bigger, so you can't just slide a disc rotor over the drum spindle. Let's not even mention where you mount the caliper. Also, the ball joints on pre-'73 cars were smaller than the post-'72 units. The hole for mounting the upper ball in the A-arm is actually larger in post-'72 cars, and therefore, requires a change in the upper control arm and lower ball joint.
We decided to call Master Power Brakes of Mooresville, North Carolina, and see how easy it is to change from drum brakes to disc. The kit arrived in three boxes with all the necessary components, minus the lower ball joints. The instructions say to re-use the old steering arm/lower ball-joint assembly, but the bolt holes are farther apart on the post-'73 models, and the old steering arm/lower ball joint physically will not bolt up to the new disc-brake spindle. Thankfully, a phone call to Just Suspensions of Fairfield, New Jersey, had us working again.
Removing the upper control arms can be a real pain in the neck. Thecaster/camber adjusting bolts (arrow) usually rust to the steel sleeveinside of the control-arm bushing. If you need to cut the bolts, don'tworry--replacements are available from companies like Just Suspension. | 
After we cleaned, primed, and gave the suspension mounting area a coatof primer and black paint, we installed the upper control arm. HINT:Before you install the caster/camber bolts, coat them with antiseize toprevent them from rusting again. | 
After we bolted the caliper bracket to the spindle, we loosely installedthe assembly onto the upper control arm. |
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