Our '70 Duster originally came with 10-inch drums all around--barely adequate 30 years ago, and downright scary in a car with 350 hp at the rear wheels. Considering that serviceable rear drums are hard to find, and our pre-'73 A-Body had the oddball 5 on 4-inch wheel bolt pattern, a rear brake upgrade was high on our list. |
SSBC's rear disc brake conversion comes as a complete bolt-in kit, including the mounts and hoses, 11-inch vented one-piece rotors, and single-piston calipers with parking brake provisions. The rotors are double-drilled to accept either the stock pre-'73 A-Body's small wheel bolt pattern or the more common 5 on 4-1/2 inch bolt pattern. Swapping to the big bolt pattern requires either custom axle shafts or precision machining modifications of the stockers. Since wheel choice is limited with the small bolt pattern, our plan was to upgrade to the big bolt pattern at the same time as the brake swap. |
In the old days when trucks were for work and musclecars rolled out of Detroit assembly lines, disc brakes were touted as an "upgrade." Salesmen would proudly declare, "...and this baby's got front discs." Today, salesmen key on airbags and cup holders, cars have discs at all four corners, and no one gives it a thought--except those of us riding around in 30-year-old American iron. Disc brakes provide more positive mechanical action, respond linearly to pedal effort, dissipate heat faster, and just plain stop the car more quickly and with fewer quirks than drum brakes. While Mopars could be had with optional front disc brakes, four-wheel discs were the realm of exotica, found only on sportscars like Corvettes or high-end imports such as Aston Martins and Jags. No, it wasn't the territory of Coronets and Dusters.
Making up for the low-grade factory braking hardware is a simple proposition today. The parts to upgrade any corner of a classic Mopar to disc brakes are readily available in kit form. Unlike some of the older conversions, which adapted racing components to Mopar applications, these modern kits utilize durable OE quality components, with such niceties as parking brakes, weather seals, and off-the-shelf availability of replacement pads. Our '70 Duster, sadly, was fitted with 10-inch drums all around. Hard braking provoked poor directional stability, and braking capacity soon degenerated as a result of brake fade--safe enough for low-speed commuting, but not up to the job of halting a high-powered hot rod.
We found that Stainless Steel Brakes Corporation (SSBC) offers bolt-in conversion kits to upgrade drum brakes to discs at either end. The promise of improved braking captivated our interest. We like the idea of retaining our original front spindles for an easy installation, as well as the double-drilled wheel bolt pattern, which would allow an upgrade from the Duster's small bolt pattern.
While adding discs to the front end is a major step forward, we wanted to ditch the puny 10x13/4-inch A-Body rear drums at the same time. We ordered SSBC's basic Mopar disc brake conversion kits for the front and rear of the Duster.
Beyond the basic kit, SSBC offers a number of optional upgrades, including lightweight high-capacity aluminum calipers and slotted rotors. Installing the system proved easy and with no surprises, which is a good thing. A better thing was the improved braking performance. With the stock drums, which we had fully rebuilt, slowing the Duster down at the track from 110 mph was a handful. There was no telling which way it would want to go, but it was certainly not straight.
With four wheel discs, the stops became controlled and predictable. Unlike single-purpose lightweight drag brakes, off the strip, the SSBC kit has the capacity and durability to deliver the goods under "performance street" duty. This was definitely the dope for our dual-purpose Duster.