Killer Kong Project Update: Speedway Motors’ Speedy Disc Brake Swap

We take a lot of today’s modern conveniences for grated. The creature comforts, safety features, improvements to design and ride of today’s cars are a culmination of the past 100 years, providing us a time in which even the very lowliest of new cars are lightyears ahead of the top-of-the-line luxury machine from 25 years ago.

Seat belts for every sitting position only became a “standard feature” in 1957. Before then, they were an optional part of interior or trim packages. Collapsible steering columns finally replaced their deadly solid-shaft predecessors nearly a decade later. Headrests and shoulder harnesses followed soon after violent crash testing video scared politicians into passing laws.

Pay no attention to the nice QA1 double-adjustable shocks, it's only for contrast. Notice that our upper and lower control arms were in some serious need of TLC - as well as our ball joints - before we could upgrade our front brakes.

Factory-standard disc brakes didn’t become the bare minimum for decades later. While few cars came equipped with front drums during this time, rear drums were common on passenger cars and pickup trucks well into the 1980s.

Considering that “juice” or hydraulic brakes commonly replaced mechanical brakes by the late 1920’s, the evolutionary steps to standardized disc brakes has been a long one.

Today, disc brakes equipped with ABS are as common as the DOT fluid that fills their lines. In fact, even milquetoast four-door family sedans feature ventilated and slotted rotors, brake ducts and even multi-piston calipers.

It’s a terrifying thought to us diehard car lovers that a brand-new Toyota Camary could perform admirably among a field of 1950s road racers, but that’s the evolution of the automobile. Yesterday’s race-only gear is tomorrow’s standard equipment.

Kong’s Caliper Quandary

Undoubtedly, you’ve been following the development of our venerable ’69 Dodge Charger, Killer Kong. While looking deceptively ready to run, we’re still quite a ways away from firing up good ol’ ‘Kong and getting the mighty Mopar out on the streets.

Key to this is ensuring that our hefty B-Body Dodge is able to put on the skids whether between red lights or after passing through the traps at 125 miles per hour.

We’ve joked before that our Charger came from the factory with everything it needed to be an R/T but the 440 RB motor and the R/T tags. Well, that’s not entirely true. Part and parcel with the Rapid Transit package was a pair of four-piston calipers clamping a set of ventilated two-piece motors, as well as a pair of large 11-inch diameter drums out back.

We scored an old junkyard '74 Plymouth Valiant front disc brake setup ages ago. Unfortunately, we were pretty cheap back then, and never even bothered to swap out the factory bearings. Yeah, that's pretty cheap. Since we were going to swap out our junkyard front end, we figured it was a good time to clean up our factory control arms.

We pulled our front end setup to give our upper A-arm and lower control arm a much-needed refresh. We even swapped out the lower control arm bumper bushing, although looking back, we regret not boxing it in. Look's like we'll be backtracking a little at a later date. We hit up Just Suspension for new bushings, bearings, tie-rods, and upper and lower ball joints.

Although compared to today’s cars, they might appear antiquated and almost ancient, Chryslers were noted for their responsive and comfortable ride and apt braking. Starting with Lockheed’s first hydraulic brake system, Chryslers were the first to feature fluid brakes on passenger vehicles, and were one of the first domestic automakers to standardize front disc brakes a half century later.

This isn't the first time you've seen 'Kong up in the air, and it definitely won't be the last. We routed all of our replacement mild steel lines - from Year One - through all the factory spots, even going so far as to use replacement factory-style clips and hangers.

For 1969, the Dodge Charger and its fellow intermediate-sized siblings the Coronet, Super Bee, Road Runner, GTX and Satellite, all were offered with the same front disc brakes as part of a special R/T handling suspension package featuring heavy duty torsion bars, shocks, rear springs and sway bar, in addition to a set of Bendix four-piston calipers grinding a set of two-piece rotor/hub assemblies to a halt.

While an improvement over the standard front drums, the two-piece rotors were known to warp and distort during hard braking, causing severe brake pulsing and vibration. By the mid-1970s, Chrysler replaced the two-piece rotors with front unicast rotors (one-piece hub and rotor) which improved the warping concern, but encountered heat dissipation issues, leading to the 11.75-inch unicast police rotors with cast-in reinforcing ribs in 1976.

The rotors weren’t the only the parts to get an improvement during the 1970s. While modern technology would make the multi-piston caliper the choice of performance brakes, the original Bendix four-piston calipers from the ’66-to-’69 cars were replaced by a single-piston Kelsey-Hayes pin-type on the 1970 models.

The factory spindle (or steering knuckle, as many refer to it) bolts to the lower control arm, the bolts torqued to 120 ft. lbs. These will be a bear to break free, so be prepared to put some leverage on it. Unless you're using a ball joint splitter, using a common pickle fork will almost always tear the dust boot on the upper ball joint.

Speedway Motors' drum brake-replacement disc brake kit incorporates the improvements to Chrysler's unicast hub/rotor assembly, with reinforcement veins inside of the hub, a clean, machined surface, and a single-piston caliper that accepts factory Chrysler brake pads for future maintenance.

Given the few production cars equipped with the limited four-year run, finding an original Bendix-style disc brake setup was almost impossible. Years earlier we learned that B-Bodies from the earlier dates equipped with drum brakes could swap their steering knuckle (i.e. spindle) with any ’73-’74 E-Body or disc brake-equipped A-Bodies from 1973-through-1976.

We stumbled across a ’74 Valiant in our local salvage yard with a decent set of discs that we took home and cleaned up. The only trick was reversing their location – from driver side to passenger side – due to the steering end linkage.

Speedy Bill Swoops In To The Rescue

We just haven't figured out an easier - or cleaner - way to pack bearings than the same way your grandfather packed bearings.

We understand that not everybody has access to junkyards rife with old mid-’70s A-Bodies, so we sought out to find a kit that would meet the needs of fellow Mopar enthusiasts looking for a proper replacement to a factory drum brake B-Body.

Not surprising to anyone who knows ’em, Speedway Motors offers a complete disc brake kit for 1962-1972 B-Body and 1970-1974 E-Body Mopars. Completing the package was the new cast 11″ outside diameter rotors, spindles, calipers, brackets, pads, bearings, seals, dust caps, hoses and hardware.

While we were at it, we figured on replacing the old and bent brake lines, as years of disuse had clogged them with grime and corrosion. We first turned to Year One for our brake lines, distribution blocks and master cylinder.

Offering much more than just cosmetic replacement parts, Year One has been providing muscle car enthusiasts with nearly every single thing imaginable for their classic since 1981. When our box showed from Year One’s Braselton, Georgia headquarters, we had all the clips, brackets and retainers needed to fully reassemble a good-as-new factory-style brake system.

Besides the high-temp bearing grease, the Speedway Motors disc brake swap kit comes with everything you'll need to swap out your brakes in a manner of hours. Starting with the inner bearing, we packed that with grease until it seeped out of every orifice. Sandwiched between a new billet race and the rubberized seal, we moved on and packed the front bearing.

Not too bad for a Saturday. With the help of a friend, we pulled Killer Kong's front brakes and front suspension, cleaned up our control arms, replaced the ball joints, bolted on a brand-new fresh set of disc brakes, routed some steel brake lines, plumbed our entire brake system, bolted up a master cylinder (with an adapter plate), and bled the whole system. Too bad 'Kong doesn't run yet, or we'd drive it to the burger stand that night.

Back when we were prepping ‘Kong for paint, we pulled most of the original brake lines, metering blocks and master cylinder. Our Charger was an original power drum brake car, but we had ditch the brake booster ages ago. Since our new larger 11-inch drums were provided by Currie Enterprises when we rebuilt our junkyard Dana 60 rear, we didn’t have to worry about rebuilding some worn out and gutted factory drums.

With all new brakes on our ’69 Charger we’re only that much closer to getting ‘Kong out on the street.

Getting Our Hands Dirty

Once again, we hefted ‘Kong up on the jackstands and pulled the front Weld skinnies. The original Ma’ Mopar single piston caliper was held on with twin pins which came out easy enough. We pulled the old dust cap, pulling and dropping the castle nut, retainer and bearing into a small cup of parts cleaner. We’re not into throwing much away, so we opted to clean and stow away our current brake setup.

While there are bearing splitter tools that are far better at separating ball joints, they’re also pretty expensive…particularly when compared to our trusty pickle fork. Sure, we tore one or two boots in the process, but since our boots needed changing anyways, we didn’t feel too bad because we had gone to Just Suspension for our ball joints, boots and tie rods. Our factory spindles popped off as soon as we pulled all the cotter pins and broke all the castle nuts loose.

Installing our new steering knuckle was as easy as removing the old one - even easier with our new Just Suspension ball joints and cleaned up control arms. We made sure to apply a little thread locking compound to the original ball joint bolts before re-torquing them back to 120 ft. lbs. We also torqued down the caliper bracket bolts to 95 ft. lbs. All buttoned up, we installed our brake pads and slid on the caliper.

Swapping out the spindles with the new Speedway Motors pieces was a synch. Speedway provided all new cotter pins, roller bearings, races and seals. Starting with our new single-piece hubs, we prepacked our inner bearing thoroughly before sandwiching it between the race and the seal, tapping it down with a rubber mallet.

With the new steering knuckle attached to our newly refreshed upper and lower control arms, we slid the new hub over the machined spindle, but not before installing the dust shield. These stamped pieces have a nice chamfered edge so you won’t have to worry about slicing your hand open on ’em later.

For ease of installation, its common to install the flex line to the caliper prior to attaching it to the rotor. Speedway Motors includes the copper gaskets which will seal the threaded brake line to the caliper, so make sure not to forget them!

Holding the hub in place, we slid the freshly packed outer bearing in between the inner race, outer washer, and nut. With that, we applied a healthy dollop of bearing grease over the spindle end and we closed the cap over the hub bearing. We then threaded our new Speedway-supplied brake flexline’s banjo fitting to the single-piston caliper and C-clipped the female end to the framerail perch.

Get In Line You Brake Lines!

With our new front brakes installed, we went about plumbing the rest of Killer Kong. Year One offers every inch of hard line you’ll need to replumb your classic car. For our application, we went with Year One’s standard factory diameter mild hard lines which come pre-measured, pre-bent and already flanged with the threaded male end already attached. Since they’re pretty long, Year One ships them with a gentle bend in the middle that is easily bent back in shape.

We were looking to recreate our factory drum brake plumbing configuration, as the single-piston calipers are designed to be a direct replacement for the front drums. This meant we didn’t require the use of a portioning valve, as disc brake-optioned cars came from the factory.

Considering this, we saved some moolah by cleaning up our original metering block with some Scotch Brite until it looked brand new. This simple setup allowed us an ever easier job of routing our new brake lines – particularly as we directly replaced the factory line with our new Year One tubing.

With everything installed but our master cylinder, fabricated a small block-off plate to cover the larger hole left by not running the power brake booster.

Since Speedway's disc brake conversion kit is designed to exactly replace your Mopar B-Body's front drum brakes, its designed to work with a factory drum brake line setup. That's why we simply cleaned up our original metering block and threaded in our new Year One brake lines.

Thankfully, this didn’t relocate our master cylinder’s position, so our brake pedal pushrod didn’t require any modification. It’s commonly understood that all master cylinders must be “bench bled,” this isn’t as literal as it sounds.

In a great article by Mopar Action’s Richard Ehrenberg, he suggests fabricating a set of homemade bleeder tubes. These allow you to forgo the old – although, far easier in our opinion – way by hooking everything up and chasing the air out of the system at each fitting with the bleeder screw.

This way requires the help of a friend and will likely cause a bit of a mess if you’re not careful, but you’ll know you’ve chased all the air out of the system.

With all new brakes on our ’69 Charger we’re only that much closer to getting ‘Kong out on the street. We’re going to button up the interior in the next couple of installments then we’re going to get crackin’ on our wicked stroker Wedge powerplant. Stay tuned!

About the author

Kevin Shaw

Kevin Shaw is a self-proclaimed "muscle car purist," preferring solid-lifter camshafts and mechanical double-pumpers over computer-controlled fuel injection and force-feeding power-adders. If you like dirt-under-your-fingernails tech and real street driven content, this is your guy.
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