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 How do you stop nearly 5,000...  How do you stop nearly 5,000 pounds of C-body with a lead-foot driver at the wheel? Either a brick wall or good brakes will do it. We chose to install good brakes and ordered this rear disc conversion kit from Stainless Steel Brakes. |
 The first step of our project...  The first step of our project was removing all of the caked-on dirt from around the areas where we'll be working. Since we'll replace these brake lines and pull the axles for this project and don't want to contaminate the brake fluid or rearend lube, we used a scraper and spray degreaser to get our work area as clean as possible. |
 Once done, we hosed down all...  Once done, we hosed down all of the fasteners with quality penetrating oil. Royal Purple's Max Film penetrating lubricant works well for this task. |
 The first step to remove the...  The first step to remove the drum brakes was to remove the axles. There are five nuts holding the axle in the rearend housing, which can be removed through an access hole in the axle flange. With the nuts removed, a quick tug broke the seal, and the axle slid out of the housing. |
 The next step was to loosen...  The next step was to loosen the line from the back of the wheel cylinder. By dousing ours liberally with penetrating oil and using the proper line wrench, we were able to loosen ours. Usually these fittings just twist off in a rusty mess, but don't worry, the kit comes with all new rear metal lines, so you can trash the old ones if they're ruined during removal. |
If you're going to propel an object with great mass at any speed, you'd better have a way to stop it. Jet airliners weighing in at nearly one million pounds are equipped with air spoilers, thrust reversers, and multiple disc-braking systems to bring them to a halt. Ocean liners use reversing propellers, strong forward thrusters, and even tugboats to stop their motion.
When determining whether to rebuild the stock binders or to upgrade the brakes on our '70 Chrysler 300, we decided that this car definitely meets the criteria of a boat, and the braking system needs all the help it can get. The problem is C-bodies don't get much aftermarket support, so finding a brake system upgrade kit to fit our car had us scratching our heads. While thumbing through the Stainless Steel Brakes catalog, we were struck with an idea. Since both cars have the 83/4 rearend, why wouldn't the rear disc kit for a B-body work on our C-body? A quick call to Stainless Steel Brakes verified that part number A 155 rear disc conversion kit would fit a C-body, so we placed our order and put the hefty Chrysler on the rack.
Our parts arrived quickly, and we were impressed with their quality. Our kit consisted of two 10.5-inch vented rotors, two cast-iron calipers with single 45mm pistons and built-in parking brake, dust shields, brake lines, adjustable proportioning valve, and all the hardware required to complete the installation. We opted to have our calipers powdercoated black to keep them looking good.
In addition to powdercoating, Stainless Steel Brakes offers several optional upgrades to this kit, including having the rotors slotted, plated, or both. Since this is primarily a street car, and we want it to look as stock as possible, we chose to leave the rotors as provided with the kit. Rear disc brakes weren't an option on this car, but our 300 did come from the factory with front disc brakes, which we are going to rebuild, and the new non-slotted rear rotors have the same appearance as the factory front units.
The new rear discs offer several advantages over the factory drum units. Of course, the biggest advantage disc brakes have over drums is greater stopping power. Even the modest 10.5-inch rotors and fairly small 45mm pistons in the calipers provided with our kit provide far greater stopping power than the 11x2.5-inch drum units they are replacing. The resulting reduced stopping distance, especially in a loaded vehicle, will definitely be noticeable.
Another benefit of this kit is a reduction of both static and rotating weight. The rotors provided with the kit are more than a pound lighter than the drums they're replacing, and the calipers, brackets, and hardware also weigh in at less than the backing plates and associated hardware they're replacing. This is a minor advantage, but an advantage nonetheless.
One of the greatest advantages of disc brakes over drum units is their ability to make repeated stops without the fading associated with drum brakes. Drum brakes work great for one or two hard stops, but the heat trapped inside the drum greatly reduces the efficiency of the brake, and subsequent stops require greater and greater distance. Disc brakes, while not impervious to fade, don't trap heat like the drum units and will provide repeated, consistent stops far longer. Since our car is slated to be a driver and will see lots of street miles, we'll appreciate the added safety and drivability.
The installation of our kit was straightforward and went smoothly. In fact, the only real bummer of the installation was removing about 50 pounds of dirt from the bottom of our Chrysler before starting. Those of you who read our "Rare Finds" column may remember that we found this car in the back woods on a dirt road that was off of another dirt road, which connected to another dirt road about five miles from a paved road, and the car had been driven to and from that location for more than 30 years. Needless to say, this car had a lot of dirt caked on everything underneath, including the rearend and brakes.
Once we had the dirt off and could see what we were working on, it took us about four hours of wrenching to install the kit. The axles had to be pulled and longer wheel studs were installed to accommodate the rotors, but the remainder of the kit bolted right to the axle-tube ends. No major modifications were required, and everything installed as instructed.