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.
Stainless Steel Brakes continues its dedication to providing true bolt-in brake upgrade kits that are second to none in fit, finish, and performance. We're impressed with the products, and when this project gets back on the road, we're sure we'll be impressed with the performance as well.
C-body fans stay tuned: We'll continue upgrading our land yacht in future issues and will keep you informed of how our upgrades, including this rear brake conversion, help the performance of our car. We couldn't test our rear disc brakes yet since the front suspension and brakes are apart for refurbishing.
The brake shoes and hardware...
The brake shoes and hardware must be removed so the parking brake cable can be disconnected from the old rear brakes. They make a tool to remove the spring retainers, but we've always had better luck using an old-fashioned pair of Channel locks.
Before removing the drum brake...
Before removing the drum brake backing plates, we removed the parking brake cable by squeezing the tabs on the retaining clip and sliding the cable through the hole in the backing plate. The Stainless Steel Brake kit utilizes the factory parking brake cables to actuate the parking brake that's built into its caliper.
With axles, brake shoes, and...
With axles, brake shoes, and hardware removed and the parking brake cable disconnected, the backing plate was removed from the differential housing. We were ready to clean the area and begin installing our disc brakes. Don't throw away the 11-inch drums though, they can be used to upgrade the brakes on another car equipped with 9- or 10-inch drums.
The first step of our installation...
The first step of our installation was to replace the axle end tube studs with the new milled-head bolts provided with the kit...
...These longer fasteners...
...These longer fasteners allow us to mount the brackets, which attach the caliper to the rearend housing.
...These longer fasteners...
...These longer fasteners allow us to mount the brackets, which attach the caliper to the rearend housing.
The axle studs must be changed...
The axle studs must be changed due to the extra space taken up by the rotor that is sandwiched between the wheel and the axle flange. A press can be used for this operation or simply place an old lug nut on the threads and hammer them out like we did.
Tune in next month when we overhaul our front suspension and rebuild our factory front disc brakes. Of course, once our upgrades are complete, we'll put some miles on this cruiser, testing all of our new parts to see if they meet our performance expectations.
The new studs are tapped in...
The new studs are tapped in lightly and will be fully seated when we install the wheel and torque the lugs. We cleaned and packed our axle bearings and slid the axles back in place; then we installed the caliper mounting brackets before tightening the axle retaining nuts.
Next we installed the dust...
Next we installed the dust shield, the rear caliper bracket, and the parking brake cable bracket. All of the parts in our kit fit perfectly; the assembly was really a no-brainer.
The rotors in our kit were...
The rotors in our kit were coated with a light oil to prevent corrosion, so we cleaned them in the parts washer and blew them dry with compressed air before installation.
We also installed our flexible...
We also installed our flexible brake lines onto the calipers before mounting the calipers to the rearend housing.
This bracket holds the parking...
This bracket holds the parking brake cable. We had to install ours reverse of what was shown in the instructions in order for our cable to reach the caliper. We're not sure if the picture in the instructions is backwards, confusing, or if the bracket wouldn't work since we're installing a B-body kit on our C-body. Either way, by simply turning the bracket around, our parking brake cables worked fine.
With the rotors installed...
With the rotors installed on the axles, it was time to test-fit our caliper. Our kit had shims, which can be used to center the caliper over the rotor. This is accomplished by trial and error, mounting the caliper, measuring, shimming, then re-mounting the caliper until it's centered. We had to use all of the shims in our kit, but we did get both calipers centered over the rotors. Once centered, everything was torqued and we moved on to the installation of our brake lines.
The disc brake kit includes...
The disc brake kit includes new steel brake lines for the rearend housing. Bend these to fit by hand before installing them, taking care not to kink them. We used the factory clips on the rearend housing to retain our new brake lines.
Since our factory proportioning...
Since our factory proportioning valve is designed to regulate the brake fluid to drum brakes, we had to install the kit's adjustable proportioning valve in the rear brake system. By bending the rear brake line slightly for clearance and using the supplied short line, we placed ours between the factory proportioning valve and the factory line to the rear brakes. Then we bled the brake system beginning with the wheel furthest from the master cylinder and adjusted the proportioning valve to maximum pressure. So that the rear wheels lock-up in conjunction with the front wheels, we'll do a final adjustment of the rear brakes when the car is back on the road.