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C-Body Disc Brake Conversion - New Brakes For The NewportA C-body disc brake conversion using parts you can find in the junkyard From the July, 2011 issue of Mopar Muscle By Dave Young Photography by By The Author
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There’s nothing like the road presence, or the ride, of a Mopar C-Body, so when we picked up this Chrysler Newport convertible several months ago we were eager to get it in roadworthy condition. You might remember this car from a recent Hidden Treasures article, after which we got the engine and transmission revived with a bunch of new parts from Rockauto.com. But since the car had been sitting so long, the original drum brakes were deemed untrustworthy, keeping us from taking the big boat for a cruise until we could make some repairs.  1 Most early Mopars came...  1 Most early Mopars came with drum brakes, which can build heat resulting in brake-fade. Unless adjusted perfectly, one will inevitably engage prior to the other, causing the car to Dart to one side and the need to “drive” the car during braking.  2 We love C-Body Mopars,...  2 We love C-Body Mopars, and this month we’ll install disc brakes on the front, new rear brakes, and new tires on our ’69 Chrysler Newport convertible to get it roadworthy.  3 The brakes we’re using...  3 The brakes we’re using are from a ’72 Dodge C-body wagon, but are similar to many C-body brakes used during the late ’60s through the late ’70s. All we really need are the spindles, as the rotors and calipers are still commercially available, but ours came with rebuilt calipers, fresh rotors, pads, and bearings, and even new flexible brake lines. Thanks, Keith. Up front, we’ll upgrade the brakes, replacing the drums with a set of second-hand ’72 C-Body disc brakes we got when we bought the car. In the rear, we’ll simply rebuild the original 11-inch drum brakes with new parts from Rockauto.com, as the C-Body rear brakes are some of the best, and biggest, factory drum brakes available. Combined with a new master cylinder, power brake booster, and a set of new tires from General Tire, our C-Body should be ready to hit the road for some safe cruising. If you’ve never experienced owning, driving, or riding in a Chrysler C-Body, you’ve really missed out on a fun part of our hobby. These cars are large, massive really, and their sheer size gives the driver and passengers the solid reassurance of a sheetmetal cocoon. And this sheetmetal isn’t the kind found on your local Kia dealer’s lot, this stuff is only a gauge or two down from plate steel, the kind used in tanks and battle ships.  4a Using a ball joint separator,...  4a Using a ball joint separator, the spindles can be removed from the upper and lower control arms. Since our disc brakes had been removed with a fire-wrench, we had to do the same in the vice to remove the pieces of control arm from the disc spindles.  4b Using a ball joint separator,...  4b Using a ball joint separator, the spindles can be removed from the upper and lower control arms. Since our disc brakes had been removed with a fire-wrench, we had to do the same in the vice to remove the pieces of control arm from the disc spindles. But while it is encouraging to be surrounded by so much metal, there is a downside, which is extra weight. As a function of their size, some C-Bodys can tip the scales at nearly three tons when fully loaded, creating a sizable mass to bring to a stop in rush-hour traffic. We felt that in the interest of safety, our Newport’s questionable original front drum brakes had to go. From the factory, Mopar cars had some of the best drum brakes for their time, measuring up to 11 inches in diameter. Drum brakes aren’t what we would call a performance braking system, however, adequate for the rear but not for the front of a heavy C-Body. Luckily, we obtained a set of factory disc brake spindles from the previous owner, along with rebuilt calipers, new pads, and freshly cut rotors.  5 With the drum brake spindle...  5 With the drum brake spindle removed and the disc spindle freed from the remaining pieces of the control arms, the disc spindles simply bolt right onto the car’s existing ball joints. Once the fasteners have been tightened, don’t forget to install all the cotter pins.  6 After tightening ball joint...  6 After tightening ball joint nuts and installing the cotter pins, the rotors, brake shoes, and calipers can be reinstalled, completing the front brake conversion. This will make a big difference in the way our Newport drives, ensuring we can stop quickly if someone is texting in front of us.  7 In the rear, we removed...  7 In the rear, we removed the drums and found the brakes to be generally in good condition, though there was evidence of a wheel cylinder leak on one side. We’ll completely rebuild the rear brakes with new brake shoes, rebuilt wheel cylinders, and new hardware from Rockauto.com. He had rebuilt these brakes for a ’72 Dodge station wagon but couldn’t get a title for the car and had to scrap it. Before the car left, he cut the brakes off and saved them for the Newport, including them in the sale to sweeten the deal for us. After installing the disc brakes up front, we’ll rebuild the rear drum brakes, install a new master cylinder with replacement parts from Rockauto.com, then bleed the system completely. We got lucky and got our brake swap parts in the deal with the car, but you can still find C-Bodies to get the required parts from. We aren’t sure why, but there seem to be more C-Body "survivor" cars around, and we still see them in the local junkyards, backyards, and barns around town. These cars have seemed to last longer than other Mopars, likely because they weren’t abused as much, and therefore you can still find donor cars in junkyards to get the front spindles for the disc brake conversion. Any 1969 and up Mopar C-Body with single-piston front disc brakes will work, but stay away from the earlier four-piston calipers. While the four-piston brakes are arguably more efficient, they are also four times as likely to leak, and expensive to re-sleeve if corroded.  8a Having a brake tool certainly...  8a Having a brake tool certainly helps when rebuilding drum brakes...  8b ...But for some operations...  8b ...But for some operations like removing the retaining springs, good old-fashioned channel locks work just as well.  9 We ordered all new Raybestos...  9 We ordered all new Raybestos brake shoes for the rear, as well as new wheel cylinders and hardware. Unlike the local auto parts store that might have the part you need or might not, Rockauto.com gives you multiple choices, allowing you to upgrade where you deem it necessary, like the brakes.  10 After starting our Newport,...  10 After starting our Newport, we noticed that the brake booster wasn’t providing any help. After inspecting the check valve and finding it working properly, we ordered a replacement booster from Rockauto. The new booster is a different design but bolts right into the C-body’s original provisions.  11 The master cylinder is...  11 The master cylinder is the heart of the brake system, so we ordered a new one to install with the rest of our parts. There is much debate about how to bench-bleed the master cylinder, but we still find it best to install lines routing the fluid back into the reservoir, and pump the piston until no more bubbles come out. We do this often enough that we fabricated metal lines for the task, eliminating leaks. In the rear, the C-Body 11-inch drum brakes are adequate for a driver car when used in conjunction with front disc brakes. And while we won’t rule out a rear truck drum or disc conversion for this car sometime in the future, we’ll just rebuild the factory brakes for now and get the car on the road. So long as they are properly proportioned, 11-inch drum brakes are actually not just adequate, but a decent brake for the rear, able to lock up even large tires repeatedly without building excessive heat. New pads, wheel cylinders, and hardware from Rockauto.com will get our rear drums in working order and our car closer to being drivable. Of course these brake upgrades will only work if the tires are sufficient to control the braking action, so we ordered a set of new 15-inch radials from General Tire for the Newport. New tires should always be considered a mandatory upgrade, especially in a case like our car which had been sitting for many years. The 235/75R15 General Grabber A/W radials we chose offer good wet and dry performance, semi-aggressive tread, and 420 treadware, B traction, and B heat ratings. These tires are light-years ahead of the skinny bias-ply tires our car was built with and should greatly enhance the ride and performance of our Newport. We plan to drive this car regularly, and new tires not only perform better, but are more resilient to nails and flat-causing debris, enhancing our car’s reliability. Time to go to work and get our C-body one step closer to some top-down cruising. There’s no doubt that most Mopars are harder and harder to find sitting in scrap yards, or anywhere for that matter, making it difficult to perform repairs with second-hand parts. Fortunately, the exception to this rule seems to be the C-Body. These cars appear to have weathered the storm when compared to more desirable body styles, and we still see them driving around, sitting in storage lots or behind houses, and even showing up in the local junkyards. Since these cars were family cars, many of them were simply abused less and taken care of better than other body styles, then passed down to future generations of drivers. And while C-Bodies may not be as light as other Mopars, we still think they’re some of the coolest cars produced by the Chrysler Corporation. So even if you can’t find the part you need locally, we have several advertisers that deal in pre-owned parts. Just check out their advertisements in Mopar Muscle and help keep C-Bodies on the road! - Editor  12 Before installing the...  12 Before installing the new booster, use either the factory style gaskets or some silicone around the fastener where the booster meets the firewall. This will keep any rainwater leaking down the firewall from coming in the holes and soaking the carpet. Also, you can paint the booster and master cylinder before installation to prevent future corrosion.  13 After installing the booster...  13 After installing the booster and master cylinder, we bled our brake system completely to remove all the air in the system. These brakes should stop our Newport convertible nicely, but will only work as well as the tires will allow.  14 Did we say we needed tires?...  14 Did we say we needed tires? These are two of the four we removed in favor of a set of Grabber A/W radials from General Tire. New tires will greatly enhance our vehicle’s performance and reliability, especially braking.  15 The General Grabber A/W...  15 The General Grabber A/W tires are all-weather tires with semi-aggressive tread and good treadwear, heat, and traction ratings.  15 We chose 235/75R15s as...  15 We chose 235/75R15s as a good replacement for the rollers that were on the car, slightly larger than stock tires to help fill the wheelwells.  16 We installed our wheels...  16 We installed our wheels and tires on the lift but performed the final tightening of the lug nuts with the car on the ground. We’re looking forward to getting our C-body rolling so we can continue fixing it up.  17a Remember the proper tire...  17a Remember the proper tire inflation placard on the doorjamb of an old car might not always be correct when upgrading tires. When this car originally ran a bias-ply tire, it called for 24/26 psi.  17b With a new radial tire,...  17b With a new radial tire, that might be a little low, so going by the tire manufacturer’s recommendations might be safer.  18 Our Newport convertible...  18 Our Newport convertible has come a long way since we picked it up, but it’s still not quite ready for a road trip. Now that the car is drivable, though, we’ll correct a few problems with the interior, seat, and windows, then get her registered for a maiden voyage. Look for future tech articles on this car and let us know what you think at moparmusclemagazine.com.
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