We've had a couple of close calls in our Dart Sport, and it scared us enough to convince us to do some research about what's available in regards to a rear disc-brake kit. But like you, we were more than a little concerned with what these kits cost. Let's face it, there are a lot of kits out there, and depending on the options you choose, it can get pricey really fast. We actually stumbled across Master Power Brakes' website during our research, and were pleasantly surprised to find a basic rear kit for our Sport that wasn't as expensive as a lot of other kits. The kit from Master Power Brakes included 11-1/8-inch multi-pattern vented rotors (this means you can use them with either 4-inch or 4-1/2-inch bolt pattern wheels), single-piston calipers with pads and integral parking brake, the required brackets, hoses, and cables. It was a complete kit for a fair and economical price. But, if we installed them, would we see a significant improvement in braking distance. The only way to find out was to order the kit and put it to the test. Before we started the install, we took our car to the local industrial-park-straight-stretch-of-road-testing facility after 5:00 pm, and set up a test. We decided that we would get the Sport up to a speed of 60 mph, and when we got to a marked spot on the road where we would start our measuring, we would hit the brakes and see what happened. With our rear drum brakes, the Sport managed a stopping distance of 133 feet and 6 inches. Apparently that was fairly close to where everyone thought it should be, but what would happen when we installed the rear disc brake kit? For those results, you'll have to check out the end of our article.
According to the guys at MP Brakes, if your vehicle was originally equipped with disc/drum brakes, it would have come from the factory with a combination valve that includes an internal metering valve. Metering valve delays the pressure sent to the front calipers, because the springs in the rear drums do not allow the shoes to engage as quickly. This "delay" allows the shoes in the rear drums to engage slightly before the front calipers, thus reducing nose dive. For a disc/disc system, you do not want to use a metering valve. If your car has a combination valve with an internal metering valve, the combination valve should either be replaced with one that does not include a metering valve, or the metering valve could be removed and the opening plugged with a correct size plug.
Editor's note: To remove the metering valve, first remove the cap and plug at the end of the combination valve. After that, simply remove the metering valve, and then reinstall the plug and Loctite it in place.