Can I install rear disc brakes?
Unfortunately, no J-body car ever came from the factory with rear disc brakes. However, there are numerous aftermarket kits on the market for this purpose. Several companies make conversion kits, including Stainless Steel Brake Corporation (SSBC) and Baer. One JBO user put together a custom large brake conversion kit using parts from Wilwood. Mantapart offers a 10.5” rear disc brake conversion. Unfortunately, it is not meant for street use as it eliminates the ABS sensors and e-brake (which is too bad, because otherwise it would be a good match for the stock front brakes).
Most of these kits use parts from other cars, in particular the F-body (Camaro/Firebird) and Y-body (Corvette) platforms. The J-body uses the smaller 5x100 bolt pattern, so the rotors are often re-drilled with both patterns in order to fit. These kits all include one key piece of hardware - an adapter plate which bolts to the J-body axle and makes it possible to bolt-on the rear discs from another car.
Several people have successfully duplicated the adapter plates used in the conversion kits, for the do-it-yourselfer who wants to save money by putting together their own kit.
The only downside to these conversion kits, is that the rear discs are mostly 12" in diameter; 2 inches larger than the front brakes. If you don't upgrade the front brakes to 12" or 13" rotors as well, it may look mis-matched. Upgrade kits are also available for the front.
Can I swap the rear disc setup from another vehicle?
Entirely possible, many JBO members have done this. Just remember the key to any conversion is the adapter plate. Pretty much any rear disc brake setup could potentially work, provided that you can fabricate an adapter plate to bolt it onto the J-body rear axle, and adapt the brake and e-brake lines to work. Most aftermarket kits either re-use the factory e-brake cable, or come with new cables.
The most common swap is done using parts from a Dodge Neon, which requires some modification to the mounting bracket. There are usually Group Purchases for these kits, check the Group Purchase forum for more information.
Several JBO members have successfully swapped the independent rear suspension from the N-body, which also includes rear disc brakes. Because the N-body uses the larger 5x115mm bolt pattern, it requires wheels with the larger bolt pattern (or dual bolt patterns).
More reading is available in the Suspension & Brake forum, just search for "Rear Disc" and see what pops up!
