XJ ran rear drums all years. ZJ disc or aftermarket kit (Right Stuff, Vanco, ECGS) bolts to D35 or 8.25. Big improvement for lifted rigs on bigger tires.
Every factory XJ came with rear drum brakes which become inadequate with larger tires and trail loads. Conversion to rear disc is a popular upgrade. Three main paths. 1) ZJ (1993-1998 Grand Cherokee) rear disc swap: source ZJ rear calipers, brackets, parking brake cables, and rotors from a junkyard; the brackets bolt to the Dana 44A or to the Chrysler 8.25 with minor mods. Total cost $100-300 if scavenging. 2) Aftermarket kit such as Right Stuff Detroit ($400-700) or Vanco Big Brake ($500-1000) provides everything new with proper hardware and detailed instructions. 3) ECGS or TeraFlex full conversion kits ($800-1200) include caliper, rotor, parking brake assembly and adapter bracket. Critical: rebalance brake bias with a Wilwood adjustable proportioning valve or a ZJ master cylinder swap to avoid premature rear lockup. Also reset the parking brake cable length. Some kits work only with specific 8.25 or D35 housings - measure carefully.
| Part | Vendor | Est. price |
|---|---|---|
| Right Stuff rear disc kit | Right Stuff | ~$600 |
| Wilwood proportioning valve | Summit | ~$50 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.