8.25 Disc Brake Conversion
Stock 8.25 is drum brakes; conversion to disc brakes uses ZJ/WJ rear caliper bracketry. Major brake performance upgrade for 33"+ tires.
The stock 8.25 in the XJ uses 10" drum brakes. Drums fade under heavy use, fill with mud/water, and are weak with larger tires. Conversion to disc brakes uses the rear disc setup from a 1999-2004 WJ Grand Cherokee or 1993-1998 ZJ.
Conversion methods:
- Pre-made kit (Right Stuff, Reid Racing, Crown Performance): ~$400-600. Includes brackets, rotors, calipers, hoses, parking brake mounting. Best for DIY.
- Junkyard ZJ/WJ rears: cheaper but more piecing-together required. ~$200 for parts.
Procedure:
- Pull drum brake assembly (backing plate, drum, shoes, wheel cylinder).
- Remove axle shafts to access bearing/seal area.
- Bolt on the disc brake bracket (welds onto the axle tube in some kits).
- Install rotor (must match the 5x4.5 bolt pattern).
- Install caliper, brake hose, parking brake cable.
- Bleed brakes.
Key gotcha: parking brake. The XJ stock parking brake uses a drum-style mechanism inside the wheel hub. Disc conversions need either a separate drum-in-disc parking brake (typical) or a cable-actuated caliper.
Proportioning valve: depending on brake master cylinder and proportioning, you may need to adjust front-to-rear bias. Most kits don't require it, but if the rear locks up easily on hard braking, install a proportioning valve.
The disc conversion is a popular upgrade — disc brakes shed mud, run cooler, and stop better with larger tires.
Why it works
- Massively better stopping
- Sheds mud and water
- Less maintenance-intensive than drums
- Required for 35"+ tires
Trade-offs
- Parking brake complexity
- Cost
- May need proportioning adjustment
Tools required
- metric sockets
- torque wrench
- brake bleeding tools
- drill
Parts
| Part | Vendor | Est. price |
|---|---|---|
| Right Stuff XJ disc conversion kit | Right Stuff Detailing | ~$480 |
| Crown Performance XJ disc conv | Crown Performance | ~$520 |
| ZJ/WJ rear disc parts (salvage) | Salvage yard | ~$200 |
Sources
Related
- Ford 8.8 Explorer Rear Axle Swap (Full Guide)
- All Jeep Cherokee XJ guides & tools
- Browse the full DIY database
Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.