8.25 Disc Brake Conversion

Difficulty 4/56–12 hrs$250–7001997-2001

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

{'title': 'NAXJA disc conversion writeup', 'url': 'https://naxja.org/threads/disc-conversion.901890/'}

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.