A rear disc brake conversion replaces rear drum brakes with disc brakes, usually with a kit that includes caliper brackets, calipers, rotors, pads, hoses and a way to keep a working parking brake. It is a popular upgrade on older trucks and muscle cars because discs shed heat better, are easier to service and resist fade. A successful conversion also needs the right brake balance between front and rear, which may mean changing the proportioning valve or master cylinder.
What a rear disc conversion kit includes
- Caliper brackets that bolt to the axle flange
- Calipers, rotors and pads
- Flexible brake hoses and fittings
- A parking brake solution: integrated caliper parking brake or a drum-in-hat rotor
Kits are specific to the axle and vehicle, such as 1988 to 1998 GM C1500 trucks, so match the kit to your axle.
Things to plan for
| Item | Why it matters |
|---|---|
| Proportioning valve | Rear discs may need different pressure than drums to keep brakes balanced |
| Master cylinder | May need a different bore or residual valves |
| Parking brake | Must still hold the vehicle; check how the kit handles it |
| Wheel clearance | Calipers must clear your wheels |
| ABS | Sensors and tone rings must be retained or relocated |
Drum brake vs disc brake basics
Drum brakes press shoes outward against a spinning drum; they are inexpensive and include a simple parking brake, but they trap heat and need periodic adjustment. Disc brakes squeeze pads against an open rotor, shed heat better and are easier to inspect and service.
Is it worth it?
On vehicles that tow, haul or are driven hard, rear discs reduce fade and make maintenance easier. On a lightly used vehicle with healthy drums, well-adjusted drums with fresh shoes may be all you need.
Do it yourself or shop?
Conversions are within reach of experienced home mechanics, but brakes are safety-critical. If you are not comfortable with bleeding, proportioning and parking brake adjustment, have a shop do it or check the work.
Already have rear discs?
Newer trucks often already have rear discs. On heavy-duty GM trucks, an upgrade to larger calipers is the next step; the SSBC B8 Barbarian rear caliper upgrade kit for 2013 to 2025 GM 2500 and 3500 is $2,031.00. See is a big brake kit worth it?
After the conversion
- Bleed the system fully; see how to bleed brakes.
- Bed in the new pads.
- Test the parking brake on a slope.
- Check for pulling or early rear lockup; see car pulls when braking.
Related
See drilled vs slotted rotors, sticking brake caliper and brake pedal goes to the floor.
Shipping is a flat $80.00 per order to US addresses, with 15-day free returns. Questions? Ask a parts specialist.