Overview
The Baer Brakes 4302421B is a black Extreme Plus rear brake kit for GM 1500 trucks and SUVs, built around a 6S monoblock six-piston caliper and a 15-inch two-piece rotor. It fits 1999–2019 Chevrolet Silverado 1500 and GMC Sierra 1500 trucks and 2000–2020 Tahoe and Yukon SUVs, all with rear disc brakes and a manual park brake.
The caliper uses staggered pistons, which reduce uneven pad wear. Its rotor is zinc plated, slotted and drilled with a billet aluminum hat. Wheel fit can vary by wheel style, so use the N228U template with a wheel of 19 inches or larger.
Key features
- One-piece Monoblock 6S caliper with six pistons, made in Phoenix, Az
- Machined from US-sourced 2618 aluminum forging
- Powder coated black finish
- Staggered pistons aimed at reducing uneven pad wear
- Stainless pistons and noise suppression clips
- Dual seals against dust, weather and pressure
- 2-piece slotted, drilled, zinc-plated rotor with a billet aluminum hat
Choosing a rear brake upgrade
Rear disc brake upgrades change how the axle stops under load, so the kit should match how the truck is used. A larger rotor and multi-piston caliper spread heat across more surface, which helps during repeated stops on grades or while towing. On the road, the change is mostly firmer pedal feel and more consistent stopping, though the rest of the brake system still sets the overall balance.
Before buying, check how the axle is already built. Trucks with rear disc brakes and a manual park brake have a different parking setup than drum-equipped models, and the wheel must clear the rotor hat and caliper. Pad compound, brake fluid and the front brakes all affect the result, so review them alongside the kit rather than treating the rear as a standalone upgrade.
After installation, bed in the pads and re-check the caliper bracket bolts after the first few drives. Inspect the rotor surface and hat for cracks or heavy scoring at each tire rotation, and listen for new squeal, which can signal worn clips or pads.
- Rotor hat clearance against the wheel back
- Park brake setup on your model
- Front brake balance with the rear
- Pad compound for your towing load
- Brake fluid condition and age
Specifications
| Brand | Baer Brakes |
|---|---|
| Part number | 4302421B |
| UPC | 844165049784 |
| Caliper | 6S, 1-piece Monoblock, 6-piston, floating, black |
| Rotor outside diameter | 15.0 inch |
| Rotor type | 2-piece, slotted, drilled, zinc plated, vented |
| Rotor material | Iron with aluminum hat |
| Rotor thickness | 1.25 |
| Minimum wheel diameter | 19.0 inch |
| Lug count | 6 lug |
| Wheel bolt pattern | 6×5.50 |
| Brake pad | D1247 type, FMSI D1247 |
| Hardware | NAS high grade stainless, pre-assembled to rotors |
| Hose material | Re-uses OE hoses |
| Template | N228U |
| Emission code | 6 |
| Country of origin | US |
Vehicle fitment
Listed fitment for this kit is 2002–2020 Cadillac Escalade, 2003–2020 Cadillac Escalade ESV, 2002–2013 Cadillac Escalade EXT, 2007–2013 Chevrolet Avalanche, 2002–2006 Chevrolet Avalanche 1500, 1999–2019 Chevrolet Silverado 1500, 2015–2020 Chevrolet Suburban, 2000–2014 Chevrolet Suburban 1500, 2000–2020 Chevrolet Tahoe, 1999–2019 GMC Sierra 1500, 2000–2020 GMC Yukon, 2015–2020 GMC Yukon XL and 2000–2014 GMC Yukon XL 1500.
Heavy-duty 2500 and 3500 pickups and model years after 2020 are not covered by this list. Confirm your vehicle’s year, model and trim before ordering.
Installation notes
Use the N228U template to check clearance against the wheel you plan to run, since the 15-inch rotor sits inside the wheel. The OE hoses and park brake are re-used, so the new caliper connects to existing lines. Support the truck on stands before any rear brake work.
What’s included
The kit includes the black 6S Monoblock rear caliper, the 15-inch 2-piece rotor assembly, and the brackets and hardware, with rotors pre-assembled to NAS stainless hardware.
Not included: lug nuts and front rotor. The park brake is re-used from the OE setup.
