Overview
The Baer Brakes SS4 Plus rear brake kit, part number 4302438MG, is a Monster Green rear disc brake system for GM small pattern 10/12 bolt bearing-on-axle rear ends with flush mount bearing housings. It combines a four-piston S4 caliper with a 13 inch, two-piece slotted and drilled rotor on a 5×4.75/5×5.00 bolt pattern.
Baer designed the backing plate to do two jobs: it carries the caliper and houses a modern one-piece park brake shoe assembly. The kit suits owners who want a performance-grade rear brake upgrade with a color-matched caliper, on axles where the wheels are 17 inch or larger.
Key features
- Four-piston S4 caliper with hard anodized aluminum pistons and stainless steel abutments
- Two-piece slotted, drilled, zinc-plated rotor with a billet aluminum hat
- Dual seals that guard against dust, weather and pressure
- Powder coated Monster Green caliper finish
- Rotors pre-assembled with NAS high grade stainless hardware
- Steel braided brake hoses and hardware included
- Caliper manufactured in Phoenix, Arizona, with CNC machined forged or billet aluminum parts made from US sourced stock
Before you buy
Rear disc brake kits are chosen by axle type first. Before ordering, measure the axle flange and confirm the bolt pattern, since the bearing housing style determines how the backing plate seats. Wheel clearance matters just as much. A larger rotor and caliper can reduce room behind the spokes, so test the assembly against the wheels you intend to run before the final bolt-up.
Brake fluid, lines and the master cylinder should be reviewed when the rear brakes change. A stronger rear setup can shift braking toward the back, so many owners pair a rear upgrade with fresh pads and clean fluid. Check the parking brake function after installation, because the shoe assembly and cable adjustment both affect how well the lever holds.
- Confirm axle flange and bolt pattern before buying
- Test wheel clearance with a template before final assembly
- Plan park brake cables and fluid lines as separate purchases
Specifications
| Brand | Baer Brakes |
|---|---|
| Part number | 4302438MG |
| UPC | 90127952740 |
| Sold as | Kit |
| Caliper | S4, four-piston, fixed |
| Caliper color | Monster Green |
| Rotor type | 2-piece, vented, slotted, drilled, zinc plated |
| Rotor outside diameter | 13.0 inch |
| Rotor thickness | 0.81 |
| Minimum wheel diameter | 17.0 inch |
| Axle flange | GM small pattern 10/12 bolt with flush mount bearing |
| Wheel bolt pattern | 5×4.75/5×5.00 |
| Lug count | 5 lug |
| Brake pad FMSI number | DR1-C |
| Brake hose | Steel braided, DOT approved |
| Template | S135H |
| Emission code | 6 |
| Country of origin | USA |
Vehicle fitment
It fits GM small pattern 10/12 bolt bearing-on-axle rear ends with flush mount bearing housings. Match your axle flange and wheel pattern before ordering.
Installation notes
The rotors arrive pre-assembled with stainless hardware, so there is no separate hat to build before mounting. The park brake shoe assembly sits inside the backing plate, so the parking function comes with the caliper mount. Park brake cables are not included. Use the S135H template against a 17 inch or larger wheel to check clearance, because Baer cannot guarantee fit with every wheel style.
What’s included
The kit includes the S4 caliper in Monster Green, the 13 inch two-piece rotor assembly, the backing plate with its park brake shoe assembly, and stainless braided hoses with hardware.
Not included: Park brake cables.
