Overview
The Baer Brakes 4302343B SS4 is a black 12 inch rear brake system with a 4-piston S4 caliper, for GM small pattern 10/12 bolt rear axles that use a bearing on axle layout with flush mount bearing housing ends. It is a 5 lug kit for a 5×4.75 and 5×5 bolt circle.
The kit’s one-piece slotted, drilled, zinc plated rotor is designed to work with DR1 or HB100 pads, with FMSI number DR1-C. A backing plate carries the caliper and houses a one-piece park brake shoe assembly.
Key features
- S4 four-piston caliper in black, manufactured in Phoenix, AZ
- CNC machined caliper from forged or billet aluminum with a powder coated finish
- Hard anodized aluminum pistons with stainless steel abutments and noise suppression clips
- Dual seals guarding against dust, weather and pressure
- One-piece slotted, drilled, zinc plated rotor
- Stainless braided brake hoses included
Trail and street use
Rear brakes see different conditions on and off road. Mud, water and grit can collect around the caliper and rotor, while long descents raise heat in the friction surfaces. Rinse the assembly after muddy runs, let it dry, and check that the pads still have even material across their face before the next trip.
On the street, the same parts see frequent light braking and occasional hard stops. Watch for uneven pad wear, heat discoloration on the rotor and any change in pedal height. Those signs usually show up gradually, so a quick check at each oil change helps catch them early.
- Rinse mud and grit from the caliper after trail use
- Look for heat discoloration on the rotor
- Check pad wear at regular intervals
Specifications
| Brand | Baer Brakes |
|---|---|
| Part number | 4302343B |
| UPC | 844165043980 |
| Sold as | Kit |
| Axle | Rear |
| Axle flange | GM small pattern 10/12 bolt with flush mount bearing |
| Axle housing flange type | Hybrid, 3.150 inch bearing on axle, flush mount |
| Wheel bolt pattern | 5×4.75/5×5.00 |
| Lug count | 5 lug |
| Min wheel diameter | 16.0 inch |
| Rotor outside diameter (rear) | 12.0 inch |
| Rotor type | 1-piece, vented |
| Rotor material | Iron |
| Rotor surface | Slotted, drilled and zinc plated |
| Rotor thickness | 1.02 |
| Caliper | S4, 4 pistons, fixed |
| Caliper color | Black |
| Pad FMSI number | DR1-C |
| Hose material | Steel braided, DOT approved |
| Includes park brake | Yes |
| Template | S113E |
| Grade | Performance |
| Emission code | 6 |
| Country of origin | US |
Vehicle fitment
This kit isn’t tied to a listed vehicle. It matches GM small pattern 10/12 bolt rear axle flanges with flush mount bearing housing ends and a 5×4.75/5×5.00 bolt pattern. Confirm those axle specifications with the manufacturer before choosing it.
Axles with different flange styles or bolt patterns are not covered. Confirm your vehicle’s year, model and trim before ordering.
Installation notes
Park brake cables are not included, so decide how the parking brake will be routed before you start. Use the S113E template to confirm wheel clearance at the 16.0 inch minimum diameter. Keep the vehicle supported on stands while you work, and test the pedal before driving.
What’s included
- Black S4 4-piston caliper
- 12.0 inch one-piece slotted, drilled rotor
- Backing plate with one-piece park brake shoe assembly
- Stainless braided brake hoses
Not included: Park brake cables and lug nuts.
