Overview
The Baer Brakes Extreme Plus rear brake system in black, part number 4302270B, is a rear disc brake kit for GM rear ends with the small pattern 10/12 bolt bearing-on-axle housing style and a 5×4.75 or 5×5 inch bolt circle. Baer says its 14 inch rotor and 6-piston 6S caliper suit wheels 18 inch or larger.
Baer designed the backing plate to carry the caliper while housing a one-piece park brake shoe assembly, so the kit provides a rear park brake. The pads are the D1247 type, and the caliper has a black powder coated surface.
Key features
- Monoblock one-piece caliper with six pistons, model 6S, in powder coated black
- Pistons, abutments and noise suppression clips made from stainless steel
- Staggered piston layout to limit uneven pad wear
- Dual seals guard against dust, weather and pressure
- Slotted, drilled and zinc plated 2-piece rotor paired with a billet aluminum hat
- Caliper body CNC machined from 2618 aluminum forging sourced in the US
- Stainless braided hoses and NAS high grade stainless hardware included
Parking brake setup
The park brake shoe in the backing plate gives the rear system its parking function, but the shoe only works when the cables and adjustment are right. Cables are sourced separately with this kit, so choose a set that matches the backing plate and the housing layout. Routing matters, since a cable that binds or rubs will hold the brake unevenly.
Adjustment should be checked during rear service, not only when the parking brake starts to fail. A shoe that has worn unevenly can make the brake feel weak, and a cable that has stretched may leave the shoe dragging. Keep the parking brake in mind alongside the service brakes whenever the rear end is opened.
- Choose cables that match the backplate layout
- Check routing for binding or rubbing
- Adjust the shoe during rear service
Specifications
| Brand | Baer Brakes |
|---|---|
| Part number | 4302270B |
| UPC | 844165043249 |
| Caliper | 6S, 1-piece Monoblock, 6-piston, fixed |
| Caliper color | Black |
| Rotor outside diameter | 14.0 inch |
| Rotor type | 2-piece, slotted, drilled, zinc plated |
| Rotor material | Iron with aluminum hat |
| Rotor thickness | 1.25 |
| Pad type | D1247 (FMSI) |
| Lug count | 5 lug |
| Wheel bolt pattern | 5×4.75 / 5×5.00 inch |
| Axle flange | GM small pattern 10/12 bolt, bearing on axle (Buick/Olds/Pontiac) |
| Housing ends | Non-flush mount |
| Minimum wheel diameter | 18.0 inch |
| Hose material | Stainless steel |
| Template | N110P |
| Park brake | Included |
| Country of origin | US |
Vehicle fitment
No vehicle list is attached to this kit. Baer’s description points to GM rear housings with a small pattern 10/12 bolt bearing-on-axle flange, the Buick, Olds and Pontiac family, and a 5×4.75 or 5×5 inch bolt circle. Measure your housing against those figures and use the N110P template to check clearance on your wheel.
Housings with a different flange style or bolt circle are not covered by this kit. Confirm fit for your vehicle’s year, model and trim before ordering.
Installation notes
Park brake cables must come from another source because the kit leaves them out. Use the N110P template to check clearance against your chosen wheel before mounting, and have a qualified installer complete the brake work.
What’s included
The kit covers the 6S black caliper, the rear rotor set, D1247 pads, the backing plate with its park brake shoe assembly, and stainless braided hoses.
Not included: park brake cables, wheel lug nuts and a front rotor fall outside this package.
