Match the part number, measurements and connection points that apply to your trailer.
| Hub Face | Measure hub face to hub face. |
|---|---|
| Spring Center | Measure mounting centers and confirm perch configuration. |
| Capacity | Match the required axle rating. |
| Brakes | Confirm brake type and flange configuration. |
AL-KO 12.25" x 3.5" electric brake assembly designed for 9,000 lb, 10,000 lb,and 12,000 lb trailer axle applications. This is the RIGHT (passenger side)configuration and mounts to a 5-bolt brake flange.
Brake assembly is fully pre-assembled on the backing plate and includesshoes, magnet, return springs, and RSA adjuster mechanism.Listing is for ONE complete brake assembly (one wheel).
These 12.25" x 3.5" assemblies are used on heavy-duty 9K–12K axlescommonly found under commercial and equipment trailers.Proper drum width and 5-bolt flange confirmation is critical.
RSA (Reverse Self-Adjusting) systems automatically maintain brakeclearance during operation, reducing service intervals and ensuringconsistent braking performance under heavy loads.Always verify correct side orientation before installation.
| Specification | Detail |
| Brake Type | Electric Drum |
| Brake Size | 12.25" x 3.5" |
| Axle Rating | 9,000 lb / 10,000 lb / 12,000 lb |
| Mounting Pattern | 5 Bolt Flange |
| Adjustment Type | Reverse Self-Adjusting (RSA) |
| Orientation | Right (Passenger Side) |
Verify specifications before installation.
