Framed Doors and the Fifth-Gen BM Rear Partition Window
Replacing the rear door vent window on this sedan marks a clean departure from earlier Subaru designs that used frameless side windows. On the BM sedan, the stationary glass sits inside a rigid steel frame rather than resting exposed against the weatherstrip when the door opens. It is positioned behind the movable rollup glass in the rear door, separated by a structural vertical division bar. Unlike its platform sibling the Outback, which relies on a fixed quarter panel window glued to the body behind the C-pillar, the Legacy houses its stationary triangle completely inside the door sash.
The glass itself is a curved, solar-controlled piece of tempered safety glass carrying a standard green solar tint across every trim level, from the entry 2.5i and 2.5i Up to the Limited and 3.6R. There are no factory dark privacy variants on standard North American sedans, and the glass contains zero electrical components—no defrost lines, integrated radio antennas, or electronic sensors. The part corresponds to factory catalog numbers 62012AJ21A for the driver-side rear and 62012AJ20A for the passenger side.
Mechanical Fitment Inside the Division Bar
This stationary window does not rely on a bead of polyurethane glue to hold it to the car. Instead, it uses a full perimeter rubber run channel gasket mechanically seated within the division post and the upper door sash. The lower end of this vertical division bar extends deep beneath the exterior belt molding, anchoring into the inner door structure beneath the vapor barrier. Because the glass relies entirely on friction, channel depth, and structural clamping, proper alignment of the division bar is essential to prevent the rollup glass from binding in its tracks.
| Component Details | Legacy Sedan Specifications |
|---|---|
| Glass Position | Rear door stationary partition (no front vent glass) |
| Factory Part Reference | 62012AJ21A (Left) / 62012AJ20A (Right) |
| Mounting Style | Gasket press-fit inside vertical division channel |
| Glass Material | Curved tempered safety glass with green solar tint |
| Integrated Electronics | None (defroster-free, passive glass) |
Any mistake when aligning the vertical guide or resealing the inner plastic door liner creates cabin whistling at highway speeds or allows rainwater to bypass the lower drain holes and seep onto the rear carpets. I protect my work on every installation with a lifetime warranty on my workmanship alongside a one-year warranty on the replacement glass itself. Precision placement of the run channel weatherstrip ensures the passenger compartment remains quiet and dry.
Post-Replacement Inspection Checklist
Once the door trim panel is resecured and the new stationary window is seated, check these specific areas on the vehicle to confirm proper fit and seal integrity:
- Inspect the exterior rubber channel along the top corner of the window frame to verify the gasket is not pinched, folded, or pushed out of its metal track.
- Lower and raise the main rollup door glass fully to confirm smooth travel with no binding or hesitation against the vertical division post.
- Examine the outer lower belt molding where it meets the base of the division bar to ensure it sits flush with the exterior door sheet metal.
- Listen for air leaks or high-pitch wind buffeting along the C-pillar and vertical post while driving at highway speeds.
- Check the bottom edge of the interior door card and the rear floorboard after heavy rain or a car wash to verify moisture is exiting the exterior door drain holes instead of penetrating the cabin vapor barrier.
