Bosch Reflector 1305314931 H4 Headlight Left Mercedes W123 S123 Round NOS OVP
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Bosch reflector insert 1 305 314 931 for the round H4 headlight, left, on the Mercedes-Benz W123/S123.
NOS – uninstalled in the original box · For round H4 headlights · Fits W123 and S123 (up to 09/1982)
Condition of this part
New old stock (NOS) in the original Bosch box with a historical address print (manufactured before 1993). The mirror surface shows no visible corrosion or scratches, only minimal storage marks; the H4 socket is complete with retaining springs. The box itself is dirty and yellowed from age, with a frayed top glue edge.
Function and location
The reflector is the light-shaping heart of the headlight: the H4 dual-filament bulb sits in the socket at the apex of the chromed paraboloid, which focuses the low and high beam. Dulled or hazy reflectors are the most common cause of weak light on classics and a typical failure point at the German MOT (HU). Only the insert is replaced; the housing and lens are retained.
It is installed in the round main headlight at the front left, behind the lens; alignment is done via the adjusting screws of the headlight bowl.
How can you tell a reflector has dulled?
- Low or high beam appears noticeably weaker even though the bulb itself is fine.
- The light cone becomes diffuse or uneven because the mirror surface no longer focuses cleanly.
- The vehicle fails the German MOT (HU) due to insufficient light output.
Compatible vehicles
W123 sedan (up to 09/1982):
- 200
- 200 D
- 230
S123 T-model (up to 09/1982):
- 200 T
- 200 D T
- 230 T
The Bosch part number of this reflector is 1 305 314 931 (left version). For comparison, the counterpart for the right side carries the number 1 305 314 932.
⚠ Important: compare the part number before buying
This reflector is designed exclusively for the round headlight version with an H4 socket. The side assignment (left) follows the dealer catalog listing; the counterpart for the right side carries the number 1 305 314 932.
Does not fit:
- 280 and 280 E (wide-band headlights from the factory)
- Coupe C123
- Vehicles with wide-band/rectangular headlights (from 09/1982 series)
- Vehicles with headlight beam-height adjustment
- Hella headlights
Does this part fit your car? Send us the VIN (chassis number) and model year – we'll check it for free: 0179 8991069 (Mon–Fri 8 am–6 pm) or via our contact form.
FAQ
Do I need to replace the entire headlight?
No, only the reflector insert is replaced. The housing and lens of the existing headlight are retained; the final beam-height adjustment should be carried out by a professional.
Does the reflector also fit square or wide-band headlights?
No, it is designed exclusively for the round headlight version with an H4 socket.
What does NOS mean, and what is the condition of the box?
NOS stands for an unused, new old stock part in the original box. The box itself shows storage marks from age – dirty, yellowed, with a frayed top glue edge – while the part itself is without visible corrosion or scratches.
Related categories: W123
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