Chevrolet C70 Brake Bulb Size

The Chevrolet C70 brake light requires a 1157 bulb size for proper operation and visibility. Data for the specified component covers the range from 1960 through 1988.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	US Type	EU Type	Shop
1979-1988	1157	P21/5W	Check Price
1960-1961	1157	P21/5W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V, 21W/5W.	1157	Check Price
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W	Check Price

Other Locations

Additional Notes

The Chevrolet C70 uses the 1157 bulb across all listed model years for the brake light position, spanning 1960-1961 and 1979-1988.
The 1157 is a dual-filament bulb, meaning it contains two separate filaments within a single glass envelope, allowing it to serve both a high-intensity brake function and a lower-intensity running light function from one unit.
The 1157 operates on a 12-volt electrical system and carries a wattage rating of 21W on the primary filament and 5W on the secondary filament, reflecting the difference in brightness between the brake and running light modes.
The 1157 uses a BAY15d bayonet base, which is an offset dual-contact base. The two contact pins are positioned at different heights, a design that prevents the bulb from being inserted in the wrong orientation.
The 1157 is classified as an ANSI standard bulb recognized in both the United States and Canada, indicating it conforms to a defined set of electrical and physical standards shared across North American markets.
Because the BAY15d base is specific to dual-filament applications, single-filament bayonet bulbs with a BA15s or BA15d base are not interchangeable with the 1157, even if the physical size of the base appears similar.