The International 1310 front and rear turn signal bulbs both utilize a 198 size bulb specification. The replacement chart covers vehicle production spanning 1971 to 1973.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 198 bulb is the sole bulb type listed across all front and rear turn signal positions for the International 1310, covering model years 1971-1973.
The 198 is an ANSI-standardized bulb recognized in both the United States and Canada, which places it within a regulated specification framework shared across North American markets.
It follows the T5 miniature wedge form factor, a designation that describes a tubular glass envelope approximately 5/8 of an inch wide with a wedge-style base that seats directly into a socket without a separate metal base or pins.
The bulb operates at 12 volts and draws 2 watts, classifying it as a very low-wattage lamp suited to indicator rather than illumination functions.
The 1971 and 1972 entries carry a "Light Duty" qualifier for both front and rear positions, indicating that the 198 bulb fitment applies specifically to the light duty configuration of the International 1310 in those years.
The 1973 entries for both front and rear turn signals list the 198 without a duty-class qualifier, distinguishing that year's fitment notation from the two preceding years.
Because the T5 wedge base is a friction-fit design, socket compatibility is determined by the physical wedge profile rather than a keyed or indexed pin arrangement, making cross-referencing the base type an important step in confirming a replacement fit.
The front and rear turn signal positions share an identical bulb specification in every listed year, meaning a single bulb type serves both locations on the International 1310 throughout the 1971-1973 range covered.