Section 26521 Of Article 4. Vacuum Brakes From California Vehicle Code >> Division 12. >> Chapter 3. >> Article 4.
26521
. Motor vehicles required to be equipped with power brakes and
equipped with vacuum or vacuum-assisted brakes and motor vehicles
used to tow vehicles equipped with vacuum brakes or vacuum-assisted
brakes shall be equipped with either an audible or visible warning
signal to indicate readily to the driver when the vacuum drops to
eight inches of mercury and less. A vacuum gauge shall not be deemed
to meet this requirement.
This section shall not apply to a two-axle motor truck operated
singly nor to any motor vehicle manufactured prior to 1964.