Document ID: chunk:federal_register_of_legislation:F2021C01192:body:0:p15
Version: federal_register_of_legislation:F2021C01192
Segment Type: other
Provision Reference: 
Character Range: 39766–42587

replacement is necessary, is acceptable. In the case of an optical warning, the yellow warning signal specified in paragraph 5.2.21.1.2. below may be used.
5.2.11.2.2. Assessment of the wear condition of the friction surfaces of brake discs or drums may only be performed by direct measurement of the actual component or examination of any brake disc or drum wear indicators, which may necessitate some level of disassembly. Therefore, at the time of type approval, the vehicle manufacturer shall define the following:
(a) The method by which wear of the friction surfaces of drums and discs may be assessed, including the level of disassembly required and the tools and process required to achieve this.
(b) Information defining the maximum acceptable wear limit at the point at which replacement becomes necessary.
 This information shall be made freely available, e.g. vehicle handbook or electronic data record.
5.2.12. In hydraulic-transmission braking systems, the filling ports of the fluid reservoirs shall be readily accessible; in addition, the receptacles containing the reserve fluid shall be so designed and constructed that the level of the reserve fluid can be easily checked without the receptacles having to be opened, and the minimum total reservoir capacity is equivalent to the fluid displacement resulting when all the wheel cylinders or calliper pistons serviced by the reservoirs move from a new lining, fully retracted position to a fully worn, fully applied position. If these latter conditions are not fulfilled, the red warning signal specified in paragraph 5.2.21.1.1. below shall draw the driver's attention to any fall in the level of reserve fluid liable to cause a failure of the braking system.
5.2.13. The type of fluid to be used in hydraulic transmission braking systems shall be identified by the symbol in accordance with Figure 1 or 2 of Standard ISO 9128:2006 and the appropriate DOT marking (e.g. DOT 3). The symbol and the marking shall be affixed in a visible position in indelible form within 100 mm of the filling ports of the fluid reservoirs; additional information may be provided by the manufacturer.
5.2.14.  Warning device
5.2.14.1. Any vehicle fitted with a service brake actuated from an energy reservoir shall, where the prescribed secondary braking performance cannot be obtained by means of this brake without the use of the stored energy, be provided with a warning device, giving an optical or acoustic signal when the stored energy, in any part of the system, falls to a value at which without re-charging of the reservoir and irrespective of the load conditions of the vehicle, it is possible to apply the service brake control a fifth time after four full-stroke actuations and obtain the prescribed secondary braking performance (without faults in the service