The Road Vehicles (Construction and Use) Regulations 1986

Vacuum or pressure brake warning devices

17.—(1) Save as provided in paragraph (2), every motor vehicle which is equipped with a braking system which embodies a vacuum or pressure reservoir or reservoirs shall be equipped with a device so placed as to be readily visible to the driver of the vehicle and which is capable of indicating any impending failure of, or deficiency in, the vacuum or pressure system.

(2) The requirement specified in paragraph (1) does not apply in respect of—

(a) a vehicle to which regulation 15 applies, or which complies with the requirements of that regulation, of Community Directive 79/489 or of ECE Regulation 13.03, 13.04 or 13.05;

(b) an agricultural motor vehicle which complies with Community Directive 76/432;

(c) a vehicle with an unladen weight not exceeding 3050 kg propelled by an internal combustion engine, if the vacuum in the reservoir or reservoirs is derived directly from the induction system of the engine, and if, in the event of a failure of, or deficiency in, the vacuum system, the brakes of that braking system are sufficient under the most adverse conditions to bring the vehicle to rest within a reasonable distance; or

(d) a vehicle first used before 1st October 1937.