Locking of nuts
11.—(1) Subject to paragraph (2), all moving parts of a vehicle and all parts subject to severe vibration which are connected by bolts or studs and nuts shall be fastened by lock nuts or by nuts and efficient spring or lock nut washers or by castellated nuts and split pins or by some other efficient device to prevent their working or coming loose.
(2) The requirements of paragraph (1) above in so far as they relate to brake connections shall not apply in the case of any such vehicle as is mentioned in paragraph (4) of Regulation 9 in the circumstances there mentioned or in paragraph (6) of that Regulation in the circumstances there mentioned.