(a) each commercial motor auto must have actually brakes adequate to stop and hold the automobile or mix of engine vehicles. Each commercial motor vehicle must fulfill the applicable service, parking, and also emergency brake device requirements noted in this section.

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(b) business brakes -

(1) Hydraulic brake systems. Engine vehicles equipped v hydraulic brake systems and also manufactured ~ above or after ~ September 2, 1983, must, at a minimum, have a company brake system that meets the demands of FMVSS No. 105 in effect on the date of manufacture. Motor vehicles which were not topic to FMVSS No. 105 top top the date of produce must have a service brake mechanism that meets the applicable requirements of §§ 393.42, 393.48, 393.49, 393.51, and 393.52 of this subpart.

(2) air brake systems. Buses, trucks and also truck-tractors equipped with air brake systems and also manufactured on or after ~ March 1, 1975, and also trailers made on or after January 1, 1975, must, in ~ a minimum, have actually a company brake mechanism that meets the demands of FMVSS No. 121 in impact on the date of manufacture. Engine vehicles which were not topic to FMVSS No. 121 top top the day of to produce must have actually a organization brake mechanism that meets the applicable demands of §§ 393.42, 393.48, 393.49, 393.51, and 393.52 of this subpart.

(3) Vacuum brake systems. Motor vehicles equipped through vacuum brake systems must have a service brake device that meets the applicable demands of §§ 393.42, 393.48, 393.49, 393.51, and 393.52 that this subpart.

(4) electrical brake systems. Motor vehicles fitted with electrical brake equipment must have actually a business brake system that meets the applicable needs of §§ 393.42, 393.48, 393.49 and 393.52 the this subpart.

(5) surging brake systems. Motor vehicles equipped with surge brake systems must have a service brake device that meets the applicable needs of §§ 393.42, 393.48, 393.49, and 393.52 the this subpart.

(c) Parking brakes. Every commercial motor vehicle must it is in equipped with a parking brake system that meets the applicable requirements of § 393.41.

(d) Emergency brakes - partial fail of organization brakes -

(1) Hydraulic brake systems. Motor vehicles manufactured on or ~ September 2, 1983, and equipped through a break-up service brake device must, at a minimum, accomplish the partial failure demands of FMVSS No. 105 in effect on the day of manufacture.

(2) waiting brake systems. Buses, trucks and truck tractors manufactured on or ~ March 1, 1975, and trailers produced on or after ~ January 1, 1975, need to be equipped v an emergency brake system which, at a minumum, meets the demands of FMVSS No. 121 in result on the day of manufacture.

(3) Vehicles not topic to FMVSS Nos. 105 and 121 top top the day of manufacture. Buses, trucks and also truck tractors not subject to FMVSS Nos. 105 or 121 top top the day of produce must satisfy the demands of § 393.40(e). Trailers not subject to FMVSS No. 121 at the moment of produce must satisfy the needs of § 393.43.

(e) Emergency brakes, vehicles produced on or after July 1, 1973.

(1) A bus, truck, truck tractor, or a combination of motor vehicles manufactured on or after July 1, 1973, and also not spanned under paragraphs (d)(1) or (d)(2) of this section, must have an emergency brake device which consists of emergency features of the company brake system or an emergency mechanism separate indigenous the organization brake system. The emergency brake device must fulfill the applicable demands of §§ 393.43 and 393.52.

(2) A control whereby the driver applies the emergency brake device must be situated so that the driver can operate the from the typical seating position while limit by any kind of seat belts with which the vehicle is equipped. The emergency brake regulate may be merged with either the company brake control or the parking brake control. However, all three controls might not it is in combined.

(f) Interconnected systems.

(1) If the brake systems forced by § 393.40(a) room interconnected in any kind of way, they should be designed, constructed, and also maintained so that in the occasion of a fail of any part of the operating system of one or more of the systems (except the organization brake actuation pedal or valve), the motor vehicle will have actually operative brakes and, because that vehicles made on or after July 1, 1973, be qualified of meeting the requirements of § 393.52(b).

(2) A motor car to i beg your pardon the demands of FMVSS No. 105 (S5.1.2), handling partial fail of the company brake, applied at the time of to produce meets the needs of § 393.40(f)(1) if the motor auto is maintained in conformity v FMVSS No. 105 and the motor car is qualified of meeting the needs of § 393.52(b), other than in the instance of a structural failure of the brake understand cylinder body.

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(3) A bus is taken into consideration to satisfy the needs of § 393.40(f)(1) if the meets the requirements of § 393.44 and § 393.52(b).