Commercial Vehicle Safety Alliance

Date d’inscription	9 juin 2017
Numéro de l’enjeu	17-030-VEH
Nom	john behrens
Organisme	hope towing
Adresse	1060-5th avehope, bc, v0x1l0United StatesVoir sur la carte (s’ouvre dans un nouvel onglet)
Téléphone	6047500238
Télécopieur	(604) 869-0049
Courriel	[email protected]
Comité	Comité des véhicules
État	Fermé
Résumé de l’enjeu	J'aimerais consulter un rapport de sécurité concernant les disques de frein fissurés et leur non-conformité lors des contrôle routier. Ce rapport préciserait les critères de réduction de l'efficacité des disques, notamment si la réduction de 20 % de la capacité de freinage s'applique. Si tel est le cas, sur un disque ventilé, chaque surface serait prise en compte dans le calcul. Il est possible de commander des disques avec des trous et des rainures usinés sur la surface d'usure, commercialisés comme disques renforcés. En résumé, ce sont des disques avec des fissures usinées sur la surface d'usure.
Justification ou besoin	Grâce aux dispositifs de sécurité intégrés au rotor, pourquoi exiger une commande hors service et un remorquage jusqu'à l'atelier pour une simple fissure n'atteignant pas le cœur du rotor, alors qu'une réparation en 30 jours suffirait ? Si le rotor et les garnitures de frein sont conformes aux spécifications minimales, la capacité de freinage n'est que très peu affectée.
Demande d’action	J'aimerais consulter un rapport technique sur les dispositifs de sécurité des rotors et les raisons pour lesquelles une fissure à 75 % est considérée comme hors spécifications (OOS). Il faudrait supprimer la condition OOS pour un rotor fissuré, sauf si la fissure s'étend dans la cuvette ou le moyeu du rotor, ou si la fissure est présente sur les deux surfaces d'usure du rotor.
Mesures prises par le comité	The OOS violation for a rotor cracked across more than 75% of the friction surface and thru the rotor to the vents or completely thru the rotor on a solid rotor was added to the OOSC in 2007 based on TMC’s Recommended Practice 652. The minutes for Issue Request 05-11 details the discussions at meetings prior to the inclusion into the OOSC in Atlanta in 2007. The inclusion, in this case, is not based on reduction of braking efficiency, but rather due to the hazard of a rotor coming apart or potentially brake pads or other components coming apart due to the potential chunking away of the pads due to the crack, creating a hazard to that vehicle and to other motorists on the road. Guidance on inclusion of items in the OOS Criteria, especially brake components, is taken from the manufacturers of these components and when they feel the defect should be considered an Imminent Hazard. Any crack, other than heat cracks, would be a defect and would require repair prior to re-dispatch. Any violation of regulation when it does not meet the OOSC, whether it is NSC Standard or FMCSR’s, is required to be repaired prior to re-dispatch so a 30 day repair order is never issued for any defect. The rotors mentioned as being manufactured with slots are also different because a rounded slot is different than a crack. A rotor with a crack will continue to have that crack get larger where a slot will not. The committee recalled that a radial crack 75% of the rotor radii was the OOS limit. TMC on when the Recommended Practice for disc brakes would be available, and reported that the existing TMC RP 608 Brake Drums and Rotors does cover rotor cracks. A separate, new TMC RP is in the works and is expected to be ready for balloting within a year, which covers Air Disc Brake Maintenance. Information (TMC’s Recommended Practice 652(T)) was provided to the committee. TMC’s Recommended Practice discusses light heat checking, heavy cracking greater than 75% of the braking surface width and deep grooves. Light heat checks, cracks less than .06 inches (1.5mm) deep or wide running in a radial direction, and grooves (circumferential) less than .06 inches (1.5mm) wide were considered not a violation. Cracks in vanes, cracks through solid rotors, and cracks into the vane area are cause for placing the vehicle in an out of service condition. The Vehicle Committee discussed what criteria inspector should use to distinguish between heat check cracks and heavy cracking. Usually the heavy cracking will, but not necessarily always, extend to one of the outer edges but could. Discussion centered on TMC’s RP 652 and when cracks in disk rotors would be considered an imminent hazard and should be placed out of service. A motion was made, seconded and passed to amend Section 1.f. by revising paragraph (1), adding a new paragraph (2) and (3). The amended section f. will read as follows: f. Brake Drums or Rotors (Discs) (1) Any portion of the drum has an external crack or cracks that open upon brake application or any portion of the drum is missing or in danger of falling away. (393.47(a)) (2) Any rotor (disc) with a crack in length of more than 75% of the friction surface and passes completely through the rotor to the center vent from either side or completely through a solid rotor. (393.47(a)) (2) Any portion of the rotor (disc) is missing or in danger of falling away. (393.47(a)) NOTE: Do not confuse short hairline heat check cracks with flexural cracks. (393.47(a))

Date d’inscription

9 juin 2017

Numéro de l’enjeu

17-030-VEH

Nom

john behrens

Organisme

hope towing

Adresse

1060-5th avehope, bc, v0x1l0United StatesVoir sur la carte

Téléphone

6047500238

Télécopieur

(604) 869-0049

Courriel

[email protected]

Comité

Comité des véhicules

État

Fermé

Résumé de l’enjeu

J'aimerais consulter un rapport de sécurité concernant les disques de frein fissurés et leur non-conformité lors des contrôle routier. Ce rapport préciserait les critères de réduction de l'efficacité des disques, notamment si la réduction de 20 % de la capacité de freinage s'applique. Si tel est le cas, sur un disque ventilé, chaque surface serait prise en compte dans le calcul. Il est possible de commander des disques avec des trous et des rainures usinés sur la surface d'usure, commercialisés comme disques renforcés. En résumé, ce sont des disques avec des fissures usinées sur la surface d'usure.

Justification ou besoin

Grâce aux dispositifs de sécurité intégrés au rotor, pourquoi exiger une commande hors service et un remorquage jusqu'à l'atelier pour une simple fissure n'atteignant pas le cœur du rotor, alors qu'une réparation en 30 jours suffirait ? Si le rotor et les garnitures de frein sont conformes aux spécifications minimales, la capacité de freinage n'est que très peu affectée.

Demande d’action

J'aimerais consulter un rapport technique sur les dispositifs de sécurité des rotors et les raisons pour lesquelles une fissure à 75 % est considérée comme hors spécifications (OOS). Il faudrait supprimer la condition OOS pour un rotor fissuré, sauf si la fissure s'étend dans la cuvette ou le moyeu du rotor, ou si la fissure est présente sur les deux surfaces d'usure du rotor.

Mesures prises par le comité

The OOS violation for a rotor cracked across more than 75% of the friction surface and thru the rotor to the vents or completely thru the rotor on a solid rotor was added to the OOSC in 2007 based on TMC’s Recommended Practice 652. The minutes for Issue Request 05-11 details the discussions at meetings prior to the inclusion into the OOSC in Atlanta in 2007. The inclusion, in this case, is not based on reduction of braking efficiency, but rather due to the hazard of a rotor coming apart or potentially brake pads or other components coming apart due to the potential chunking away of the pads due to the crack, creating a hazard to that vehicle and to other motorists on the road. Guidance on inclusion of items in the OOS Criteria, especially brake components, is taken from the manufacturers of these components and when they feel the defect should be considered an Imminent Hazard. Any crack, other than heat cracks, would be a defect and would require repair prior to re-dispatch. Any violation of regulation when it does not meet the OOSC, whether it is NSC Standard or FMCSR’s, is required to be repaired prior to re-dispatch so a 30 day repair order is never issued for any defect. The rotors mentioned as being manufactured with slots are also different because a rounded slot is different than a crack. A rotor with a crack will continue to have that crack get larger where a slot will not.

The committee recalled that a radial crack 75% of the rotor radii was the OOS limit. TMC on when the Recommended Practice for disc brakes would be available, and reported that the existing TMC RP 608 Brake Drums and Rotors does cover rotor cracks. A separate, new TMC RP is in the works and is expected to be ready for balloting within a year, which covers Air Disc Brake Maintenance. Information (TMC’s Recommended Practice 652(T)) was provided to the committee. TMC’s Recommended Practice discusses light heat checking, heavy cracking greater than 75% of the braking surface width and deep grooves. Light heat checks, cracks less than .06 inches (1.5mm) deep or wide running in a radial direction, and grooves (circumferential) less than .06 inches (1.5mm) wide were considered not a violation. Cracks in vanes, cracks through solid rotors, and cracks into the vane area are cause for placing the vehicle in an out of service condition. The Vehicle Committee discussed what criteria inspector should use to distinguish between heat check cracks and heavy cracking. Usually the heavy cracking will, but not necessarily always, extend to one of the outer edges but could.

Discussion centered on TMC’s RP 652 and when cracks in disk rotors would be considered an imminent hazard and should be placed out of service. A motion was made, seconded and passed to amend Section 1.f. by revising paragraph (1), adding a new paragraph (2) and (3). The amended section f. will read as follows:

f. Brake Drums or Rotors (Discs) (1) Any portion of the drum has an external crack or cracks that open upon brake application or any portion of the drum is missing or in danger of falling away. (393.47(a)) (2) Any rotor (disc) with a crack in length of more than 75% of the friction surface and passes completely through the rotor to the center vent from either side or completely through a solid rotor. (393.47(a)) (2) Any portion of the rotor (disc) is missing or in danger of falling away. (393.47(a)) NOTE: Do not confuse short hairline heat check cracks with flexural cracks. (393.47(a))

OOSC, Partie II, Article 1. g. (2) - Rotors fissurés