Commercial Vehicle Safety Alliance

Fecha de registro	9 de junio de 2017
Número de asunto	17-030-VEH
Nombre	john behrens
Agencia	hope towing
Dirección	1060-5th avehope, bc, v0x1l0United StatesVer en el mapa (se abre en una pestaña nueva)
Teléfono	6047500238
Fax	(604) 869-0049
Correo electrónico	[email protected]
Comité	Comité de Vehículos
Estado	Cerrado
Resumen del asunto	Me gustaría ver un informe de seguridad sobre rotores agrietados con respecto a OOS en la inspección en carretera, los criterios para la disminución de la efectividad del rotor, si se aplica la reducción del 20% en la capacidad de frenado, de ser así, entonces en un rotor ventilado, cada superficie contaría en la fórmula, se pueden pedir rotores con agujeros y ranuras cortadas en la superficie de desgaste que se comercializan como un rotor de mayor resistencia. En esencia, un rotor con grietas mecanizadas en la superficie de desgaste.
Justificación o necesidad	Con las características de seguridad integradas del rotor, ¿por qué sería necesario un pedido de repuesto fuera de stock y el remolque del vehículo al taller por una simple grieta que no se extiende al interior del rotor, cuando bastaría con una solicitud de reparación en un plazo de 30 días? Si el rotor y el material de fricción de los frenos se encuentran dentro de los límites mínimos, la capacidad de frenado no se ve afectada significativamente.
Solicitud de acción	Me gustaría ver un informe de ingeniería sobre las características de seguridad de los rotores y las razones por las que una grieta del 75% se considera fuera de especificación (OOS), y eliminar la condición OOS para un rotor agrietado a menos que la grieta se extienda hacia la cavidad o el cubo del rotor, o que la grieta esté en ambas superficies de desgaste del rotor.
Medidas adoptadas por el 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))

Fecha de registro

9 de junio de 2017

Número de asunto

17-030-VEH

Nombre

john behrens

Agencia

hope towing

Dirección

1060-5th avehope, bc, v0x1l0United StatesVer en el mapa

Teléfono

6047500238

Fax

(604) 869-0049

Correo electrónico

[email protected]

Comité

Comité de Vehículos

Estado

Cerrado

Resumen del asunto

Me gustaría ver un informe de seguridad sobre rotores agrietados con respecto a OOS en la inspección en carretera, los criterios para la disminución de la efectividad del rotor, si se aplica la reducción del 20% en la capacidad de frenado, de ser así, entonces en un rotor ventilado, cada superficie contaría en la fórmula, se pueden pedir rotores con agujeros y ranuras cortadas en la superficie de desgaste que se comercializan como un rotor de mayor resistencia. En esencia, un rotor con grietas mecanizadas en la superficie de desgaste.

Justificación o necesidad

Con las características de seguridad integradas del rotor, ¿por qué sería necesario un pedido de repuesto fuera de stock y el remolque del vehículo al taller por una simple grieta que no se extiende al interior del rotor, cuando bastaría con una solicitud de reparación en un plazo de 30 días? Si el rotor y el material de fricción de los frenos se encuentran dentro de los límites mínimos, la capacidad de frenado no se ve afectada significativamente.

Solicitud de acción

Me gustaría ver un informe de ingeniería sobre las características de seguridad de los rotores y las razones por las que una grieta del 75% se considera fuera de especificación (OOS), y eliminar la condición OOS para un rotor agrietado a menos que la grieta se extienda hacia la cavidad o el cubo del rotor, o que la grieta esté en ambas superficies de desgaste del rotor.

Medidas adoptadas por el 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, Parte II, Artículo 1. g. (2) - Rotores agrietados