23-028-VEH: OOSC, Partie II, Article 1. systèmes de freinage, a. (5) Freins à tambour pneumatique, (a) Bague manquante

Date d’inscription	12 juillet 2023
Numéro de l’enjeu	23-028-VEH
Nom	Eric Sundby
Organisme	MN State Patrol
Adresse	1110 Centre Pointe Curve, Suite 410Mendota Heights, Minnesota, 55120United StatesVoir sur la carte (s’ouvre dans un nouvel onglet)
Téléphone	12183960866
Courriel	[email protected]
Comité	Comité des véhicules
État	Fermé
Résumé de l’enjeu	Bagues de came en S manquantes
Justification ou besoin	Sur l'une des photos jointes, l'arbre à cames en S frotte contre le tambour, ce qui affecte le fonctionnement du frein. Il était correctement réglé, mais le frottement de l'arbre à cames en S bloquait la course du frein.
Demande d’action	Pour inclure dans la règle des 20 % l'absence totale de toute bague d'arbre à cames en S, ainsi que d'autres composants manquants ou cassés.
Mesures prises par le comité	The request is to add 20% brake defect criteria for the S-cam bushing missing. This situation likely resulted in another underlying issue aside from the missing bushing. A question was raised as to whether braking performance would be affected due to a brake application and the centering of the camshaft when the pads touch the drum. The committee discussed that a missing bushing would be like other brake components identified in the out-of-service criteria and should be included as a brake defect and in the 20% brake calculation. There were pictures of three different brakes shown, and in some cases, there were no other brake defects present. Whether or not brake performance is affected would not determine if a brake assembly has a defect and should be repaired. Inclusion as a 20% defect does not automatically place the vehicle out-of-service. An amendment to the 20% OOS condition to add a condition for the S-cam bushing missing in Part II, Item #1.(5)(a) was made. Discussion about brake effectiveness and how a missing bushing would affect performance. 1. Brake Systems a. Defective Brakes (5) Drum (Cam-Type and Wedge) Air Brakes Missing or broken brake shoe, lining, return spring (shoe or chamber), anchor pin, spider, cam roller, camshaft, camshaft bushing (missing only), pushrod, yoke, clevis pin, clevis pin retainer (e.g., cotter pin), brake adjuster, parking brake power spring or air chamber mounting bolt. The “2006-01, Camshaft bushing” inspection bulletin would also need amended due to the edit to the OOSC. Discussion to amend the wording of the document to only apply to worn bushings and align with the OOSC criteria change. A change was also made to rename the bulletin from “Camshaft Bushings” to “Worn Camshaft Bushings” with edits to refer to worn bushings only.(This bulletin amendment would be dated for April 1, 2024 to correspond with the change in the OOSC)
Documents à l’appui	Missing-S-Cam-Bushing-3.JPG (s’ouvre dans un nouvel onglet) Missing-S-Cam-Bushing.jpg (s’ouvre dans un nouvel onglet) Missing-S-Cam-Bushing-2.JPG (s’ouvre dans un nouvel onglet) IMG_2596.JPG (s’ouvre dans un nouvel onglet)

Date d’inscription

12 juillet 2023

Numéro de l’enjeu

23-028-VEH

Nom

Eric Sundby

Organisme

MN State Patrol

Adresse

1110 Centre Pointe Curve, Suite 410Mendota Heights, Minnesota, 55120United StatesVoir sur la carte

Téléphone

12183960866

Courriel

[email protected]

Comité

Comité des véhicules

État

Fermé

Résumé de l’enjeu

Bagues de came en S manquantes

Justification ou besoin

Sur l'une des photos jointes, l'arbre à cames en S frotte contre le tambour, ce qui affecte le fonctionnement du frein. Il était correctement réglé, mais le frottement de l'arbre à cames en S bloquait la course du frein.

Demande d’action

Pour inclure dans la règle des 20 % l'absence totale de toute bague d'arbre à cames en S, ainsi que d'autres composants manquants ou cassés.

Mesures prises par le comité

The request is to add 20% brake defect criteria for the S-cam bushing missing. This situation likely resulted in another underlying issue aside from the missing bushing. A question was raised as to whether braking performance would be affected due to a brake application and the centering of the camshaft when the pads touch the drum. The committee discussed that a missing bushing would be like other brake components identified in the out-of-service criteria and should be included as a brake defect and in the 20% brake calculation. There were pictures of three different brakes shown, and in some cases, there were no other brake defects present. Whether or not brake performance is affected would not determine if a brake assembly has a defect and should be repaired. Inclusion as a 20% defect does not automatically place the vehicle out-of-service.

An amendment to the 20% OOS condition to add a condition for the S-cam bushing missing in Part II, Item #1.(5)(a) was made. Discussion about brake effectiveness and how a missing bushing would affect performance.

1. Brake Systems a. Defective Brakes (5) Drum (Cam-Type and Wedge) Air Brakes Missing or broken brake shoe, lining, return spring (shoe or chamber), anchor pin, spider, cam roller, camshaft, camshaft bushing (missing only), pushrod, yoke, clevis pin, clevis pin retainer (e.g., cotter pin), brake adjuster, parking brake power spring or air chamber mounting bolt.

The “2006-01, Camshaft bushing” inspection bulletin would also need amended due to the edit to the OOSC. Discussion to amend the wording of the document to only apply to worn bushings and align with the OOSC criteria change. A change was also made to rename the bulletin from “Camshaft Bushings” to “Worn Camshaft Bushings” with edits to refer to worn bushings only.(This bulletin amendment would be dated for April 1, 2024 to correspond with the change in the OOSC)

Documents à l’appui