OOSC, Part II, Item 1. Brake System b. Front Steering Axle Brakes (2) (b) - Mismatched slack adjuster length

The Out-of-Service Criteria currently mandates that a commercial motor vehicle is to be place out-of-service for mismatched front steering axle brake adjuster length (See North American Standard Out-of-Service Criteria and Pictorial, Part II, Section 1b, page 23.) The purpose and intent of this mandate is that of the concern of pull to the left or right upon harsh braking due to unequal braking action at the steering axle. While unequivocally a violation of 49CFR393.47(c), the operation of a commercial motor vehicle with unequal front axle slack adjuster lengths of 1/2 inch is virtually undetectable due to the reduced brake force design of the front braking components combined with the wheelbase of the vehicle. Indeed, brake force calculations support this fact. With respect to an Out-of-Service violation, the proposal is to include this violation as OOS in those cases where the unequal deviation of the front axle slack adjusters is one (1) inch or greater. This would be consistent with other OOS realms mandating specific measurement thresholds, such as tires, brake stroke lengths, and brake shoe wear.

The above-referenced proposal is submitted for review and consideration for future amendment with respect to the Out-of-Service Criteria. Albeit not urgent, future consistency within the intent of the OOS Criteria is sought.

The above-referenced proposal is submitted for review and consideration for future amendment with respect to the Out-of-Service Criteria. Albeit not urgent, future consistency within the intent of the OOS Criteria is sought. Accordingly, the referenced section of the North American Standard Out-of-Service Criteria should be reworded to state (b) Mismatched brake adjuster length (1 inch or greater). (393.47(c))