AIR DISC BRAKES

Formed during the CVSA sponsored Brake Safety Symposium Dec 5-7, 2006 to: Develop a simple but effective air disc brake Develop a simple but effective air disc brake inspection procedure for CVSA use (Compatible for all air disc brake products) (Compatible for all air disc brake products) Provide training and technical support in the implementation of the procedure Provide training and technical support in the implementation of the procedure Comprised of brake manufacturers and enforcement officials Comprised of brake manufacturers and enforcement officials ADB TASK FORCE

CHARACTERISTICS Chamber/ DDSB direct mounted to the back of the caliper Caliper Assembly permanently lubricated and sealed Actuation / Adjuster mechanisms totally enclosed in caliper assembly

ADB Task Force - History ATLANTA Presented a draft inspection list of maintenance components relative to Air Disc Brakes Presented a draft inspection list of maintenance components relative to Air Disc Brakes Evidence of brakes working. (IE:- clamping rotor) Rotor friction surface (area of rotor where pads are in contact) is not corroded. With brake released (off) – (caliper slides, play) / brake on With brake applied (on) – (caliper is tight – no movement) Cracked rotors (shields possible hindrance to view rotors) Heavy oil contamination of rotor / pads Loose pieces, loose bolts. Rock / slide caliper a little (confirm the brake is not seized) Mirror inspections for presence of 2 pads. Presence of pad springs and pad strap retention device. Adjuster covers and other plugs installed. Chamber Size Comparison across the axle.

ADB Task Force - History ATLANTA Air Disc Brake Task Force asked to narrow down the component list to those that would be easily inspected on roadside. Air Disc Brake Task Force asked to narrow down the component list to those that would be easily inspected on roadside.

ADB Task Force - History PITTSBURGH Components & Inspection Procedure visually check of valve stem on steering axle visually check of valve stem on steering axle check caliper slide pin movement check caliper slide pin movement verify presence of pad hold down parts verify presence of pad hold down parts check for rotor cracks through to cooling channel check for rotor cracks through to cooling channel check for bottom vent hole open at brake chamber check for bottom vent hole open at brake chamber check for caliper/chamber - no movement check for caliper/chamber - no movement new checks as deemed necessary. new checks as deemed necessary.

ADB Task Force - History PITTSBURGH Testing Tool measure rotor/pad (universal tool) measure rotor/pad (universal tool)

ADB MEETING- Columbus, OH ATTENDEES Ron Plantan - Bendix Jim Szudy - Bendix Scott Corbett - Haldex Norman Oha - Meritor Wabco Dick Radlinski – MGM Brakes Robert Nechvatal - Bendix Rolf VanderZwaag - Ontario Trucking Association Luke Loy – FMCSA Collin Mooney – CVSA Steve Shaffer – Battelle Kerri Wirachowsky – Ministry of Transportation, ON Joe Bowling – Virginia State Police Held January 18, 2008

ADB MEETING- Columbus, OH Components were compared to regulations Prototype tool was tested on vehicles that were provided Two different tractors and an axle for a trailer were looked at with different brake styles Discussion on components that are considered maintenance issues vs enforcement/imminent hazard for OOS criteria Draft of Procedure and OOS criteria developed

DETERMINED INSPECTION COMPONENTS Rotors Cracked Cracked Contaminated Contaminated Metal to Metal Contact (Pad Wear Down to Backing Plate) Metal to Metal Contact (Pad Wear Down to Backing Plate) Heavy Rust (Inoperative) Heavy Rust (Inoperative)

Metal to Metal Contact

Heavy Rotor Rust Surface Rust Acceptable for a Level V Inspection Indication of Inoperative Brake on a Level I Inspection

Other Components MISSING OR BROKEN CALIPER MISSING OR WORN PADS MISSING OR LOOSE CALIPER MOUNTING BOLTS LOOSE, MISSING OR MISMATCHED CHAMBERS ROTOR DEFECTS Pad Retaining Components

Pad Retaining Component

Chamber Mounting Bolts

Caliper Mounting Bolts

Exposed Pushrod ADB Older Style uncommon if inspected, measure chamber and pushrod stroke the same as S-Cam brake

Procedures and Components Determined not for Roadside Inspection Visual check of valve stem on steering axle Visual check of valve stem on steering axle It was explained that the valve stem (in certain circumstances) may rub on the caliper and eventually cause a leak. It was determined that this condition is already inspected during the front tire inspection and would result in an OOS condition on a tire if a leak was present. It was concluded that it is not considered a brake violation. It was explained that the valve stem (in certain circumstances) may rub on the caliper and eventually cause a leak. It was determined that this condition is already inspected during the front tire inspection and would result in an OOS condition on a tire if a leak was present. It was concluded that it is not considered a brake violation.

Procedures and Components Determined not for Roadside Inspection Check caliper slide pin movement Check for caliper/chamber - no movement When the movement was checked from vehicle to vehicle, there was a significant difference between each vehicle and the amount of movement. Some were extremely difficult to move and were barely noticeable. Due to the inconsistencies between vehicles, it was determined this test at roadside is not practical. The other consideration was that the best way to test for play is to grip the ports of the air chamber which caused concern that damage may occur during a roadside inspection. The test for no movement is not necessary if we are inspecting for heavily rusted rotors.

Procedures and Components Determined not for Roadside Inspection Check for bottom vent hole open at brake Chamber Due to the lack of regulatory support for this condition, it was determined that this is a maintenance issue and there would be no violation reference for the absence of the vent hole. Due to the lack of regulatory support for this condition, it was determined that this is a maintenance issue and there would be no violation reference for the absence of the vent hole.

Brake Tool measure the thickness of the rotor

Brake Tool Find the back of the brake pad

Brake Tool See if the tool touches the back of the caliper