OOSC, Part II, Item 1. Brake Systems a. (7) (f) - Contaminated linings and Drums (Hydraulic Brakes)

Last week I inspected a 5 ton truck with hydraulic brakes and spring parking/emergency brakes. The front brakes on the unit were rotors/calipers and the rear brakes were drum brakes. The drum brakes had a backing plate with a number of inspection holes in the backing plate. When my partner and I went underneath the vehicle, we noticed a fluid leak coming from Axle 2 left side. Upon further inspection and driver interview, we were able to determine the vehicle was leaking brake fluid from the brake. The driver was able to confirm he had to fill the brake master cylinder every couple of days. We were unable to see through the backing plate to determine where the leak was coming from. We had the driver fully apply the service brakes and hold the service brakes in the applied position. No fluid came out the inspection hole during this time. When the driver applied the parking brake, a small amount of fluid came out of the drum. During the course of the inspection, a puddle of fluid accumulated on the ground and the inside tire was wet with fluid. It was obvious there was a leak, but the leak was not big enough to have fluid come out of the inspection hole while the service brakes were applied. As previously mentioned, the brakes had a backing plate, therefore we were unable to determine the exact location where the brake fluid was leaking. It seemed as though the fluid needed time to work its way out of the drum. When examining the CVSA Out of Service Criteria, it appears as though this issue does not fit within the manual.

Under section 1 (a)(5)(vi), Drum(Cam-Type and Wedge) Air Brakes, the wording states; \"the friction surface of the brake drum and the brake friction material are contaminated by oil or grease.\" This section is specific to air brakes. If an air drum brake was discovered in this condition, it would be considered defective under the CVSA criteria. Under section 1(a)(7)(f), Hydraulic and Electric Brakes, the wording states; \" Friction surface of the brake rotor and the brake friction material are contaminated by oil, grease, or brake fluid.\" This section is specific to a rotor and does not include a drum brake. Under section 1(b)(4)(f), Hydraulic Brakes (front steering brakes)the wording states; \"The friction surface of the brake drum or rotor and the brake friction material are contaminated by oil, grease, or brake fluid.\" This section fits what I saw on the roadside. However, this section is specific to a front steering axle brake and does not include a rear brake. I could not find an out of service condition listed for what we were dealing with on the roadside.

Vehicles with air drum brakes are considered to have a defective brake if, \"the friction surface of the brake drum and the brake friction material are contaminated by oil or grease.\" Air disc brakes are considered to have a defective brake if, \"the friction of surface of the brake rotor and the brake friction material are contaminated by oil or grease.\" Hydraulic and electric front brakes are considered to have a defective brake when \"the friction surface of the brake drum or rotor and the brake friction material are contaminated by oil, grease, or brake fluid.\" Since all these brakes are considered to be defective, it seems strange that a rear hydraulic drum brake would not be considered defective with an oil soaked drum. I would propose that a vehicle found in this condition should be considered to have a defective brake. I believe this vehicle should have been placed out of service due to 1 of 4 (25%) defective service brakes. I propose the wording of section 1(a)(7)(f), Hydraulic and Electric Brakes be amended to be the same as section 1(b)(4)(f), Hydraulic Brakes (front steering brakes). The wording I am proposing would be, \"The friction surface of the brake drum or rotor and the brake friction material are contaminated.\"