Tonight, join the crew of Allen and Donna Smith as they host former driver Allan Powell, who contends that the problem of treadle valve corrosion is going under-reported in too many accident investigations around the country, where brakes being out of adjustment is often the only cited brake-related factor.
A valve corroded inside the housing — Powell cites increased use of liquid de-icing chemicals as a potential primary culprit — is a killer for the air-brake system, given the valve is “the brain of the air brakes” of a fashion, Powell writes. “It is the first valve that supplies the correct amount of air pressure to the rest of the valves and brake chambers on the secondary side of the brake system.”
He goes on:
Pressing down the treadle valve pressurizes the air brake canisters, pushing a rod to the brake adjusters with the correct degree of pressure as the brake pads press on the drum. The brakes will not work if the treadle valve sticks or does not perform correctly.
Not that you needed the primer, necessarily, though Powell suggests too many investigators’ preoccupation with brake adjustment post-crash may be masking a problem more drivers should pay greater attention to. Read more of his analysis here.
Add relatively new liquid de-icers on the roads over several years (de-icers saw a “closer look” in our January issue, toggle to p. 28) to that mix and, Powell says, you’ve got a recipe for a growing problem. What do you think? Have you had to replace a valve due to corrosion recently?
Join his conversation on the Truth About Trucking online radio show this evening — Thursday, Jan. 24, 6 p.m. Central. Utilize that link as well to hear the rebroadcast on-demand following the live show. Call-in number to listen/participate on your phone: 347-836-9170.
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