Talk:Drum brake

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Automotive drum brakes: several manufacturers like Bendix and Lockheed made drum brake systems for trucks, busses and automobiles, each had there own peculiarities,some were difficult to service, some worked well others not so well. A good mechanic had to know how to set the cams as well as how to change the shoes. Usually there was/is a primary and a secondary brake shoe, one being shorter than the other,when set up properly the primary shoe engaged first and through a cam and lever system the inertial force generated from its contact with the rotating drum caused the secondary show to engage the drum with greater force.Hydraulic brakes were much safer and more reliable than the mechanical brake systems used on some cars before 1942, both types required that the brake shoes be adjusted correctly as the shoes wore down. Vaccuum systems assisted in boosting braking force and in mechanical brake systems allowed the rod and lever systems to be simpler.After WWII self adjusting brakes were in vogue. The system used a lever which transmitted motion of the brake shoes to the adjusting screw. The system worked but not always well,some mechanics did not lubricate them or install the levers and cables correctly when doing a brake job. The system was prone to gumming up due to oil, brake and road dust and moisture. The system often failed to work after a couple of winters where road salt was used. In general disc brakes are more effective and easier to service.

[edit] Cleanup

This article repeats itself a lot. The decription of the self-adjustment capability and the use of drums for parking brakes is mentioned in the article twice. 81.178.235.56 16:39, 19 January 2007 (UTC)