Re: BigKev's 1954 Packard Clipper Deluxe Sedan

Posted by Owen_Dyneto On 2008/12/18 14:38:24

I too wonder about the gaskets. They don't exist on any application I can remember. I see the gaskets in the exploded parts drawing you provided but in my opinion they are not really necessary. The seal on the inside of the break drum does the sealing

The gaskets exist in all drum brake applications I've worked on, to the best of my memory. I guess you could argue that they're not absolutely essentially, but they are certainly important. Grease, subjected long enough to temperatures and pressures, will have some fraction liquify to a heavy oil. The seal in the drum is a grease seal, not an oil seal, so any liquified grease that escapes is captured by the lip on the retaining plate and directed away from the shoes by a small hole on the backing plate; thus it harmlessly runs out on the inboard (non-shoe) side of the backing plate. Without the gasket the liquified grease could escape on the shoe-side of the backing plate and make contact with the shoes, as Kevin has pointed out.