Re: BRAKES: Easamatic Power Brakes aka Bendix Treadle-Vac

Posted by Owen_Dyneto On 2009/5/14 13:04:03

Change or Not - The case for maintaining originality. Some buyers/owners of collectible cars want a Packard body on a new Chevy Yukon frame with all the modern amenities; others want to experience what it was like to drive and maintain an older car as they were built. Some potential purchasers see modifications as detracting from value, others see it as adding value - each owner needs to determine for himself where in this mix he wants to be. The Bendix TreadleVac was the OEM power brake unit for many car manufacturers including Chevrolet, Cadillac, Buick, Pontiac, Oldsmobile, Lincoln, Mercury, Edsel, Hudson, Nash, and Mercedes-Benz (gullwings no less). It was introduced about 1952 and I believe Lincoln was the last to use it in 1961. The unit was installed on tens of millions of cars over nearly a decade, without recall or redesign. Mounting particulars varied but internally they were all essentially identical.

Packard's service letters do not indicate a history of problems or failures with the unit. The technical threads of other car clubs and associations that used the TreadleVac are relatively devoid of comment of problems. A few Packard owners have reported catastrophic failure, though we have not benefited from knowing the quality of the core, the repair/rebuild history or the results of an autopsy to indicate the mode of failure. According to whom I believe to be the best of the TreadleVac rebuilders, problems are no more common than with any other type of single master cylinder system.

I believe the facts point to the TreadleVac as being a completely reliable power brake booster, though of course lacking the extra security of the later "dual cylinder" systems. However, I would NOT recommend that owners wishing to retain the TreadleVac rebuild their own units several reasons. First, it's just too important a part to not entrust to a professional who specializes in them. Secondly, there are "rebuild kits" available, some dating back to the 50s which should never be used, some new and fresh such as the Kanter kits, but the rebuilder cited above states that he has about 25 other individual parts made for his own captive use in each rebuild, these parts not being available to the do-it-yourselfer.