Re: Treadlrvac???????

Posted by Craig Hendrickson On 2009/5/4 16:23:23

I was motivated to change out the Bendix Treadle-Vac (BTV) after 3 failures on 3 different units. One failure was complete (no brakes) at 20mph and the other two were leakers stopped in traffic. After conversing with six other Packard owners about failures with their BTV, that was enough for me.

The Master Power Brake dual master 7" unit documented on my 1956PackardPanther.com website has been superseded by another number, but I am told it is essentially the same. It does fit in the same location as the BTV with very little modification. The remote fill is optional, but well worth it.

HOWEVER, the MPB unit requires a 3:1 pedal ratio to generate enough line pressure to actuate the brakes. The BTV pedal has 1:1 (direct) and this does NOT work. I came up with a way to remount a 1956 pedal assembly to create the requisite 3:1 ratio. It is not pretty and it relocates the pedal itself lower toward the floor, but it has proven to be completely reliable over these many years. It is just a matter of retraining your muscle memory to the new pedal position.

Craig