Re: Treadlrvac???????

Posted by PackardV8 On 2009/5/4 21:49:27

The TreadleVac in it's day was just fine because OEM kits were available. Who knows what materials are used in modern day kits????? This especialy true of the COmpensator Valve which makes the TV unit a peculiar design.

There is also issues with the fluid getting sucked into the vacuum unit.


ASIDE from the above issues with the Bendix TreadlVac there is a common misconception that a 'modern' DUAL or Tandem master cylinder is safer. Perhaps true but only to a marginal or negligable degree is the tandem safer.

THERE IS a DANGEROUS down side to the tandem master cylinder espeicaly at very low speeds. This danger element is really only evident at very low speeds of say 5 mph or less. It can be experienced on very slippery roads dur to ice, heavy snow, moss covered creek beds, descending steep hills, loose gravel and other such low speed negotiations of peril.

The problem is that the rear wheel cylinders do not recieve equal pressure as the front wheel cylinders and what happens is that the rear wheels will tend to continue driving the car forward while the front wheels loose traction due to slippery surface.

To eleminate the above problem, with a stick one can disengage the clutch. An automatic requires a fast shift to nuetral. The problem is that pushing in the clutch is somewhat natural reflex at very low braking speeds. Shifting to nuetral IS NOT a natural reaction.

I do not like the tradlevac due to various reports from reasonably technically astute people as well as my own experiences with the BTV. But, this has NOTHING to do with the fact that the BTV is single cylinder.

NONETHELESS, i do not like the modern dual master cylinders either. For 56 and 55's (don't know about earlier Packards) the best bet is to use the 96'ish Ford explorer power unit and brake pedal assembly with a ranger master cylinder. Mount it thru the left fresh air vent hole in the fire wall. U will need 2WO of the F pedal assemblies and stop lite switch to make one. Cost it out at about $150. Pedal position will be about 1 inch higher than stock packard pedal.

More research needs to be done to see if an earlier SINGLE F master cylinder will fit the 96'ish Explorer power unit,