Packard Forum Index » Post-War (1946-54)

That is a good question. I would also be interested in hearing what others think but I don't think it is an issue.

Packard made the remote kits available for 55-6 so they must have sanctioned them for both types of brakes. I didn't see a mention of the kits for earlier cars so not sure when they first became available. Packard did make a change to a different model BTV in 55. What all the differences might be, I don't know but apparently the older cover is one issue or might have been one of the changes. I had a 56 with a flat lid and blocked port as have several other people. Others have the lid with a bubble in the stamping over the relief port to provide an air channel. How or when the two covers might be used seems to be the question. The way the unit sits, I would think there is probably a minimal amount of air trapped above the fluid -- even with the remote fill.

IMO, the far worse problem is to have the relief port hard blocked. If the hydraulic seal leaks, there is absolutely no place for the fluid to go other than be forced into the vacuum side under pressure. That seal leaking seems to be the more problem side. At least with the port open --even though filled with fluid -- there is some relief and an easier place for fluid to go rather than being forced backward thru the vacuum seal.

If the vacuum side seal leaks (which seems to be less common) the vacuum is not present all the time. While fluid getting sucked in could happen as brakes are applied and held, it should be less of a problem and by virtue of the kit, visible to an observant driver who might question --no matter the reason -- why the reservoir level is dropping rapidly. Better than having the surprise of no fluid in the master that happens without warning on the non remote cars.

I recently rebuilt my Bendix Treadle-Vac, using the kit from Kanter's.

As a side note - gosh there are so many small parts in there, and you have to be very careful to get everything in and in the right orientation/order. It is very much more complicated than any more modern master cylinder/brake booster system.

My unit, which was on a 1953 Packard Cavalier, had the cover as in an an earlier post:

The gasket did not block the port, but on the other hand the cover really didn't seem to provide a lot of room for the port either.

But no matter - I did a very close inspection and it appeared that the port itself did not go through. In other words, it was blocked off by manufacture. It did not lead anywhere. The casting was not drilled through to the seal area.

From reading these posts it sounds like Bendix went through many iterations of this "relief port", to the point that late in production they didn't include it at all. Perhaps my BTV was replaced at some point in time during maintenance, and the new unit had the port blocked off intentionally.

Attach file:

---

  (21.42 KB)