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

55PackardGuy wrote:
Jim,

I was not the one who posted on the "bubble lid." I don't remember who brought it up, offhand, but it interested me because I was not sure if I had that lid or not. If it refers to raised portions of the reservoir cover that can be seen from outside, I think I might have one. I thought that they might provide channels for fluid flow, especially clearance for the relief port, but when I looked on the inside of the lid, I couldn't make out any evidence that the "bubbles". It looked to me like they were just cast into the outside of the cover.

As for your vacuum leak, I'd sure check the hoses carefully, if you haven't already. The ends of all of mine are hard and cracking. I removed one end from the manifold adaptor and the end just fell apart. I cut it about half an inch shorter to get to some reasonably good rubber. I'm amazed I don't have leaks, given that even this "good" part of the hose was not exactly pliable. I'm tempted to get them all replaced.

You know, some of these failures we blame on the BTV come down to just plain old age and lack of maintenance, I think. It's remarkable to me that the system holds up as well as it does over such long periods of use and disuse. If it just didn't have the habit of going out completely and suddenly, I would give it more credit. I blame those catastrophic failures on engineering deficits. No brake booster should be able to vacuum the MC dry like that.

HH56 wrote:
Am willing to concede bubble lids are out there but thinking they more likely came on exchange or service units when Packard was no longer in the picture. It might have even been a Studebaker or SASCO supplied item. I can only say none of the units I've been up close and personal with have had them.

One good thing to check with no or intermittent reserve vacuum is the check valve at the manifold end. Those have been known to have issues. It probably hasn't been examined in 50 years so a good look see and cleaning might be in order. Other than that or a dried or cracked hose or pinhole in the reserve canister, not much is left.

PackardV8 wrote:
Pitting in the bore for the seal is not likely to cause a sudden and total loss of brakes. THAT ASSUMES that one is keeping check on the brake fluid level. The pitting could certainly cause A GRADUAL loss of fluid as it leaks past the seal at any point.

My 56 Exec never had any significant brake effect failure in 4 years and 10k miles . BUT, i had to top off the reservoir every 200 to 300 miles. So it was leaking but not bad enuf to indicate any problem while driving.

The debris that is shown in the reservoir in the above pic is not uncommon for ANY master cylinder. However, in the case of the BTV THE DEbris can interfere withthe closing and sealing of the compensatorvalve and thus cause a complete and total loss of brakeing effect. Complete and total loss as in ZERO braking performance. Note That the compensator valve is peculiar only to the btv which means that no other master cylinder design usrs anything that resembles such a compensator valve.