Packard Forum Index » V-8 (1955-56)

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No, and I don't have access to a Buick of that vintage to examine it. I'm more curious as to Cadillac's mounting preference:

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I'm thinking that "bubble" in the illustration represents a reinforcing rib about the perimeter of the cover that I've seen on earlier units. It's not present on any of the covers on my V8s. Perhaps this was another minor revision, noted only on the supplier's engineering drawing.

Only an inspection of an actual unit will tell fer sure.

Maybe I'm just lucky, then, that my rebuilds used earlier editions of the kit that had the same style port valve.

With a more corrosion resistant spring, a port valve stem that met the suppliers original specifications, and all other things being equal, I'd expect to have as many miles/years of service out of the unit as what my dad got in the Exec - even more.

As you can see, a 1956 Cadillac has it mounted vertical and up near the radiator. A lot better arrangement than putting the damn thing under the steering column, that's for sure. At least it gets it away from the heat, which I'm thinking is a good point towards failure.

Also, take a look at this website:http://caddydaddy577.corecommerce.com/1956-1957-1958-Cadillac-Bendix-Treadle-Vac-Master-Cylinder-Rebuild-Kit-FREE-shipping-in-the-USA-p3054.html

And the picture they show for their rebuild kit:




Makes me wonder if people are selling a generic BTV rebuild kit.

And on another note, I'm thinking that the incorrect gasket sealing off that port is the reason why people are finding fluid in the vacuum side of the unit, it has no where to go and the pressure of the return stroke is pushing it past the rear seal and into the booster side of the unit.

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That's what I'm thinking, too. I think that the kits available today are incorrect for '55-'56 Packards, and you may be better off comparing each and every piece if you're insistent on using something that will eventually cause damage and possibly kill someone.

That Cadillac lid would appear to allow for the port. It's either under the squared portion or that little pipe looking like thing between the square and fill opening.

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I noticed that too, it looked like a little loop for a spring to attach to, but maybe you're right and it's a tube to allow fluid back through. If it is, then it explains the gasket that seals off the port.

Looks like we should be letting the suppliers know that they need to be selling the '54 and back style gaskets in the '55-'56 Packard kits.

Here's a 1956 Buick BTV parts view, ignore the red markings. Notice the side mounted reservoir and the absence of a compensator port. This looks like a direct fit replacement for the Packard version. Too bad it's one year only and rare as hen's teeth:


The outside view, I like how they made the reservoir a little more accessible compared to Packard's version:

Interesting and quite a bit different. Wonder if this is Bendix or a GM copy version. Item 32 & 33 almost looks like there is a cup arrangement, but maybe just a second seal & retainer. If a cup, wonder where the fluid path from the closed end back to outlet would be. At any rate, don't see anything like a compensator valve.

EDIT: Looking at Chilton, it appears to be a cross between the HRT by Bendix and the Moraine version. Not quite either one but more in common with those than the BTV we all know and love. 57-9 Buicks used those units plus one other. Chiltons doesn't mention them using the same as Packard--just those cars on that other list.

I have 2 spare complete treadle Vac Brake Units out of '55 Packard 400's. I will donate ONE of these units to anyone on this list who will:

1.Dissect it. Even if they have to cut it in half and have a working model to re-enact failure.

2.Share this information only on PackardInfo.com (With Pics) with thorough explanations and a possible solution.

PM me with your address and I'll have it on the road and delivered to you within 5 business day. (Continental US Only)

Lets solve this problem before somebody gets killed.