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

Well, back on topic here.

Got the car back from the shop. The brake lights started working as soon as vacuum hose was hooked up again (yes, I was right about that, thank you) and the vacuum hose was disconnected and could be reached from inside the car (yes, HH, you were right about that, thank you). The new accel pump improves driveability a lot. Around town, taking it out of OD also helps driveabiliity because you get engine braking.

I need all the braking I can get. It seems the new shoes are wearing in nicely. There's not much complaining coming from them any more, and the car CAN stop straight and smooth.

However, I have a case of EASA-FADE that has me perplexed. I don't expect modern-style stops, and it stops pretty good most of the time. But just following a slightly harder or longer stop, the same pedal pressure doesn't come close to being able to stop the car.

Do the brakes possibly need to be adjusted tighter due to things "stretching out" after a long time of no-power-assist braking? Or could it be something else? I don't believe it's normal fade.

BTW, the vacuum hose was still OK, and the mechanic put a zip tie on each end of it. I think that might've been a good solution... no metal to chafe against the hose. Kind of clever, although some may, of course, disagree. Remember though, don't be too harsh as I am STILL not an expert, and don't believe I want to be one.

Finally, the mechanic noted that there is some brake fluid drawn up into the rear part of the MC. It comes from around the main rod from the pedal where it enters the MC. Other than losing some fluid, I'm wondering if this is part of the fading problem-- as MC gets used harder, some pressure is lost as fluid seeps through. Warmer fluid seeps more, more pressure is lost until bigime fade... again not an expert on this.

Sounds like more $$ to me, though. Detecting when that's the case is my real expertise.

I would check some things fairly soon. It will require a disassembly of the BTV. The condition of the pot metal casting would be one. If it has developed pits up in the casting top around the seal area as is pretty common, the fluid can be seeping around the seal. The piston could have also developed a corrosion ring where it has sat against the seal lip and is leaking. Of course, the seal could also be hard or cracked.

There was a discussion last year on the reservoir gasket. Packards lid is the same original item as was used on the first BTVs which had the relief port opening slightly below the top of reservoir lip. The later BTVs had the relief port casting all the way to top. Gaskets were designed for those but for use with a lid either having the raised bubble over the relief port or the elevated tube. Other mfgs used one of those styles. Packards old flat lid and the high relief port in combination with the full gasket completely blocks the relief port. Any fluid that leaks past the seal has no where to go. Leaking fluid is forced into the vacuum side and if the vacuum side seal is leaking, there is no way to draw air from reservoir so it pulls fluid. Some original never touched units have been found with the problem so apparently it wasn't recognized as a problem before time ran out.

Solution is to either flip the gasket 180 so the port area of the gasket is at the front or cut the gasket over the port so there is an opening into the reservoir.

HH,

Do you think that might be a solution to the fade problem? I know this BTV beast will eventually have to be gone through completely, but I want to drive it before winter sets in, then lay it up for the heavy work on the off-season. I also wonder about just switching it over to manual brakes. Is this reversible? I would not want to abandon the originality of the car, but I think I'd enjoy driving it more in the meantime with plain ol' manual brakes that might give me some warning before they go pffft!

Thanks for your prompt reply to my last post. Without youse guys, I and my mechanic would not be very far beyond square one with this car yet, other than the the brake job and greasing it.

BTW, anyone in the Minneaplis/St. Paul area would do well to talk with this mechanic. He is very interested in old cars and a fast learner. He is also old school without being too old, if you know what I mean.

Anyone interested, please PM me.

Kind of depends on what you mean by fade. If it's the typical where the hotter the brakes get, the less the brakes then unless you are really on them or they are dragging, not sure what the cause would be.

You mentioned the fluid in master had gelled. Assume the cylinders were gone thru?? If not, that might be a starting point. Several have mentioned they feel the new linings sold today don't have the stopping power of the old. If the new shoes were installed without arcing, then that could also be contributing since the contact area would be somewhat diminished until they are worn in.

If the pedal seems to be getting harder the longer pressed, you might look at the check valve at the vacuum source on manifold or carb base. If that is dirty or rusted and not sealing, then vacuum supply could be leaking off and be insufficient after a few seconds.

As to changing to manual, that is quite the project and almost requires a parts car for visual aid and to have all the small pieces. It could be reversed but again, a project.

Quote: for the inclusion of your '54 Clipper Deluxe Touring Sedan in the Registry!

HH,

I'm not sure what "arcing" is, although I made sure the ends of the linings were scuffed. The linings are 100% Raybestos. Of course, there's no asbestos in them, which might have made the old linings a bit "stickier."

By fade I mean loss of stopping power on a second stop following a moderately long stop or slow-down.

The wheel cylinders are all new, and all the gell was cleaned out before they saw any use.

Your additional comments, plus the one about the gasket on the MC are all of great interest.

Ozstatman:

There is an interesting story in the notes on the Registry entry for this Packard. An almost unbelievable story, but true. It shows once again that these cars are not just cars, but History, and people's lives are intricately entwined with them.

NOTE:

The new Shop Manual's here! The new Shop Manual's here! And it is a beautiful reproduction.

Here's where I got it:

Faxon Auto Literature
3901 Carter Street, Riverside CA, 92501
www.faxonautolit.com
1-800-458-2734

This is my second excellent experience with these guys. There is no need to mess up an original Owner's Manual or Shop Manual. I would recommend you get one of these.

Very reasonable, especially considering the quality.

Arcing is grinding the shoes linings slightly to perfectly match the actual inner diameter of the drum so the entire shoe makes contact from the start. Without it, eventually the contour or any high spots on the shoes linings will wear down so the entire surface makes even contact but takes awhile.

It used to be a routine part of the job and every good brake shop, garage & larger parts store had the machines. The service has apparently fallen out of favor -- most likely due to regulations on dust. The theory now is the shoes come biased or pre-arced and you change the drum to match the shoe if the diameter doesn't match. Obviously the people behind the theory have no Packards or cars hard to find drums for.

On your new manual, how is the picture quality -- really good like those in the 55-56 manual posted on site or more like those in the 51-4 on site which came from a repro book. Those are pretty bad as compared to the originals.

"Arcing" is a standard part of good drum brake service, and especially important if the drums have ever been turned. When drums are cut the radius of the drum surface becomes larger than the radius of the linings and thus, until such time as enough material has been worn from the linings, only a portion of the lining contacts the drum, so you very inefficient brakes and also very prone of localized overheating of the lining.

"Arcing" is a grinding method that grinds the lining to match the diameter of the drum so that full lining-to-drum contact is obtained from the get-go.

Arcing is something that my mechanic will be interest in, I'm sure, if he hasn't done it already. Let's be clear, though, the LININGS should be "arced" rather than the shoes, correct?

I think an adjustemt will help the whole brake situation. I understand these brakes don't have self-adjusters, and they were set up as they are due to irregularities in the surfaces, and a conservative approach to how tight they were. "Arcing" could be part of the adjustment.

The photos in the Faxon repro are sharp and clear, as they were for the '47 Dodge manual I purchased a few years ago. Really beautiful work.

Thanks all!

LININGS - yes.