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Kevin;

If I remember correctly there were two designs in the routing of brake lines for dual master cylinders. One is the fore/aft plumbing, and the other is diagonal. I believe they were considered equally acceptable. If the replacement master cylinder does not have a residual pressure check valve then that part is frequently mounted externally. A system with 4 drum brakes would not need a proportioning valve. Now if that valve you have is really a residual pressure check valve then it is plumbed to service all locations that have drums, not disks . . . in your case with all drums there is no need of a proportioning valve, but there should be a residual pressure check valve. Remember that may already exist inside the master cylinder. Do you know what master cylinder you have . . . meaning original application?

dp

Took a quick look at the rear drums tonight. Disconnected the parking brake under the car and confirmed that the levers were all the way loose on the rear brakes. Confirmed that shoes are fully seated. Still does not fit.

My neighbor helpfully found a drum/shoe measuring tool and I checked using that. The inside diameter of the drums measured out at exactly 12". The other side of the tool checks the shoes, and they measured out about 1/16" too wide with no adjusting room. So it looks like I'm going to have to make some phone calls to see if anyone can grind the pads down.

I took a closer look at the master cylinder. It's a Wagner Lockheed FD 5031. I can't find any info for it online, but it looks almost identical to this one.

Besides being dirty, it "appears" to be in okay condition. No leaking that I can see.

There is a rat's nest of brake line, all leading to a junction box/proportioning valve. See the picture for reference on the lines:
1.) Master cylinder line 1 (in)
2.) Driver's front wheel (out)
3.) Passenger front wheel (out)
4.) Master cylinder line 2 (in)
5.) Rear (out)

I don't love it, but I'm out of time. My neighbor needs his shop back soon. So I'm going to get the rear's wrapped up, flush and bleed the whole brake system, mount the new tires when they get here and move the car out. After some brake testing I hope to get the car on the road to do some controlled testing of brakes, engine, transmission, cooling system.

Eventually I'm going to go back to the original BTV brake system and get the whole thing back to original. Man, I knew these brakes were going to be a hassle....yuck. But at least I'm learning.

-Kevin

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  Brake drum measurement.jpg (146.62 KB)


  Shoe measurement.jpg (152.56 KB)


  Master cylinder and rat's nest of brake line.jpg (196.98 KB)


  Proportioning valve.jpg (233.88 KB)

I think your doing great. enjoy following along

This is an off the wall comment/question about the total shoe diameter.

What if the Packard ‘star wheel’ adjuster is too long for the shoes that you are using? I’m not saying the adjuster is too long, but the shoe itself has too much material in that area. We know the thickness of the shoe’s web was too thick for the stock Packard adjuster, and you took care of that be thinning the web. If there was also too much material facing toward the adjuster, then the net result is a shoe diameter that will not fit into the drum. In that location of the shoe we need about 1/8 inch ‘more adjustment, that’s about 1/16 inch on each shoe, but 1/8 on each shoe would allow a bit of extra slack.

On to the photograph of the master cylinder plumbing entering and exiting the distribution block. I think that’s all it is, a distribution block with a ‘brake system malfunction’ switch. If either side fails a piston under the switch shuttles to one side and a dash light comes on. I think the geometry is such it will not automatically reset, but others may fill-in details. If the light is hooked-up it makes bleeding the brakes a pain.

dp

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Thanks! I'm also enjoying watching your progress as well.

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That's something I hadn't thought about. I don't have the shoes in front of me, so I can't check. Just going back and looking at pictures of them side by side, it looks like they might be slightly different in that area. I'll pull off one side and check it tonight. Perhaps a little extra grinding in that area will solve it?

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I don't think there's a light on the dash (at least I haven't found one), and I don't see any wires going from the distribution block. Good to know what it is, even though it won't be staying long-term.

-Kevin

Kevin;

Since the dual master cylinder design was introduced well after Packard had ceased production there would not be a warning light in your car. It looks like the folks that installed the dual master cylinder ‘grabbed’ the distribution block as a matter of plumbing convenience. One of the tenets in my profession would be that latent failures must be detectable by the person operating the equipment, especially if redundancy is used to improve the reliability of the product. The dual master cylinder was introduced to add redundancy, and hence reliability in the braking system, but if the average driver could not detect that half of the braking system had failed the accident/death rate would not be reduced to the extent possible. Enter a bright red light on the dash to help the average driver. Now we use lights and fault codes . . . not so much back then, just lights. Speaking of lights, where is the brake light switch mounted?

If you asked 10 Packard owners whether converting back to a BTV was a good idea, I’m sure you would have 20 or 30 opinions on the subject. Normally when a dual master cylinder is installed there are issues in mounting and pedal linkage geometry. Your MC looks like it is mounted considerably ‘higher’ than the OEM location. May I assume the pedal geometry has changed, and if so one of the variables in your decision is whether that change was accomplished in a professional manner? If the pedal linkage looks ‘bullet proof’, and the car has adequate braking performance after you get it back on the road, then I’ll be glad to add my 2 or 3 opinions on the subject.

dp

The brake light switch is mounted to a second distribution box down on the frame, closer to the original location for the BTV master cylinder. It works, and the brake lights come on instantly every time. Again, I don't love the setup, so that will likely have to change later...too many parts open up more possibilities of failure/leaks.

The brake pedal is a whole other problem. "Professional manner" it is definitely not. The brake pedal is out of some other car and is huge. I'm pretty sure it has full range of motion, so that is good. But the whole setup just bugs me.

I do have the original brake parts including pedal, but I'm not sure how the original pedal mounts. I'm not sure if the original mounting location was removed/modified to accommodate this other pedal/master cylinder setup. I also have the original BTV unit, but it looks like it's missing quite a few parts, including the master cylinder. I doubt it could be rebuilt.

-Kevin

Check out the service counselor article on installing the Easamatic kit in 51-2 cars.packardinfo.com/xoops/html/downloads/SC/SC-VOL26NO5.pdf The brake pedal location and installation is the same for 54 as is almost everything else in the article. The 54 exception is the 52 firewall mounted breather was no longer on the firewall but was incorporated in the top of the Treadlevac for 53 and later units. The photo shows the pedal side of a 55 bracket which used the same location.

The original power brake pedal has the brake unit mounted at the bottom of the arm for a ratio of 1:1. That was OK for the Treadlevac and its fairly small diameter long stroke ram displacement action squeezing fluid out of the cylinder but not good for the modern larger but short stroke pistons pushing the fluid. Typically modern piston boosters and manual systems need about a 4:1 ratio for power and 6 or 7:1 for manuals.

As the Packard power brake pedal will not work in stock form for use with a modern cylinder many brand x or aftermarket pedals or seriously modified Packard units such as was devised by Craig Hendrickson for his first ever install of a modern power brake system have been tried. The stock manual pedal will work for manual cylinders as long as a master can be found that side mounts directly to the frame as the original did. Mounting a modern dual cylinder if it needs extra brackets for front mounts and/or other conversions presents challenges in trying to line up linkage between the pedal and cylinder.

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  pedal bracket.jpg (178.73 KB)

Thanks Howard for the picture. That will come in handy later. For now I've decided to roll with the dual master set up as it stands. I've replaced most of the lines. Some were replaced previously when the dual master was put in. They appear to be stainless steel and incredibly hard to bend.


Not much progress unfortunately. I've called every brake place around and no one arcs brake shoes. In fact, most places said "what's that?". I've tried taking more off the web where the adjuster sits to no avail. I don't think there's any way I'm getting these shoes to fit without taking off a bunch of the lining.

So I'm just going to bite the bullet and order some new shoes from Kanter. Should have done that from the beginning. Live and learn.

-Kevin

You might compare your adjusters with those from Napa. They have adjusters which are labeled as self adjusting. Similar in looks and come in various lengths but have a smaller diameter and teeth on the adjust wheel. If the spring can still keep tension on the toothed wheel the smaller teeth in itself might not be too much an issue as long as a finer blade adjust tool can be used.