Packard Forum Index » V-8 (1955-56)

I have been researching on different options besides using the factory Treadle-Vac system on my 56 400. The main problem with converting to a modern type master/booster is the 1:1 pedal ratio. I do not want a master/booster on the firewall due to it not looking original. I want to keep it in the toe board area where it is from the factory. Last night while researching, I came across a product by the ABS Power Brake company in California. It mounts in the same holes as the factory Treadle-Vac and has an additional linkage to compensate for the 1:1 factory ratio to increase the ratio to a more modern 4:1 or so. The kit in the link below is installed on an Oldsmobile or Pontiac I think, however it is the same concept as the Packard. The kit they are using uses an electric booster, but if I have to use a remote booster, I would prefer a vacuum type. In the article they also convert to disc brakes, which I don't know if I will do or not, however the company offers a disc brake kit for the 56 Packard. Has anyone ever used this type setup, and would it work on my 56 400?

Here is the link to the article with the Treadle-Vac conversion.

Brake System Upgrade from Treadle Vac with ABS Power Brake Inc.

The linkage to increase pedal ratio would make all the difference if it is thin enough to be done on a Packard. A big problem on using anything with Packards placement of the BTV in the original location is it is tucked in the frame and the length of the space available is limited by the location of the steering box. If the linkage is thin and can be positioned so one of the shorter electric masters will fit low or maybe angled to bring one of the relatively thin electric masters up above the frame rail an inch or so to clear the steering it would be a welcome conversion.

I know of a couple of the ElectroBoost systems installed low and using the 1:1 ratio. On those the power unit is turned up to high boost to compensate for the low ratio. I never saw any feedback from those conversions to know what happens if the power unit fails and stored energy is exhausted. With the 1" piston on the master at 1:1, I suspect the stopping ability would be as dismal as it was with the modern vacuum booster setup most conversions have used when tried in the original location.

More information on the linkage would be greatly appreciated if you have it. Not a lot of detail in the article and I don't see any photos or mention of it in the ABS website info. Wonder if it is made by someone else or custom to that specific car application.

There is a picture of the linkage in the article. It is attached where the Treadle Vac attaches originally. The remote master cylinder then attaches to that. I think this may be the type system member “buddyfromvb” used on his car. I think ABS makes it. I’m going to call them tomorrow to see if they still make it.

I saw the photo in the article but not on ABS site. What I am concerned about is that the angle of Packards floor points the master down into the frame and steering box. It is a straight shot and if the linkage piece is thin enough that might work with a short master. If not, wonder if it could be mounted differently or maybe some kind of angled piece could be added toward the bottom of the linkage bracket to tip the end of the master up to clear the steering box or let any tubing connecting on the sides clear the frame.

I’m going to call the company tomorrow. If I can make it work, I think it will definitely be a good idea. On my 60 Chevy, I had to put shims under the bottom two bolts of the booster/master to tilt it up some, might could do the same on the Packard if it will fit.

I know in some quarters the Treadle-Vac is looked at as unreliable. I can tell you definitely that is not the case; when I bought my 1955 400 back in 2003 the car slammed to a stop when I mashed the brake pedal to the floor. The problem is incompetent rebuilders out there (like white post restorations). Send that unit to Ross Miller he will fix that unit right and it should give you many more years of service.

My Treadle-Vac works fine on my car, and I check the fluid every time I drive it. I’m just not a fan of the single master cylinder. I live in the mountains and we have lots of traffic here these days. I’d rather have something that I can rely on.

Please keep us appraised of what you find! I am interested in more information of this linkage, so if the company is willing to give some dimensions and angles that would be fantastic.

My only beef with Treadle-Vac is there is no vent between the cylinder and the booster, so if the unit develops a leak the results are catastrophic. The compensator may look Mickey Mouse, but when it has the correct materials does not seem trouble prone.

On modern cars they used to have a vent port that would allow such fluid leaks to vent for easy detection. Later the Vice-Presidents for Customer Dissatisfaction put out a memo telling the engineers to fix that, so now faulty master cylinders will fill boosters with brake fluid and ruin them. That's what is called progress.

If you watch Jay Leno's video on his Caribbean he talks about driving down Mullholland Drive and overwhelming his brakes. That is the favorite road for Hollywood chase scenes.

However, if you try to drive those Packards in a reasonable manner you are at the mercy of all the jerks on the road today. My modern car has the flasher switch almost finger reach from the steering wheel which comes in handy when these idiots decide to stop dead from high speed on the expressway. If they aren't tailgating and looking at Twit they are slamming on the brakes to rubberneck at state troopers.

Quote:

On the BTV units of that period there is a vent called the relief port which connects the reservoir chamber to the space between the hydraulic and vacuum seals. In Packards case two things seem to have happened to block the vent on units used after 53. On the first model BTV Packard used, the vent port opening was lower in the reservoir and the Packard flat lid did not block the opening. Later versions extended the casting containing the vent port opening flush with the top of the reservoir edge.

It appears other mfgs using the later BTV had a stamped lid with a bulge or channel which was directly over the opening so air could be drawn in if there was a vacuum leak or fluid could escape if a hydraulic leak. For whatever reason Packard stuck with their original flat lid and in combination with the gasket used for the other lids, the port opening was well blocked.

At some point a BTV version must have been released with no vent. Maybe the hydraulic reaction version of the late 50s?? Packard never used that version but a no vent casting is the way the repro castings are being made today. That could also be the reason some rebuilders were apparently filling the relief port on the early units with silicone during their rebuilds -- in effect totally blocking it for all lids. When the port is blocked a leak at either seal means fluid is either forced by hydraulic pressure or sucked by vacuum into the vacuum side.

The flat cover and gasket can be used without issue if time is taken to slot or remove the gasket material in the area that goes over the solid part of the casting containing the port opening. That small clearance space gained between the opening and the lid allows fluid to escape or air to be drawn in even with Packards flat cover..