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My '54 Convertible had the dreaded Treadlevac master cylinder failure which sucked all of the brake fluid through the power booster. Luckily it was in the garage. Rather than rebuilding, I'm considering a Wilwood tandem dual chamber master cylinder with remote fill. Any thoughts on this? How would one select and mount it? I'm planning to keep the drum brakes. Thanx for your help, Les

Why not just rebuild the Treadlevac? It's a good system and easy to rebuild.

Because I'm nervous about the sudden failure mode and I'd like to upgrade to dual circuit brakes. Rebuilding the Treadlevac is always an option.

The problem with installing any modern system is pedal ratio. Packard placed the Treadlevac at the bottom of the pedal for a 1:1 ratio. 100 pounds of foot strength equals 100 pounds to the master.

The Treadlevac has a solid approx 5/8" diameter rod which moves in a fairly long stroke into a closed cylinder and displaces a volume of fluid out to the wheels equal to the rod volume that was inserted into the cylinder. That arrangement can cope with the 1:1 pedal ratio because the rod in effect very efficiently squeezes the fluid out of the confined space with the booster section adding to the foot force.

Modern masters use a fairly large diameter piston to push fluid ahead of it and out to the wheels. The larger diameter piston needs less stroke for the volume but because of the larger surface area needs more force to push the fluid out in an adequate strength. The piston gets the additional force by using a pedal ratio of approximately 4:1 along with the booster to provide the additional force if a power brake system or a ratio of approx 6:1 if strictly a manual system. 100 pounds foot strength on a power brake system equals 400 pounds plus whatever the booster adds or if a manual system, 600 pounds to the master.

In order to get the additional pedal ratio the master must be moved from the bottom of the pedal where Packard placed it and mounted so the connection between the pedal arm and the master unit is higher up on the pedal arm. The closer the connection is to the upper pivot equals a higher ratio but shorter stroke so there is a tradeoff in finding the best location. Many have installed modern universal boosters and dual masters in the opening for the air vent or even higher on the firewall and made custom pedals to work with the chosen location. Others have kept the original bottom of pedal location but have severely modified and relocated the pedal components inside the car to provide the additional ratio. Neither option provides a stock appearance.

You can do a search on the forum for BTV or brake replacement or modern brakes or several other similar titles for various threads where people have documented their approaches. The air vent location seems to provide the best overall looking and possibly easiest to mount arrangement but does sacrifice the vent function.

Would fitting a non-power brake pedal assembly and then adapting a modern two chamber master cylinder to it work? Seems there should be room for the conventional pedal assembly and MC. I know this may not work with the TL equipped '55 and '56s. Just a thought. JWL

I believe a few have done just that to avoid hassles of mounting and looking at a modern booster. Manual brake pedal setups for the 54 and earlier are probably easier to find than 55-6 units and I believe the holes are in the frame near the steering box for the manual Packard master. Probably need an adapter plate to match the frame holes to a new Wilwood or a universal dual master mounting but with a pedal assy in hand, the required new mount and linkage should be a relatively easy project and is more hidden compared to the power unit.

All the technical issues that Howard mention about converting aside, these are not prone to sudden failure and I've ever had it happen in over 40 years of driving Packards with Treadlevac. Not that they haven't worn out - they have - but not suddenly and when it did happen it was always from lack of maintenance on my part. One is supposed to flush the brake system regularly but few people do. To me, such a conversion is a waste of time when the Packard had good engineering to begin with.

Having said that, if you decide to move forward with the project if sure you'll receive all the help and technical support you need from the kind people here so no worries in that regard. It might even be a fun challenge so I don't mean to discourage you from trying if you're keen on it. Whichever path you take, I'm sure you'll enjoy the results.

Thank you to all who have taken the time to respond. I am not looking for a major project at this time. I was under the impression that this conversion had already been accomplished and that the know how to do it was already out there.

So I've decided to get the Treadlevac rebuilt. Any recommendations for someone to do this?

One of the pluses of the Wilwood is the ability to add remote fill. Can this be done with the Treadlevac?

Thanx again, Les

Here where I live there was a shop that did it but that was decades ago and they are long gone. Since the Treadlevac is easy to rebuild yourself, that's what I do now. I typically just get all the new parts from someone like Kanter including the diaphragm and have at it!

Kanter can do BTV rebuilds or sell you an already rebuilt unit in exchange. Ross Miller in Maryland is another excellent choice for a rebuild. He is a frequent poster so maybe leave him a PM to check his availability. Ed Strain was another but not sure he still does them. I seem to recall someone posted that he might have sold his business so perhaps someone can confirm if he is still a possibility.

One of the pluses of the Wilwood is the ability to add remote fill. Can this be done with the Treadlevac?

Yes. There is one commercial kit I know of that is compatible with the BTV and there may be others. Here is an address for the fellow which sold the kit. Been a couple of years since it was posted but if the info is still current you might try to contact him for more information. I believe there are photographs and details of the kit in Big Kev's project blog but no idea where to suggest you start looking. Kev's blog is over 200 pages so it may take a while to find it.

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