Re: 1953 Patrician: has anyone updated from Treadlevac to modern 2-chamber mstr cyl?

Posted by HH56 On 2022/7/13 23:11:59

As Tim said, pedal ratio or location needs to change to get the modern systems to work satisfactorily. The reason the BTV works with the 1:1 ratio is it has an approx 3/4" diameter solid rod that moves thru the fluid and via the closed cylinder displaces the fluid and sends it out with greater force rather than what is possible with the modern masters 1" piston that pushes a volume of fluid ahead of it. I did some tests a few years ago and found there was almost a 2 times increase in pressure with the BTV. With no vacuum, 100 lbs pressure on the pedal resulted in almost 200 out and with vacuum, the same 100 lbs in increased output to almost 500.

There have been any number of conversions on V8 models but the only ones that have kept the new booster/master in the original location have had extensive pedal mods that raise the pedal higher off the floor and move it downward. This mod was developed by the late Craig Hendrickson in one of the first documented changes to a modern master. The relocated pedal is very noticeable but it does work. Moving the new booster/master up to the air vent hole has allowed a less drastic modification of the pedal or even using pedals from another car to get the proper ratio but still maintains almost the original look and position. Downside to that approach is you lose the drivers side air vent.

There are some interesting photos of the 56 that is in todays bring a trailer post. That setup is located high on the firewall -- almost to the top. It seems to clear the relays on the fender and it has what appears to be the original pedal but with a different mounting. Another poster has asked the new owner if he could take some more photos on that setup.