Packard Forum Index » Modification Discussion

84'ish Honda Civic power brake set up comes real close. It has a 13/16 piston which is a just a bit too big for the 1:1 ratio. but the length of piston travel is just barely adequate. The unit fits into the space just fine. But the power unit and piston travel is almost too short. The pedal gets real hard.

My mechanic tells me I need a new brake master cylinder for my 1955 Patrician. He says that the Treadlevac unit appears fine (I had it rebuilt 15 years ago and it has only about 500 miles on it). My mechanic says that special tools and expertise are required to disconnect the old master cylinder from the Treadlevac unit and to attach the replacement, which I am thinking of ordering from Max Merritt in Indiana. I live in No. California but could ship the parts to anywhere in the country if someone could tell me a shop that can do this work.

Actually, the TreadleVac unit is the hydraulic and vacuum cylinders combined. What I understand, then, from your post is that your mechanic feels that the (vacuum) power assist section is working fine, but the (hydraulic) master cylinder requires repair or replacement.

The original special tools are really not essential, but when needed, they can be fabricated rather easily if one reviews the procedure in the Packard Service Manual (archived here for your viewing pleasure). I've overhauled those master cylinders in my home garage with little trouble. The outlet fitting can be a bear to get loose; as such, it is best done first, while still attached to the vacuum cylinder - as shown in the factory shop manual.

Often, the hydraulic piston has become pitted and will quickly ruin new hydraulic seals, but a new piston could be fabricated by a decent machinist out of steel or even stainlesss steeal (the latter alleviating the need for hard chrom plating).

However, the condition of the compensator port valve spring is critical - yet not included in any kit. Corrosion from even small amounts of moisture absorbed into the hydrualic system over the course of many years will take its toll on this part, too, and failure of that spring will result in a complete loss of hydraulic action.

In the absence of off-the-shelf replacements for such parts, one need look to a reputable and competent rebuilder who specializes in servicing the unique technology of the Bendix TreadleVac and has reproduced the essential parts. They will want the entire unit and go through it completely. Most people seem to favor Ed Strain, though I've not personally done business with him. A quick search on Google showed the following address and phone:

Ed Strain
6555 44th St, Unit #2006
Pinellas Park, FL 33781
800-266-1623

Are u using DOT5 (silicone) or Dot 3 brake fluid?????
I would not expect rust in the system unless the car has been subject to extreme moisture conditions. Hi moisture is NOT exactly N. Calli climate conditions or is it???

500 miles in 15 years????? Did the car set outside any during the 15 years??????? What has been the storeage conditions for the car?????? Or was the 500 miles of driving thru creeks and rivers or Tsunami floods or anything like that?????

When u get the master cylinder off then take it apart. IT's REAL EZ to disassemble. Show us pics.
U can call me and we'll walk thru the disassembly of the cylinder. Phone number on request by Private message.

U can still send it off to the rebuilder in a box assembled or disassembled. Basically u're sending them a core anyway.

Look at the brake fluid. Is it dirty looking????? tell us what u did about the rest of the brake system 15 years and 500 miles ago.

Thanks for the great info, Brian! I called Ed Strain
but it was not during hours. I will call back and get
a quote. Meanwhile, Max Merritt quoted $395.00 for
entire master cylinder/ Treadvac assembly + plus a $150.00 refunable core charge.

PJ

FWIW, i saw a 1956 t bird at a car show this evening that had a standard non power master cylender and a remote booster. the gentleman said it was similar to the one used on that car originally (his had not been equipped), and was also similar to a volkswagen unit. He, unfortunately could not provide more information as he had done the conversion many years ago.

The booster he had seemed small enough to be tucked into the fenderwell where our stock vacuum resivour is.

Perhaps this coupled to a small manual master cylender like the honda one mentioned earlier in this thread would be functional?

Title: Packard Easamatic Brake Demonstration
Creator: Paul Slantis
Date: ca. 1951
Identifier: 000059.PIC
Rights: Copyright Not Evaluated
Place of Publication: Pittsburgh
Description: A group of people is standing around watching a demonstration of Packard power brakes.


As a side note ...
Pic #2 shows a beautiful lady, who presumably worked for the PMCC marketing department. We have seen her pictured before (but I don't know where).







sources
#1 - University of Pittsburgh
#2 - University of Pittsburgh
#3 - eBay, item number 382315169675

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Yes, the young lady is indeed lovely----but check out the gloss on the paint on that Patrician nearby!