Packard Forum Index » V-8 (1955-56)

Maybe i missed it but what car or application is the master cylinder mounted to the toe board directly under the pedal from???

Keith,

packarddaaveuk has a '55 Four Hundred Hardtop Coupe.

Let me rephrase the question:

What car application is the master cylinder originaly used on. Or what part number do i ask for at the auto parts store.

OR, if i go to the auto parts store then what do i ask for???

I don't think finding a master is too difficult and his particular one may be something for a car never brought over here so not available anyway. This site has multiple small bore masters that look to be very similarcarshopinc.com/advanced_search_result.php/keywords/master%20cylinder/page/1 -- page 3 shows a Tilton cylinder with a 5/8 bore with remote fill and almost any street rod or drag site seems to have something similar.

What I have been looking for on and off is a remote booster setup. At a quick search, those don't seem to be that plentiful new unless you want electroboost or hydroboost.

Bendix is out-- although several will rebuild Hydrovacs, wonder if that would be a good choice even if new. Lockheed seems to be almost in same category here with a few mentions of the Jaguar units but haven't found it for sale yet at anything other than Jaguar and other English car sites. That kind of makes you wonder if it would be a wise move on that unit for future parts. Midland used to have something small Ford used but now seems to be mostly in the big truck business. There is a fairly large vacuum remote boost unit on Chevy sites that mount in the trunk. Otherwise, so far I have not found much.

The master cylinder used is not from any specific vehicle they are used by kit car builders and the like. The new booster was sourced from ebay UK where they are still available. Cost including shipping in UK was approx 100 pouds ($150) they are also available from kit car aftermarket parts suppliers but the place I got mine from was an MG specialist and cheaper. Its not possible to fit a dual master cylinder to this booster but it states in the instructions that if a dual master cylinder is used at the pedal then 2 boosters are required... things start to get a bit complicated then so I stuck to the single circuit braking for now..
This set up is still at the trial stages and is not proven so I would not advise anyone to buy the same just yet. I am still concerned as to if the 1:1 pedal and 3:1 booster will be powerful enough. The booster is as used on Jag Mk 2's which were a heavy car but still not as heavy as a 55 Packard.

The website HH56 pointed to above shows a 5/8 master cylinder. It also shows a push type slave cylinder. Does not indicate diameter of slave tho.

So why wouldn't the following set up work:

1. Use the 5/8 master cylinder mounted at the toe board.
2. Obtain a 1" or maybe 1-1/4 inch push type slave cylinder.
3.Obtain a readily available modern power unit and 1" master cylinder assembly - for example a 1996 Explorer master cylinder and power unit.

Mount the 1" slave to the Explorer power unit on the PEDAL side of the unit. Mount the Explorer master cylinder to it's usual place on the front of the explorer power unit.
This makes a 3hree unit assembly that can be remotely mounted.

Run a brake line from the aftermarket 5/8 master cylinder at the toe board to the 1" slave of the power unit assembly.

The 5/8 master cylinder to 1" Slave clinder will give the HYDRAULIC EQUIVELENT of about a 2.5:1 pedal ratio. Maybe a 1-1/4 inch slave would be better.

Of course there is always the stroke of the slave and master cylinder combination to consider too.

DaveUK.

If the remote mounted reservoir supplies the ENTIRE brake system then it seems to me that it should be mounted HIGHER than the power unit assembly on the fender well.

DaveUK write:
" I am still concerned as to if the 1:1 pedal and 3:1 booster will be powerful enough."

I am not familiar enuf with that particular power booster and cylinder that is mounted to the power booster arrangement to answer or make any calculations for that question.

PV8. the booster scenario you mention has been done. There is a kit available on some of the Chevy sites--but is large and almost has to go in the trunk. There is a better picture on another site, but can't remember where right now.

There is also a site that has a lot of good information about ratios and calculations.deanoshiro.com/brakes/brakearticle.html#booster

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HH56. Ok. Thanks. But what is it that u don;t like about that set up u pictured above???? Seems to me like it's the only choice for those with factory air. Maybe too pricey??? I don;t know. It mite be the only option.