Brakes - Wives Tales & Misconceptions

[KULTULZ]

Originally Posted by 56sedandelivery

Geeeze I have a lot to figure out.

How are you planning to do your '56?

[56sedandelivery]

Originally Posted by KULTULZ

How are you planning to do your '56?

Well though disc/drum was way to now not so sure. Thinking about 4 wheel disc but that probably open up a whole nuther can of worms. Car will be mainly street crusier. Now if I can just find someone local that can do a door reskin, Do not think I am that good of welder to tackle it myself

[KULTULZ]

4W DISC is a little extreme (IMO) unless you have a show car and open wheels to see the install.

FRONT DISC/REAR DRUM will bring it down quicker,

[miker98038]

56sedandelivery, FWIW (and ignoring the above discussion). All the front disc conversions I’ve seen for the 55-57 thunderbirds just seem to work pretty well. Typically a Mustang or Fairlane disc/drum master and Fairlane caplipers. Granada rotors with the center turned down to fit the early wheels. I’ve owned them, they work. If you add power, it’s the factory style booster, and only used on the front disc. There’s a spacer for the bearings that move the front wheels out about 1/8”, but that’s no a problem with anywhere near stock tires.

An acquaintance on SoCal has a set on his 56 Vicky that he bought from Prestige Thunderbird for his 56. After visiting them and getting all the specifics. Long time knowledgeable racer, he’s happy, so they’re ok.

As Kultulz mentions above, 4 wheel disc get more complicated. You don’t want to hear the time and cost involved at that point. I know, because mine work.

[RKS.PA]

I know this series goes back to mid-2022 and is about disc conversions and it's really definitive...thank you.

When I first got my '56 T Bird about a year ago, the stock booster brakes worked okay, with a sudden lock up at low speeds. So, opened up the system and the fluid was the color of a stirred up mud puddle. Flushed the system completely, replaced the line from the MS to the booster, and replaced the booster vacuum hose.

Now, the brakes work great. Don't think converting to from discs would improve much for me, considering the effort and expense.

[KULTULZ]

Sponsored Links (Register now to hide all advertisements)

So, opened up the system and the fluid was the color of a stirred up mud puddle. Flushed the system completely,

THAT'S GREAT! The 1955/56 FORD and period BIRD brakes were more than adequate, other than road racing (or a THUMPER ENGINE is not installed).

Now don't take this wrong, but if there was that much trash in the system, you might want to consider rebuilding the MC and wheel cylinders as corrosion is sure to follow. Don't forget the valve on the booster.

Brake fluid needs to be changed at the minimum of every two years even if the car is not driven often.

[KULTULZ]

- EXCERPS FROM POST #45 (ABBREVIATED) -


- 12 JAN 2024 -

Originally Posted by KULTULZ

The below from a BRAKE TECH FAQ website discussing the GRANADA swap

To Wit -

When you're getting the spindle assemblies at the salvage yard, don't forget the distribution block. Most any post-1970 ford distribution block for dual circuit braking systems will work.

The unit has a pressure sensing diaphragm which, when detecting a pressure drop, will close off fluid flow to the dropped circuit. This will allow you to still have either front or back brakes. Take the connector and a partial strand of the wiring, as you may wish to hook up a "brake warning" light later.

Above Is Incorrect -

One myth that often pops up during conversations is the misconception that if the spool in the pressure differential valve gets pushed off-center due to (for example) a brake line failure, it seals off the bad side, allowing you to still have brake pressure on the good side. This is incorrect! It is merely a warning system. The ends of the spool are turned down to allow brake fluid to pass when it is pushed to one side.

If the spool was designed to cut off the brake fluid to the side where the pressure has dropped it would seal the fluid between the master cylinder and the distribution block. This would cause the brake pedal to be rock hard and you would have no brakes at all because the trapped fluid would not give.

The dual master cylinder is the safety feature that allows pressure at the good end. There is nothing inside the pressure differential valve to replace when rebuilding except for two special o-rings and a crush washer.

Source - PHOENIX BRAKE SYSTEMS

When you're getting the spindle assemblies at the salvage yard, don't forget the distribution block. most any post-1970 ford distribution block for dual circuit braking systems will work.

EDIT - Wrong again. Each PPV within a combination valve is calibrated for the vehicle it was released for.

The unit has a pressure sensing diaphragm which, when detecting a pressure drop, will close off fluid flow to the dropped circuit. This will allow you to still have either front or back brakes. Take the connector and a partial strand of the wiring, as you may wish to hook up a "brake warning" light later.

A diaphragm? It is a pintle (edit - actually shuttle) (and it will not block cross-flow). When the shuttle valve moves to one side or the other, it initiates an electrical switch (2B264) that will illuminate a warning lamp on the instrument panel (if so equipped - 1967/ ).

I think the writer is describing the PDV (pressure differential valve) as FORD did not actually release a combination valve (an assembly consisting of two or more individual braking valves) until 1972. PDV, PPV and metering were separate. Actually the PDV at that stage was included in a distribution block (or, it can be said the distribution block was actually part of the PDV), hence one thinking it was a combination valve)

As for the PDV, if one does not want or need the warning lamp feature, actual distribution blocks are available for a neater appearance.

While this particular tech write-up has a 2001 date, it is still online and should have been corrected (IMO of course).

[KULTULZ]

Originally Posted by miker98038

56sedandelivery, FWIW (and ignoring the above discussion).

I heard that Mikee ...

[KULTULZ]

- BRAKE QUESTION ON A 1954 MERC -

https://www.fordbarn.com/forum/showthread.php?t=335072