I recently purchased a 66 ford and would like to upgrade my braking system, without converting to disc brakes. What two reservoir master clylinder will replace the single master clylinder that came with the truck? Thanks

 

for a f100,I think 67 is a direct bolt on.

 

I would like to pitch my 2 pennys in here. I don't know why you want a double bowl nor what you expect from it. The disc brake upgrade is a serious safety improvement. It can save your butt. Adding a double bowl by itself is a design change not done with safety engineering.

I have been riding with the discs for 5 years now on my 66, I highly recommend them. I have upgraded the rear brakes too.

John

 

I'm also a big fan of the disc brake conversion. However, if you have your heart set on retaining those heavy, unreliable, useless-in-the-wet drum brakes, go for it.
A newer truck master cylinder will fit, as will a similar year (68-ish) Mustang from what I've read. IT MUST BE FOR DRUM BRAKES or your proportioning will be all wrong.

 

I disagree. The dual reservoir absolutely adds safety because, for example, if the front brake line blows, then you will still have the rears operating

 

take a look at the nhtsa's report. They feel that the dual master cylinder has provided a greater benefit than disc brakes.

http://www.nhtsa.dot.gov/cars/rules/regrev/evaluate/806359.html
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http://www.nhtsa.dot.gov/cars/rules/regrev/evaluate/pdf/809833Part1.pdf

i hate how links [don't] work on this site.

Quote:

How dual master cylinders work

Without dual master cylinders, a significant loss of pressure

in the hydraulic system due to a leak can result in a complete, catastrophic loss of braking power.

Moreover, when there is a slow leak that will eventually lead to a loss of pressure, the vehicle
does not send an early warning that can be easily understood by the average driver. The Indiana
Tri-Level Study of the Causes of Accidents suggested that approximately 2 percent of all
accidents in cars with 1960’s technology were caused by some type of catastrophic brake failure,
most commonly hydraulic failures.4


A dual braking system consists of two separate hydraulic circuits – typically split front-and-rear
in rear-wheel-drive cars, or diagonally in front-wheel-drive cars. Both circuits are activated by
the brake pedal through one master cylinder that has two chambers, called a “dual master
cylinder.” If one of the circuits fails, the other is still available. The car can be stopped from
high speeds, although of course not as quickly as when both circuits are intact. A second
important feature is that the dual master cylinder has a sensor to detect the relative pressure in
the chambers. If there is an imbalance, it activates a warning light on the instrument panel. It is
an unambiguous early warning that the brake system needs repair.5


Expected benefits Dual master cylinders should prevent many of the crashes involving
catastrophic brake failure, specifically those due to failures in the hydraulic system. Possible

exceptions could include certain types of failure within the master cylinder or cases where the

driver ignores the warning light. Since catastrophic brake failures can occur in fatal and injury
crashes, dual master cylinders ought to have an effect on fatalities and injuries. Moreover, when
brake failure in one vehicle results in a collision with another vehicle or pedestrian, preventing
the brake failure in that one vehicle will prevent the fatalities or injuries of every crash partner,
including the other vehicles’ occupants and pedestrians.

 

My response is going to set off a firestorm - but nonetheless here it is:

(Taylor 0987, please don't take this personal; this isn't about you. Junk science is a strong pet peeve of mine.)

This article is invalid. It is a perfect example of the junk science the government produces.

It is invalid because they are comparing two unrelated factors.

Factor 1: Dual master cylinders prevent total system failure. Disc brakes have nothing to do with preventing system failure.

Factor 2: Front disc brakes increase stopping reliability. Dual master cylinders have nothing to do with increasing stopping ability.

They have compared apples and oranges.

The only way to properly and accurately measure the comparison between the two is to conduct at least one of the two following tests:

Test 1: Compare cars with dual master cylinders only. One set will have dual master cylinders with front drum brakes. The other set will have dual master cylinders with front disc brakes.
(This test has been done, and the comparison is pretty incredible. Disc brakes far exceed drum brakes in stopping reliability.)
This test measures STOPPING reliability.

Test 2: Compare cars with single pot master cylinders only. One set will have front drum brakes and a single pot master cylinder. The second set will have a single pot master cylinder and front disc brakes. This test cannot be done without some special configuration for the hydraulic setup. It will never be done, it probably isn't worth it just to make a point.
This test measures HYDRAULIC FAILURE.
For the article refenced above to be accurate, this is the test which SHOULD have been done to substantiate the claims it makes.

In summary, there are only two claims this article can validly make;

1. The introduction of dual master cylinders reduced accidents caused by hydraulic failure.

2. The introduction of front disc brakes reduced accidents caused by ineffective braking.

They can ONLY state the percentages involved in introducing the two technologies. They CANNOT claim that one is more effective than the other, that the dual pot master cylinders are more effective than front disc brakes, because the two are unrelated in their functions.

Junk Science. It is everywhere.

Conclusion: If all you can do at this time is upgrade to a dual pot master cylinder, DO IT. You will reduce the risk of total brake system hydraulic failure.
For better stopping ability, upgrade to disc brakes.

Fire away guys, I've got my asbestos suit on.

 

Taylor0987 is correct in saying that the dual pot master cylinder is much safer than the single pot.

I think jowilker may have left out a word in his previous post, which caused confusion.
(John,please correct me if I am wrong)

I think he meant to say: "I don't know why you want ONLY a double bowl ....."
(emphasis mine)

Pockets: You can still get new and re-manufactured dual pot master cylinders for drum-drum brake systems. Front drum brakes were still used on F-100s up to '72 (my son's '72 had them) since disc brakes were not required until '73.
Pushrod length will be an issue you will need to overcome, though.
I recommend you take your single pot to the store. Ask for a master cylinder for a '72 F-100 4x4 and for a '72 F-100 2x4. Make sure to tell the parts people for a front drum system. Compare all three side by side.
I know the '72 2x4 will have a longer rod, but the 4x4 for a '72 might be exact.

Keep in mind you will need a proportioning valve for a drum-drum system. You can get one from the boneyard from a truck and possibly a Mustang, Galaxie and other '60s cars. Again, make sure you get the proportioning valve for a drum-drum system.

Check it out, and good luck. Keep us posted on your project!

 

Jowilker also might have left out a word when he said "Adding a double bowl by itself is a design change not done with safety engineering"

I agree with some of your criticism of those articles, Banjo. I shouldn't have bought into their conclusion so quickly. But it definitely supports that a dual MC is superior to a single MC.

I think Volvo sold some cars with a triple MC, one for each front side and the third for the rears

 

I forgot about those Volvo triple bowls!
Very funky looking. Mercedes did some of the same, at least in Europe. I saw several other European manufactured cars in junkyards in Germany as well. Not sure they had the same value added as a double bowl, though.

I know John Wilkerson, and he is a die-hard proponent of the dual-pot master cylinder upgrade.

 

Did you have to change the master cylinder to run the disc brakes? I am thinking about uprgading my brakes as well, ive got drums all the way around. I have to say though, the brakes seem to do a good job, not the best but they work good.

 

Yes, drum brakes and disc brakes use a diffferent master cylinder as well as a different proportioning valve.
When upgrading to discs from drums, you must use the correct parts.

 

isn't there something in the MC for drum brakes that keeps a slight bit of pressure against the slave?

 

Yes one system keeps slight static pressure and the other doesn't.
I never can remember which one.
Either way, the hydraulics for one are incompatible with the other, so you have to use the right master cylinder and proportioning valve.

I used jowilker's suggestion, and bought an entire junk truck. I harvested all the parts, including the pre-formed steel brake lines, proportioning valve, pedal, master cylinder and power brake booster complete with mouting bracket, disc spindles, and the calipers to use as cores.
I haven't done the upgrade, yet, I am waiting on a few details to be resolved, but I have everything ready.
I have new rotors and bearings, new king pins and front brake hoses, and will turn the old calipers and booster in as cores when I actually do the work.
I'll use the switch from the donor truck as well to activate the brake lights.

 

Thanks for all the information guys. It,s nice to know that there is alot of information out there for a newcomer like myself. I may go to disc front in a few years but right now budget and ability will win out.