Stovebolt.com Forums The Shop Area Driveline Double Master Cylinder

The single line master and original setup in my 2 ton does just fine, it's rated at 16,000 lb. gross, I'm not even running the Hydrovac yet, just manual stock hydraulic. I did pull the booster off the truck to get identification so now on the hunt to get it rebuilt or swap it.

"What would you guys do in my shoes?"

Not knowing much about how your truck is configured and your fabrication/engineering skills, I would advise going to people who specialize in brakes.
In my area (I have no idea how good they are):

MASTER POWER BRAKES
110 Crosslake Park Dr.
Mooresville, NC 28117
1-800-472-4181
info@mpbrakes.com

People have converted to dual non-power master cylinders on drum-drum trucks using newer generation master cylinders. Disc-drum started around 1971 and for this master cylinder you would need a proportion valve. If you have a drum-drum system, compare the size of your wheel cylinders and find/determine which master cylinder works best for those sizes.

I don't like giving advice on steering and brakes systems because they are extremely important for safety reasons.

I appreciate the advice. I thought it was a no-brainer to go with the dual cylinder system, and the dual cylinders come with the booster and proportioning valve, so I was pretty much sold on that system. One thing to consider though is the people telling me I needed the dual system were the ones selling it!

But these posts have got me to thinking. The original single cylinder system is not junk.

Thanks to all who replied.

I'm always just a bit suspicious of somebody who promises to solve all my problems by selling me something! He just might not have the purest of motives. That's especially true of the guys with the IFS suspension systems!
Jerry

Copy and paste:
Wagner Electric invented a dual-cylinder brake system in 1960. This system had a dual master cylinder separating front and rear hydraulic lines. In other words, if one line developed a leak, the other line could still work, and your brakes wouldn’t completely die. This safety measure was mandated by the federal government in 1967.

I have my own opinions on why the USDOT ruled a dual reservoir was needed.
*) There was no national speed limit until 1965 when the speed limit was set to 70 mph. Speeds were increasing.
*) Sometimes a lack of manufacturer's required periodic braking system maintenance (originates with DOT3 (hydroscopic fluid), moisture, rust and leaking seals).
*) More panic braking (braking system stress).
*) Vehicle speeds were too fast for our brains to react and downshift and/or use parking/emergency brake (instinctive reaction).

It makes no sense to pick out just one classic/antique part and worry about it's effectiveness (safety wise) and overlook the plethora of other parts. If you really want to get serious about it, our old trucks need modern brakes, a modern suspension, modern steering, crumple zones, driving assistance tech, video cams and airbags just to be safe in modern world of driving.

When I'm in my 55, I like to pick roads less traveled and slow down.

I like to pick crowded roads and slow down- - - - -everybody else is so friendly- - - - -they honk as they pass, and tell me "You're number one!" I just wish they would use the proper finger!
Jerry

1963, my bride-to-be was driving our 55 BelAire on a steep downhill toward a stop sign at a busy 4-lane. NO BRAKES. Fortunately she was able to thread into and through the 4-lane traffic without incident. Somehow one tailpipe had shifted and was rubbing on the brake line and had actually worn it through so there was no pressure. Granted, this was on 17 year old me for a poor installation of the tailpipes. But stuff happens. It made me a believer of the dual brake systems when they became generally available. I have upgraded both of my toys to dual systems even though they came stock with single master cylinder systems. I don't see how they are less safe than with the original systems. My 2 cents.

Mark

War Eagle, I agree with Mr. Lincoln. I have single reservoir systems on 6 of the 9 vehicles I own and have never had a problem. It doesn't even cross my mind as being "unsafe". The '56 Cadillac has been a daily driver for 20 years - rebuilt at the time of purchase. They're the best brakes on any vehicle I own - 12" drums with 3" shoes all around.

I'm not aware of any state that requires antique vehicles to be retro-fitted with seat belts. If they weren't required when the vehicle was built they can't force you to put them in.

One of the best reasons to install lap belts in a vehicle is to keep you behind the wheel at all times. It's pretty easy to slide around on a vinyl bench seat when going around curves or in a skid.

Mark you made a good point and provided an excellent example.

Please explain the steps you took to select the correct dual reservoir for your cars/trucks.
Sorry to put you on the spot.

My two toys, a 56 VW beetle and a 59 Fleetside long wheel base. On the VW it is fairly common practice to use the system from a later Beetle. Its been several decades but as I recall I used a 67 beetle master cylinder. I also changed the drums to larger size as the early Beetle brakes were not great.

The 59 is a mixed bag of parts with larger drums in the rear from a 69 GMC and front discs from a late 70's full size Oldsmobile. The Master cylinder and proportioning valve match a late 70's full size GM car, but using an 8" dual diaphragm booster because of space limitations. .

In both cases I just used combinations of parts that were similar or identical to those in later vehicles that originally had the dual system. The bug does not stop as well as i like and may eventually receive a front disc system, but the truck stops and tracks very well. I don't think it is rocket science, and the proportioning valve needs to either be adjustable or one that is from a similar weight vehicle with a similar brake system. Proportioning valve may not be needed for a drum/drum system.

This worked for me and both vehicles stop better than when they were born and with less pedal effort. Your mileage may vary, I am not advocating as an expert, just sharing my experience.

Mark