I have log been a proponent of pedals through the floor and I love not only the better arc you get but also the thump of a floor pedal hitting the floor. I have done 3 of my own this way, and even when I set up a '63 Falcon with disk brakes, I did my firewall masters with two unboosted masters. First of all you only need good engineering, not boosters, and you do not need any OEM parts from the masters to either front or rear. Any master going to a drum brake needs a residual valve which is built in to a stock M/C for drum brakes. The reason boosters have to be used with a stock type disc/drum master is because the piston is too large a diameter to allow reasonable pedal pressure.....

Here is a picture of the master cylinder mounting in one of my chassis I built.We have taken the 30 year old technology of dual master cylinders and applied it to this chassis. We used two 3/4 master cylinders with an out put pressure of 1359 psi each. This special mounting bracket mounts the master cylinders one on top of the other taking only 2.5 inches of width along the frame. The balance bar system allows full adjustment of the pressure balance and the remote fill eliminates the residual valves. This space saving feature provides additional room for your exhaust system. The deletion of the power booster also eliminates the need for vacuum.





[IMG]file:///D:/Pictures/50cpu_brakes.jpg[/IMG]
Before I ever saw this article, I made my own balance bar and used two cylinders mounted on a firewall plate (because the firewall was not strong enough for two cylinders). The balance bar connected to the brake pedal linkage. On my Falcon with Bendix sliding caliper, I needed a 3/4" piston, and for the rear, I needed a 1 1/2" piston (drum brakes) and I used no residual valve because I got about 3 psi from the height of the master cylinder which on drums is to keep some pressure in the rear brake line to keep the piston cups expanded in the wheel cylinder. I had an adjustable proportioning valve in the rear lines.

I always figured on doing a 55 or 56 F-100 this way and finally did about 2 years ago. The stock pedal, when used without a clutch, lets you bolt the brake pedal to the shaft, and use the clutch lever part of the clutch linkage to bolt to the outer part of the shaft and lets you mount the masters on the outer part of the frame, where it looks like this, if the stock gas tank is not against the frame on a 53-55 or if it is a 56. You can also box the frame and mount cylinders on the inside of the frame. These master cylinders have reservoirs that can snap on the cylinders (not with this kind of mounting) or connect with a line and remotely mount. Cool, eh?

Alanco

 

getting ready to tear into my 53 { it's my daily ride period no matter what } this winter to fix some things that need it and update the brakes is one of them . im , no matter what brake combo , gonna stick with it under the floor as i like it there outta the way .

 

Alanco, the links to your pictures did not work for me but I'm intrigued by your post. I also have been pondering this question and I like the "clunk" of the petals through the floor. Can you elaborate and maybe create a gallery so we can see what your are talking about?

 

I opted to keep my master cylinder under the floor, but I upgraded to a Corvette style dual reservoir with a Mustang booster. I added the remote fill so I can check my fluid level and add as needed from top side. Truck is still not finished but the braking system is and it looks and works great sitting in my shop. Ultimately though it's really personal choice. I just like the clean look of an unclutterd firewall.

 

AAhttp://www.hotrodheaven.com-tech-chassis-images-50cpu_brakes.jpgAA

This is the URL for the missing image. Ignore the AAs at the start and finish. They are there due to editing codes built in to the forum software that is pretty stupid and do not allow me to post a URL directly. It is old fashioned partially enabled Visual Basic code that does not allow direct pasting of images. It is maddening in the first place, and doubly so if you are used to modern websites and blogs. There is an article attached to this image. It is an outstanding brake article that has only a couple of typographic errors.

This is a custom framed hot rod, but it is easy to see how easy it applies to any underfloor pedal. I will have a picture in 3 or 4 months of my current '53 F250 flatbed 4 x 4. Discs on front, drums in the Dana 60 in the rear. Front brakes will be 77 Ford Dana 44 Hi Pinion F-250 with 8 lug hubs. (Bendix Calipers)

This forum is so hard to put images in, unless you post them somewhere with a URL, such as in a gallery on this forum or on a website, that just send me your e-mails and I will send you the images by e-mail. I can't send you my e-mail address here or I will be spammed to death, but you can send me your e-mail addresses through forum e-mail to me.

Alanco

 

Check out the brake article at the URL in my supplement. I won't use a booster because:
1. When hauling heavy, and even with a vacuum reservoir, there will be no brakes if the reservoir bled down during a long climb and you need immediate braking. Also if engine quits, no brakes. (Unless you install a hydrovac motor)

2. Won't work with a diesel engine. (No vacuum with diesels)

3. Factory boosters and M/C made for boosters have short stroke for low pedals. This is useless with no vacuum. Short stroke also has less brake feel and modulation.

I also will not use an OEM dual master on one of my old trucks because:

1. A lot of OEM M/C and other parts are not available after 10 years.

2. It is virtually impossible to match a disk caliper and master piston, and a drum wheel cylinder and master dual piston. One that worked well for manual disk brakes on a Ford Mustang and Falcon of 63-65 vintage is no longer available.

3. Since Stock Car Racing uses automobile derived brake parts, and nothing changes, parts are easy to get. The resizeable masters are made for use in a dual setup, and with residual valves or not, and with remote reservoirs or not and with a balance bar, and then you add an adjustable proportioning valve and there you are.

Alanco

My considerations are due to my uses of trucks. They have to be 4WD, they have to be drivers, haulers, and towers of fairly heavy trailers. Pretty little trucks are useless out here.

 

I was asked a couple more questions about my setup in another E-mail. Since I cannot reply that way.......

1. I had no clearance issues with the booster and dual resivour master cylinder under the cab. I did have to purchase a "kit" (from mid-fifty) to move the stock shifter linkage out of the way. I am running the factory drivetrain. 272 Y-block V8 and a light duty 3 speed manual (column shift).

2. My booster, master cylinder, and bracket originally came from CPP out in CA. I actually bought it from a friend of mine out there who decided not to use it on one of his trucks. It was new (as in never been used), but not directly from CPP.

3. I have the vacuum wipers still as well as the booster. I have a vacuum resivour mounted behind the drivers side running board. I have not had any issues since I installed that. Without it, I didn't have enough vacuum in certain cases to run both the wipers and the brake booster.

4. I have had the engine die (therefore no power brakes). They revert back to standing on the pedal as they were before the booster went on. Better to have them that way on a rare occasion, than to have them that way ever day.

I am not stating an argument with alanco, but I could have walked into NAPA and get the stock master cylinder for my 50+ year old truck should I have chosen too. I can get the original power steering pump from the same. Brake parts are all availble there (wheel cylinders, brake shoes). The distributors are available, distributor caps, distributor rotors, radiator caps, thermostats, plug wires, points and condensors, and just about every other tune up part.

Most parts are not as hard to get as people make them out to be.

Mine is a daily driver. I use it as a truck (just like the last 2 modern trucks I have owned), but it does no see the heavy duty work that bigger trucks get. I do not do that sort of work anymore.

 

"4. I have had the engine die (therefore no power brakes). They revert back to standing on the pedal as they were before the booster went on. Better to have them that way on a rare occasion, than to have them that way ever day."

You should be able to put a check valve in the vac line to the resivoir and prevent loss of vac in the resivoir when the engine dies. Depending on the size of the resivoir you should get one or more brake applications before you deplete the resivoir.

 

I do have one. Yes...the power brakes work for one application after it dies under normal circumstances.

It just did not have enough vacuum to come to a full stop at highway speeds in an emergency (I was running between 65-70 at the time ) Some dummy pulled right out in front of me last Saturday up in MO. That is the only time it has done it (so far).

 

Pappy and others, including Brian,

My intent here is to make it known to others that it is not hard to set up a boosterless disk brake system, with either firewall or underfloor mounting.

There is no intent to criticize someone's installation that improved his braking situation.

There is more than one way to do something, and my intent is to make it known how I now do it from knowledge gained in racing including engineering of brake systems which many in the forum do not understand as well as they should in my opinion.

I have predjudices up front: I do not like firewall mounting, and I do not like boosters and I and others have proved that easy braking without boosters is rather easy to do. I have provided a URL that gives this information.

I see no reason for anyone to get defensive.

 

I am in the same situation, trying to decide which way to go on my 56. I dont really have a problem with the residual valves, but will be using disc brakes front and rear. My only concern with the frame mount is room and heat from the exhaust. But I also really dont care for the look of the firewall mount on old trucks.

BTW, Brian. Be careful with the brake fluid in an oil squirt can. If you are using standard brake fluid, that oil can is not air tight and the brake fluid is absorbing moisture all the time. Even though you are only adding a little bit once or twice a year, you are putting moisture into your brake system. Not a good thing for stopping or brake repairs to come.

Bill

 

Quick advice: Don't use anything but silicone based brake fluid any more. The old type as you are cautioning Brian about is hydroscopic (absorbs moisture) and will ruin wheel cylinders and disc brake calipers. If you have an old truck with old fluid, you have to flush it with new fluid, but the new silicon based fluid does not attract moisture, and you could leave it in an open container like an oil can.

 

I'd like to echo Alanco's comments about silicone brake fluid. I used it in my stock 65 Mustang and in my modified 48 F-3 and have been very satisfied with the results. Living in a part of the country where the truck sits from November through April due to extreme winter weather conditions, the rebuilding of wheel cylinders every two years due to rust and corrosion is a PITA. I will use silicone in my next project too. It's a little more expensive than Dot 3 or 4 but worth it.

 

My head is swimming with all the information. Right now I am just going to put on a dual master for safety and stay with drum/drum and use a remote fill. Can someone tell me best place to get what I need? Will I need to put in residual valves/ proportioning valve? Is it 2lb for front and 10lb for rear on the residual valves? I know I will need to change the brake lines where they connect to the master. Do you need to run all new lines or can you cut the lines and attach new from there to the master? Not sure if I want to go to the silicone fluid. Seems like a lot of trouble trying to clean out the old fluid. Read a tech article that said it has its own issues and just should use a good DOT 3 fluid.

 

A drum/drum dual master cylinder will already have residual valves in it. It will already be sized for basic 1 1/8 wheel cylinders which is what the F-250 uses. If you have a F-100, the wheel cylinders are 1 1/16. Any Master Cylinder for drum/drum should have about a 1 3/8 to 1 1/2 inch pistons.

As far as the brake lines, all you have to do is plumb from the tee which connected the front lines to the back llines. Just use brass fittings to connect the lines individually to each connection on the dual master. There is no need for a proportioning valve on a drum/drum setup unless it would be an aftermarket adjustable one which would allow you to adjust the rear brakes to eliminate lockup if the truck were driven empty all the time. If you want a warning light, you would use a switch from a drum/drum setup which would require a connection from both the front and rear brake lines, and would be wired to a warning light.

Since the brakes are Bendix self energized brakes, they will stop very well with light pedal pressure, no need for power brakes.

It is well worth the trouble to use silicon brake fluid. By being non hydroscopic, it will not attract water and this will save all your wheel cylinders as well as the master cylinder from water damage. It is your choice, but in my opinion, as a brake servicer, I would never use alcohol based brake fluids, there is always rust damage in these old trucks when you service them. I have a pressure brake bleeder unit which couples on to a master cylinder and makes it easy to change fluid, but it is not all that much trouble to bleed brakes with a floor mounted reservoir on a dual master cylinder, since the reservoir holds so much fluid.

You may not know this, but DOT3 fluids require replacement every 2 years. COMPLETE REPLACEMENT! Who wants to do that, and how many people have ever done that? This is why all newer autos and trucks use silicon based brake fluid.

The only problem you may have is finding dual master cylinder that is made for floor mounting, as the advent of dual cylinders was about 1968 or so and all cars had suspended pedals by then. You will likely have to fabricate a bracket to mount the dual master cylinder.

Again, if it were me, I would keep the brake system stock, with a single master cylinder, and if I were after a dual system underfloor, I would use two individual master cylinders properly sized to accomplish the task. Then, if I went to front disks, I would only have to resize the piston in one cylinder, and add a proportioning valve, and remove the residual valve in the cylinder.

Alanco