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Brake System Question
Posted: May 27, 2007, 10:54 am
by tanman722001
Hi Guys,I was wondering if anyone has tried this.On my 66 F350 it has a booster type brakes (booster under driver floor).Was wonder if it would work I have a booster and master cly off a 78 Ford.Will it work if I put this on my 66 and redo the lines.So I could have newer power brakes on it?Yes the 66 has drums all the way around?What you think?Tony
Posted: May 27, 2007, 10:06 pm
by tanman722001
Anyone?
Posted: May 27, 2007, 11:51 pm
by Greg D
Tony, I don't know that much about your "big Slick" as we tend to call them. The last time I used a later model MC on a conversion I used one from a 1970 F100. I would tend to think you would want to make sure it is adequete for a bigger truck like yours though. I would check into one from a newer 350. Sounds like you have the right plan for the rest of it though, new lines etc.
Posted: May 28, 2007, 7:01 am
by DV65CustomCab
Tony, the booster wouldn't be a big deal but the master cylinder will require some research. You'll need it to be for drum brakes, first of all. Then it needs to have the same internal bore as the old one. When you start changing piston bore diameters you wind up in a very bad place trying to get things to work, as different bores move different amounts of fluid and affect how the brakes work. Very easy to wind up with much worse pedal effort or brakes that lock up on application. Old parts books usually had a section on the back that provided the bore information for cross referencing.
Posted: May 29, 2007, 7:57 am
by douglloyd
Tony,
My '66 1 ton has the booster mounted on the firewall. The shop manual shows details of the frame mounted booster if you want copies. Email me offline and I can send you pictures of my setup as well as the shop specs.
thanks,
Doug
Posted: May 29, 2007, 9:24 am
by FORDBOYpete
Tony,
Didn't I just respond to this same querey over at another Truck Site".
Essentially what I said: As long as you stay with a master Cyl made for Drum Brake Systems it should be a "walk in the park" for you. 
If you use Disc Brake M-Cyl you'll get application volume differential & probably run into residual PSI Valve issues also. A residual valve prevents "Drum Brake Slam" on application by holding residual PSI in the system to keep the return springs from fully collapsing wheel cyls. in a Drum Brake System.
Disc Brakes have no return springs in calipers. They rely on inherent system design, to provide adequate positioning & drag within the calipers.
Ever step on your pedal after R&Ring the pads on your Disc Brakes only to have it go to the boards? Then the next application they are fine from then on? Well that's what I'm rambling on about here.
A disc brake M-Cyl allows the return springs to collapse drum brake wheel cylinders too far & can cause "Slam On" during fast/sudden applications. It can be tough on Wet & Icy roads for sure.
FBp 