What would happen if I used a 1" dual circuit M/C with my 1 1/8" wheel cylinders(in my '55 Ply)? If I'm thinking right, I'd get more mechanical advantage, but would require more brake pedal travel. right?
Hey: Remember when we were all younger and all we thought about was going faster? Now we're trying to figure out how to stop quicker. Just seemed funny.
Funny how we look at things differently when we get older. I didn't think twice about the brakes when I got the car. Now that I've had it awhile, a single M/C in a 4400LB car with no parking brake is making me nervous....
Yes. Less pedal effort needed. More foot travel needed. More braking force -- if you don't wind up banging the pedal on the floor. Hopefully you have enough travel to stop the car before your foot taps the floorboards. Just a thought. .
[QUOTE='29MurrayTub] Hopefully you have enough travel to stop the car before your foot taps the floorboards. Just a thought. .[/QUOTE] I'm marginally concerned about that. I think if I keep the brakes adjusted really well, I should be ok.
Here is a link and part of the brake article that might help you. http://www.hotrodheaven.com/tech/brakes/brakes4.htm#formula for master cylinder Formula for Master Cylinder Pressure I have been asked hundreds of times how do you determine the pressures output of the master cylinder. The following information will help you determine the proper size master cylinder: To figure how much pressure your master cylinder is putting out: C = pedal ratio D = pounds of pressure apply by your foot E = area of you master cylinder F = pounds of pressure out of the master cylinder C X D /(divided by) E = F Example: If you have a 1" master cylinder the area equals 1/2" x 1/2" x 3.14 = 0.785 Square Inches. So, 100 pounds (of applied foot pressure) X 6 (pedal ratio) divided by 0.785 = 764 pounds of pressure. If you have a 1-1/8" master cylinder, 100 psi X 6 (pedal ratio) divided by 0.9935 = 604 pounds of pressure. Here is some info on master cylinder with "constant" of 6 to 1 pedal ratio and 100 psi being applied. 3/4" master cylinder = 1359 psi 13/16" master cylinder = 1158 psi 7/8" master cylinder = 998 psi 15/16" master cylinder = 870 psi 1" master cylinder = 764 psi 1-1/8" master cylinder = 603 psi DO NOT Try to use a OEM master cylinder smaller than 1" without figuring out the volume requirement. It is like choosing between jump off a cliff or a plane, how do you want to die? Remember you can not do anything after you run out of brake fluid, but you can still press on the brake pedal harder. dso
Hang on a minute. The only relevant point is the size of the old master cylinder. The wheel cylinder size is irrelevant, or at least not enough info to go on. If the old master cylinder is also 1" the brakes will be the same. Mart.
THanks for the input all. The original single M/C is also 1 1/8" I guess I'll give it a try, if it doesn't work, I'll go shopping for a different cylinder.
I've been using a 7/8ths bore m/c from a '81 Granada with Manual disc/drum combo. I have used it with the Gm midsize front disc and a 8 or 9" rear and have great brakes without needing both feet to stop the car wich is usaually the case when the 1 1/8 m/c was used. Anything over 1" without a power ***ist will need too much pedal effort in my opinion.
I'll go along with Roadstar here. On my 32, 7/8" Torino M/C - which is probably the same as he's using, just has a different arrangement on the outlets - with 68-70 Mustang front discs and 68 Merc wagon rear drums. Easy pedal, power ***ist not needed - or wanted. Same setup on my 31 on 32 rails project except for Camaro front discs. (Mustang rotor is 11" and Camaro is 10 1/2".) The Mustang M/C in this case is identical with the Torino - 7/8". The Mustang M/C has the outlets pointed at the driveshaft and the Torino M/C has the outlets pointed at the left frame rail. I know you said 55 Plymouth, but a little extra info doesn't hurt. Depending on model the Plymouth probably weighs 3200# - 3800#. You gotta get into the Porky-Weight Challengers etc. to hit the 4400# mark.
http://www.jalopyjournal.com/forum/showthread.php?t=117976 You can go to napaonline and look up any car, for example 1966 Ford pickup and see what size the front and rear wheel cylinders are, then see what size bore the master has. 1" front, 7/8" rear, 1" master(not a dual reservoir) You now know what the factory did, you can look up the desired dual reservoir master, my case, the 80 Pinto is .93". For better brakes, you can increase the front cylinder slightly or decrease master size slightly. This gives you hydraulic advantage (leverage) and a 'power brake' feel and works well. Dont go so small on the master that it cant move enough fluid to fill the wheel cylinders. I got this idea from one of the brake websites, like Master Power Brakes, dont remember which one
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