OK, it's time for me to ask my first dumb question. ( There will be more. ) What is wrong with the original power brake system that would justify all these efforts to replace it?
Well, to put it plainly, the factory setup is butt-UGLY. It looks like a cobbled together after thought, which basically, it was... The shock tower brace is especially hideous. It's a Master Cylinder? To my knowledge, they all work pretty much the same. Who cares what it came off of if it fits better then the factory one and works well? Hell, my Fiat has a Ford engine, Chevy ignition and a Dodge master cylinder.
The biggest problem with the factory set up is it cannot be used with the manual transmission. I prefer to to bang gears. All my Mavericks and Comet are manuals. I have the GEO article but it is a pretty small and light car. I don't know if that makes a difference on how brake systems are designed, but the Escort is much closer in weight than the GEO.
The main purpose of finding an alternative is for people that are adding power brakes to a manual brake car. You are right, the factory setup works great, and most people are not going to replace it just to get rid of the ugly tower brace -- it's too much work for not enough result, unless your goal IS to get rid of the tower brace. I am keeping an eye on it, because I want to put power brakes on the Grabber, but I don't really want to use the power setup from my 77 if there is a better looking alternative that works just as well. (And I don't particularly like the way the Geo master cylinder looks ) Given that there is a fair amount of work involved in just swapping in a factory setup, an alternative is attractive.
Ugly I can understand. Does anyone have a picture of a stock power brake setup? The car I'm working on has manual brakes and I plan on adding power. Even though this car will remain automatic, I would like to know (or see, as in picture) why a stick shift would interfere with power brakes. Guess I better go junk-yarding today. We have a local yard full of stuff from the 60s and 70s. Yes, while I'm there, I will make note of all the Comets and Mavericks that are there. Might even take a camera along.
The factory power booster / master cylinder is too big to fit behind the shock tower. Therefore, it is angled out into the center of the engine compartment. In order to give the brake pedal rod a straight shot into the back of the booster, the brake pedal comes down the left side of the column. where the clutch pedal should be, and the top is angled toward the center of the car.
For reasons I cant fathom, I guess it was easier to redesign the brake pedal assembly than design a smaller booster/mastercylinder set up.
Between Mavaholic's discription and Thack's picture I now understand why this reworking is needed. That is one butt ugly tower brace. In Thack's reply he mentioned "Mustang II front end". I have been thinking about putting one in the Comet since the first time I looked under the hood. I've put lots of them in street rods, but never thought about doing it to a "modern" vehicle. 11" disc brakes, rack and pinion steering, more spring and shock options, more room for bigger motors, more room for bigger and better headers, no shock tower braces at all, no shock towers at all, and gee wiz, more power brake options. I guess all I'm looking for is good excuse.
Hey Thack, I tried searching the site for pictures of the Mustang II conversion with no luck. Could you point me in the right dirrection or post some pics here? The more I think about doing this, the more I like it. Now I just have to sell this idea to my Grandson, since it is his car. Thanks a bunch
Resist what? I'm pretty sure all newer Ford and Chevy (and probably alot of other brand's) master cylinders are manufactured by the same company, Bendix. It's not like you're putting a 350 in your Maverick.
You are wrong. I know because I have extension training in Brakes and advanced suspension. A master cylinder size,bore size,stroke determines how it works and to what degree. Contrary to some people's beliefs that bigger is better is not always the case(there are some advantages but must be looked at from a systems approach) If you have four wheel disc brakes and want to stop in a hurry and split the system Meaning dual master cylinders(best way to go BTW) you want 3/4 bores for high pressure(manual use) if You are using a power setup a larger bore such as 1 inch to 1 and an 1/4 depending on if it is dual or single diaphram power power booster. You also need to know if the Master cylinder is internally proportion or not. I could go on but reality is most people will pat themselves on the back because they swapped in a part that fits. In Mavaholics case I believe the diameter he used is 7/8 and a dual diaphram power booster. That will work in his case. That is why the Geo metro swap works so well.
Dennis those restrictor valves ford used in that application tend to leak. I would buy new ones just to be safe. You can axe your prop valve as those restictors that screw in to the cylinder are the prop valves(in most cases)
